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Fawu Dong - One of the best experts on this subject based on the ideXlab platform.
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valepotriates from the roots and rhizomes of valeriana jatamansi jones as novel n type calcium channel antagonists
Frontiers in Pharmacology, 2018Co-Authors: Fawu Dong, Hehai Jiang, Liu Yang, Ye Gong, Dan Yang, Jian Yang, Yin NianAbstract:The roots and rhizomes of V. jatamansi have long been used as folk medicine in Asia and usually named as ″Zhizhuxiang″ in Chinese for the treatment of abdominal distention and pain. However, its active ingredients and molecular targets for treatment of abdominal pain remain unrevealed. Inhibitors of Cav2.2 N-type voltage-gated calcium channels (VGCCs) are actively sought after for their potential in treating pain, especially chronic pain. As far as we know, the method used for seeking analgesic active ingredient from plant material has rarely been reported. The analgesic potentials of the EtOH extract (0.01 mg/ml) of the roots and rhizomes of V. jatamansi and its EtOAc, n-BuOH and H2O soluble parts (0.01 mg/ml, respectively) were tested herein on Cav2.2, using whole-oocyte recordings in vitro by tow-electrode voltage clamp. The results indicated that the EtOAc-soluble part exhibiting the most potent inhibition of Cav2.2 peak current (20 mv). The EtOAc-soluble part was then subjected to silica gel column chromatography (CC) and giving 9 fractions. Phytochemical studies were carried out by repeated CC and extensive spectroscopic analysis after the fraction was identified active and got seventeen compounds (1-17). All isolates were then sent further for bioactive verification (1 and 3 at concentration of 10 μM, others at 30 μM). In addition, the selectivity of compounds 1 and 3 were tested on various ion channels including Cav1.2, Cav2.1 and Cav3.1 VGCCs and Kv1.2, Kv2.1, Kv3.1 and BK potassium channels. The results indicated that compounds 1 and 3 (an abundant compound) inhibited Cav2.2 with an EC50 of 3.3 μM and 4.8 μM respectively and had weaker or no effect on Cav1.2, Cav2.1 and Cav3.1 VGCCs and Kv1.2, Kv2.1, Kv3.1 and BK potassium channels. Compounds 1 and 3 appear to act as allosteric modulators rather than pore blockers of Cav2.2, which may play crucial role in attenuating nociception. The results of present research indicated that the ethnopharmacological utilization of V. jatamansi for relieving the abdominal distention and pain may mediate through Cav2.2 channel. Our work is the first demonstration of inhibition of Cav2.2 by iridoids, which may provide a fresh source for finding new analgesics.
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Valepotriates From the Roots and Rhizomes of Valeriana jatamansi Jones as Novel N-Type Calcium Channel Antagonists
Frontiers Media S.A., 2018Co-Authors: Fawu Dong, Hehai Jiang, Liu Yang, Ye Gong, Dan YangAbstract:The roots and rhizomes of Valeriana jatamansi have long been used as folk medicine in Asia and usually named as “Zhizhuxiang” in Chinese for the treatment of abdominal distention and pain. However, its active ingredients and molecular targets for treatment of abdominal pain remain unrevealed. Inhibitors of Cav2.2 N-type voltage-gated calcium channels (VGCCs) are actively sought after for their potential in treating pain, especially chronic pain. As far as we know, the method used for seeking analgesic active ingredient from plant material has rarely been reported. The analgesic potentials of the EtOH extract (0.01 mg/ml) of the roots and rhizomes of V. jatamansi and its EtOAc, n-BuOH and H2O soluble parts (0.01 mg/ml, respectively) were tested herein on Cav2.2, using whole-oocyte recordings in vitro by tow-electrode voltage clamp. The results indicated that the EtOAc-soluble part exhibited the most potent inhibition of Cav2.2 peak current (20 mv). The EtOAc-soluble part was then subjected to silica gel column chromatography (CC) and giving 9 fractions. Phytochemical studies were carried out by repeated CC and extensive spectroscopic analyses after the fraction (0.01 mg/ml) was identified to be active and got seventeen compounds (1–17). All isolates were then sent for further bioactive verification (1 and 3 at concentration of 10 μM, others at 30 μM). In addition, the selectivity of the active compounds 1 and 3 were tested on various ion channels including Cav1.2, Cav2.1 and Cav3.1 VGCCs and Kv1.2, Kv2.1, Kv3.1 and BK potassium channels. The results indicated that compound 1 and 3 (an abundant compound) inhibited Cav2.2 with an EC50 of 3.3 and 4.8 μM, respectively, and had weaker or no effect on Cav1.2, Cav2.1 and Cav3.1 VGCCs and Kv1.2, Kv2.1, Kv3.1 and BK potassium channels. Compounds 1 and 3 appear to act as allosteric modulators rather than pore blockers of Cav2.2, which may play crucial role in attenuating nociception. The results of present research indicated that the ethnopharmacological utilization of V. jatamansi for relieving the abdominal distention and pain may mediate through Cav2.2 channel. Our work is the first demonstration of inhibition of Cav2.2 by iridoids, which may provide a fresh source for finding new analgesics
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Data_Sheet_1_Valepotriates From the Roots and Rhizomes of Valeriana jatamansi Jones as Novel N-Type Calcium Channel Antagonists.pdf
2018Co-Authors: Fawu Dong, Hehai Jiang, Liu Yang, Ye Gong, Dan Yang, Jian Yang, Yin NianAbstract:The roots and rhizomes of Valeriana jatamansi have long been used as folk medicine in Asia and usually named as “Zhizhuxiang” in Chinese for the treatment of abdominal distention and pain. However, its active ingredients and molecular targets for treatment of abdominal pain remain unrevealed. Inhibitors of Cav2.2 N-type voltage-gated calcium channels (VGCCs) are actively sought after for their potential in treating pain, especially chronic pain. As far as we know, the method used for seeking analgesic active ingredient from plant material has rarely been reported. The analgesic potentials of the EtOH extract (0.01 mg/ml) of the roots and rhizomes of V. jatamansi and its EtOAc, n-BuOH and H2O soluble parts (0.01 mg/ml, respectively) were tested herein on Cav2.2, using whole-oocyte recordings in vitro by tow-electrode voltage clamp. The results indicated that the EtOAc-soluble part exhibited the most potent inhibition of Cav2.2 peak current (20 mv). The EtOAc-soluble part was then subjected to silica gel column chromatography (CC) and giving 9 fractions. Phytochemical studies were carried out by repeated CC and extensive spectroscopic analyses after the fraction (0.01 mg/ml) was identified to be active and got seventeen compounds (1–17). All isolates were then sent for further bioactive verification (1 and 3 at concentration of 10 μM, others at 30 μM). In addition, the selectivity of the active compounds 1 and 3 were tested on various ion channels including Cav1.2, Cav2.1 and Cav3.1 VGCCs and Kv1.2, Kv2.1, Kv3.1 and BK potassium channels. The results indicated that compound 1 and 3 (an abundant compound) inhibited Cav2.2 with an EC50 of 3.3 and 4.8 μM, respectively, and had weaker or no effect on Cav1.2, Cav2.1 and Cav3.1 VGCCs and Kv1.2, Kv2.1, Kv3.1 and BK potassium channels. Compounds 1 and 3 appear to act as allosteric modulators rather than pore blockers of Cav2.2, which may play crucial role in attenuating nociception. The results of present research indicated that the ethnopharmacological utilization of V. jatamansi for relieving the abdominal distention and pain may mediate through Cav2.2 channel. Our work is the first demonstration of inhibition of Cav2.2 by iridoids, which may provide a fresh source for finding new analgesics.
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cav2 2 and cav3 1 calcium channel inhibitors from valeriana jatamansi jones
RSC Advances, 2017Co-Authors: Fawu Dong, Hehai Jiang, Jian Yang, Jun Zhou, Yin NianAbstract:In China, the roots and rhizomes of Valeriana jatamansi Jones are traditionally used to treat gastrointestinal and rheumatic pain. Small molecule inhibitors of N-type (Cav2.2) and T-type (Cav3.1–3.3) calcium channels have become attractive resources in analgesic drug development. Therefore, in the present study, the isolated compounds (1–13) from V. jatamansi, including three new valepotriates (1–3), were initially evaluated on Cav2.2 and Cav3.1. As a result, compounds 1–12 showed weak to potent inhibition on Cav2.2 peak currents at 30 μM. Among them, compounds 1, 6, 7, 11 and 12 exhibited significant antagonistic effects, with EC50 values of 4.33, 2.18, 1.13, 2.70 and 7.8 μM, respectively. Meanwhile, the aforementioned compounds exhibited 18.2 ± 2.5% to 49.2 ± 7.1% peak current inhibition on Cav3.1 at 30 μM. In addition, they also exhibited noticeable specificity against Cav1.2, Cav2.1, and KCNH2 (hERG) channels.
Hehai Jiang - One of the best experts on this subject based on the ideXlab platform.
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valepotriates from the roots and rhizomes of valeriana jatamansi jones as novel n type calcium channel antagonists
Frontiers in Pharmacology, 2018Co-Authors: Fawu Dong, Hehai Jiang, Liu Yang, Ye Gong, Dan Yang, Jian Yang, Yin NianAbstract:The roots and rhizomes of V. jatamansi have long been used as folk medicine in Asia and usually named as ″Zhizhuxiang″ in Chinese for the treatment of abdominal distention and pain. However, its active ingredients and molecular targets for treatment of abdominal pain remain unrevealed. Inhibitors of Cav2.2 N-type voltage-gated calcium channels (VGCCs) are actively sought after for their potential in treating pain, especially chronic pain. As far as we know, the method used for seeking analgesic active ingredient from plant material has rarely been reported. The analgesic potentials of the EtOH extract (0.01 mg/ml) of the roots and rhizomes of V. jatamansi and its EtOAc, n-BuOH and H2O soluble parts (0.01 mg/ml, respectively) were tested herein on Cav2.2, using whole-oocyte recordings in vitro by tow-electrode voltage clamp. The results indicated that the EtOAc-soluble part exhibiting the most potent inhibition of Cav2.2 peak current (20 mv). The EtOAc-soluble part was then subjected to silica gel column chromatography (CC) and giving 9 fractions. Phytochemical studies were carried out by repeated CC and extensive spectroscopic analysis after the fraction was identified active and got seventeen compounds (1-17). All isolates were then sent further for bioactive verification (1 and 3 at concentration of 10 μM, others at 30 μM). In addition, the selectivity of compounds 1 and 3 were tested on various ion channels including Cav1.2, Cav2.1 and Cav3.1 VGCCs and Kv1.2, Kv2.1, Kv3.1 and BK potassium channels. The results indicated that compounds 1 and 3 (an abundant compound) inhibited Cav2.2 with an EC50 of 3.3 μM and 4.8 μM respectively and had weaker or no effect on Cav1.2, Cav2.1 and Cav3.1 VGCCs and Kv1.2, Kv2.1, Kv3.1 and BK potassium channels. Compounds 1 and 3 appear to act as allosteric modulators rather than pore blockers of Cav2.2, which may play crucial role in attenuating nociception. The results of present research indicated that the ethnopharmacological utilization of V. jatamansi for relieving the abdominal distention and pain may mediate through Cav2.2 channel. Our work is the first demonstration of inhibition of Cav2.2 by iridoids, which may provide a fresh source for finding new analgesics.
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Valepotriates From the Roots and Rhizomes of Valeriana jatamansi Jones as Novel N-Type Calcium Channel Antagonists
Frontiers Media S.A., 2018Co-Authors: Fawu Dong, Hehai Jiang, Liu Yang, Ye Gong, Dan YangAbstract:The roots and rhizomes of Valeriana jatamansi have long been used as folk medicine in Asia and usually named as “Zhizhuxiang” in Chinese for the treatment of abdominal distention and pain. However, its active ingredients and molecular targets for treatment of abdominal pain remain unrevealed. Inhibitors of Cav2.2 N-type voltage-gated calcium channels (VGCCs) are actively sought after for their potential in treating pain, especially chronic pain. As far as we know, the method used for seeking analgesic active ingredient from plant material has rarely been reported. The analgesic potentials of the EtOH extract (0.01 mg/ml) of the roots and rhizomes of V. jatamansi and its EtOAc, n-BuOH and H2O soluble parts (0.01 mg/ml, respectively) were tested herein on Cav2.2, using whole-oocyte recordings in vitro by tow-electrode voltage clamp. The results indicated that the EtOAc-soluble part exhibited the most potent inhibition of Cav2.2 peak current (20 mv). The EtOAc-soluble part was then subjected to silica gel column chromatography (CC) and giving 9 fractions. Phytochemical studies were carried out by repeated CC and extensive spectroscopic analyses after the fraction (0.01 mg/ml) was identified to be active and got seventeen compounds (1–17). All isolates were then sent for further bioactive verification (1 and 3 at concentration of 10 μM, others at 30 μM). In addition, the selectivity of the active compounds 1 and 3 were tested on various ion channels including Cav1.2, Cav2.1 and Cav3.1 VGCCs and Kv1.2, Kv2.1, Kv3.1 and BK potassium channels. The results indicated that compound 1 and 3 (an abundant compound) inhibited Cav2.2 with an EC50 of 3.3 and 4.8 μM, respectively, and had weaker or no effect on Cav1.2, Cav2.1 and Cav3.1 VGCCs and Kv1.2, Kv2.1, Kv3.1 and BK potassium channels. Compounds 1 and 3 appear to act as allosteric modulators rather than pore blockers of Cav2.2, which may play crucial role in attenuating nociception. The results of present research indicated that the ethnopharmacological utilization of V. jatamansi for relieving the abdominal distention and pain may mediate through Cav2.2 channel. Our work is the first demonstration of inhibition of Cav2.2 by iridoids, which may provide a fresh source for finding new analgesics
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Data_Sheet_1_Valepotriates From the Roots and Rhizomes of Valeriana jatamansi Jones as Novel N-Type Calcium Channel Antagonists.pdf
2018Co-Authors: Fawu Dong, Hehai Jiang, Liu Yang, Ye Gong, Dan Yang, Jian Yang, Yin NianAbstract:The roots and rhizomes of Valeriana jatamansi have long been used as folk medicine in Asia and usually named as “Zhizhuxiang” in Chinese for the treatment of abdominal distention and pain. However, its active ingredients and molecular targets for treatment of abdominal pain remain unrevealed. Inhibitors of Cav2.2 N-type voltage-gated calcium channels (VGCCs) are actively sought after for their potential in treating pain, especially chronic pain. As far as we know, the method used for seeking analgesic active ingredient from plant material has rarely been reported. The analgesic potentials of the EtOH extract (0.01 mg/ml) of the roots and rhizomes of V. jatamansi and its EtOAc, n-BuOH and H2O soluble parts (0.01 mg/ml, respectively) were tested herein on Cav2.2, using whole-oocyte recordings in vitro by tow-electrode voltage clamp. The results indicated that the EtOAc-soluble part exhibited the most potent inhibition of Cav2.2 peak current (20 mv). The EtOAc-soluble part was then subjected to silica gel column chromatography (CC) and giving 9 fractions. Phytochemical studies were carried out by repeated CC and extensive spectroscopic analyses after the fraction (0.01 mg/ml) was identified to be active and got seventeen compounds (1–17). All isolates were then sent for further bioactive verification (1 and 3 at concentration of 10 μM, others at 30 μM). In addition, the selectivity of the active compounds 1 and 3 were tested on various ion channels including Cav1.2, Cav2.1 and Cav3.1 VGCCs and Kv1.2, Kv2.1, Kv3.1 and BK potassium channels. The results indicated that compound 1 and 3 (an abundant compound) inhibited Cav2.2 with an EC50 of 3.3 and 4.8 μM, respectively, and had weaker or no effect on Cav1.2, Cav2.1 and Cav3.1 VGCCs and Kv1.2, Kv2.1, Kv3.1 and BK potassium channels. Compounds 1 and 3 appear to act as allosteric modulators rather than pore blockers of Cav2.2, which may play crucial role in attenuating nociception. The results of present research indicated that the ethnopharmacological utilization of V. jatamansi for relieving the abdominal distention and pain may mediate through Cav2.2 channel. Our work is the first demonstration of inhibition of Cav2.2 by iridoids, which may provide a fresh source for finding new analgesics.
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cav2 2 and cav3 1 calcium channel inhibitors from valeriana jatamansi jones
RSC Advances, 2017Co-Authors: Fawu Dong, Hehai Jiang, Jian Yang, Jun Zhou, Yin NianAbstract:In China, the roots and rhizomes of Valeriana jatamansi Jones are traditionally used to treat gastrointestinal and rheumatic pain. Small molecule inhibitors of N-type (Cav2.2) and T-type (Cav3.1–3.3) calcium channels have become attractive resources in analgesic drug development. Therefore, in the present study, the isolated compounds (1–13) from V. jatamansi, including three new valepotriates (1–3), were initially evaluated on Cav2.2 and Cav3.1. As a result, compounds 1–12 showed weak to potent inhibition on Cav2.2 peak currents at 30 μM. Among them, compounds 1, 6, 7, 11 and 12 exhibited significant antagonistic effects, with EC50 values of 4.33, 2.18, 1.13, 2.70 and 7.8 μM, respectively. Meanwhile, the aforementioned compounds exhibited 18.2 ± 2.5% to 49.2 ± 7.1% peak current inhibition on Cav3.1 at 30 μM. In addition, they also exhibited noticeable specificity against Cav1.2, Cav2.1, and KCNH2 (hERG) channels.
Pietro Mesirca - One of the best experts on this subject based on the ideXlab platform.
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evidence for a selective blockade of Cav1.2 versus cav1 3 by the mamba toxin calciseptine in the mouse heart
Archives of Cardiovascular Diseases Supplements, 2020Co-Authors: Christian Barrere, Matteo E Mangoni, Pietro Mesirca, Stephanie Barrerelemaire, K Chinda, C Aurelie, S Diochot, Michel Lazdunski, Joel NargeotAbstract:Introduction Selective blockers are important tools for identifying the physiological role of ion channels isoforms. L-type calcium channels are high voltage activated channels sensitive to dihydropyridine (DHP). Two distinct isoforms (a1 C/Cav1.2 and a1D/Cav1.3) mediate calcium entry into cardiac cells to trigger contraction or contribute to heart rate generation. Many classes of drugs have been shown to target L-type calcium channels but poor selectivity has been reported between Cav1.2 and Cav1.3. Objective Our goal is to look for an animal toxin able to discriminate between these two L-type calcium channel isoforms. We focused on calciseptine, a snake toxin purified from mamba venom which decreases, via Cav1.2 inhibition, vascular and cardiac contraction without affecting heart rate (De Weille et al., 2001). Methods We compared the effect of calciseptine and of a classical DHP on the contraction amplitude and heart rate in Langendorf perfused hearts from wild-type mice and mice carrying Cav1.2 channels insensitive to DHP. Results Calciseptine 100 nM strongly decreased the amplitude of contractions by 82%. Increasing the concentration up to 1 μM further reduced the contraction while no modification of the heart rate was noticed. The frequency of spontaneous AP recorded from sinus node using the patch clamp technique was also unaffected by 100 nM calciseptine. (216 ± 20 bpm ctrl vs. 212 ± 22 bpm calciseptine). On the other hand, 3 μM nifedipine, which blocks both Cav1.2 and Cav1.3 channels decreased contraction and heart rate in isolated mouse heart, induced arrhythmias and strongly reduced AP frequency in isolated sinus node cells (193 ± 10 bpm ctrl vs. 48 ± 9 bpm nifedipine). Conclusions These preliminary data suggest that calciseptine may act as a specific blocker of Cav1.2 versus Cav1.3, a result to be confirmed by direct exploration of the effect of calciseptine on native ventricular and SAN cells calcium currents or on recombinant Cav1.2 and Cav1.3 currents.
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Concomitant genetic ablation of L-type Cav1.3 (α1D) and T-type Cav3.1 (α1G) Ca2+ channels disrupts heart automaticity
Scientific Reports, 2020Co-Authors: M Baudot, L Fossier, L Talssi, Isabelle Bidaud, Joel Nargeot, Eleonora Torre, Julien Louradour, Angelo Torrente, Stéphanie Barrère-lemaire, Pietro MesircaAbstract:Cardiac automaticity is set by pacemaker activity of the sinus node (SAN). In addition to the ubiquitously expressed cardiac voltage-gated L-type Cav1.2 Ca2+ channel isoform, pacemaker cells within the SAN and the atrioventricular node co-express voltage-gated L-type Cav1.3 and T-type Cav3.1 Ca2+ channels (SAN-VGCCs). The role of SAN-VGCCs in automaticity is incompletely understood. We used knockout mice carrying individual genetic ablation of Cav1.3 (Cav1.3-/-) or Cav3.1 (Cav3.1-/-) channels and double mutant Cav1.3-/-/Cav3.1-/- mice expressing only Cav1.2 channels. We show that concomitant loss of SAN-VGCCs prevents physiological SAN automaticity, blocks impulse conduction and compromises ventricular rhythmicity. Coexpression of SAN-VGCCs is necessary for impulse formation in the central SAN. In mice lacking SAN-VGCCs, residual pacemaker activity is predominantly generated in peripheral nodal and extranodal sites by f-channels and TTX-sensitive Na+ channels. In beating SAN cells, ablation of SAN-VGCCs disrupted late diastolic local intracellular Ca2+ release, which demonstrates an important role for these channels in supporting the sarcoplasmic reticulum based "Ca2+ clock" mechanism during normal pacemaking. These data implicate an underappreciated role for co-expression of SAN-VGCCs in heart automaticity and define an integral role for these channels in mechanisms that control the heartbeat.
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heart automaticity in mice lacking l type cav1 3 and t type cav3 1 ca2 channels insights into the cardiac pacemaker mechanism
Archives of Cardiovascular Diseases Supplements, 2018Co-Authors: M Baudot, L Fossier, L Talssi, Heesup Shin, Joerg Striessnig, Angelo G. Torrente, Isabelle Bidaud, Pietro Mesirca, Joel Nargeot, Stephanie BarrerelemaireAbstract:Introduction Sino-atrial node (SAN) pacemaker activity is generated by ion channels of the plasma membrane, such as hyperpolarization-activated “funny” f-(HCN), Ca2+ channels and ryanodine receptor (RyR) – dependent Ca2+ release from the sarcoplasmic reticulum (SR). It is currently disputed whether Ca2+ release from RyRs could sustain viable pacemaker activity provided preserved SR Ca2+ content. While working myocytes express L-type Cav1.2 channels to maintain SR Ca2+ content, SAN cells express also L-type Cav1.3 and T-type Cav3.1 channels to generate pacemaking. Objectives We used mutant mice carrying concomitant ablation of Cav1.3 and Cav3.1 (Cav1.3−/−/Cav3.1−/−) to study the importance of these channels in automaticity. We also investigated the role of f-HCN channels and RyR-dependent Ca2+ release in residual pacemaker activity of mutant mice. Methods We employed in vivo telemetric recordings of heart rate (HR) in Cav1.3−/−, Cav3.1−/− and Cav1.3−/−/Cav3.1−/− mice. We studied the consequences of pharmacologic inhibition of f-HCN and TTX-sensitive Na+ channels in mutant mice using Langendorff perfused hearts or optical mapping (OM) of the pacemaker impulse in intact SAN preparations (SANs). Results Cav ablation reduced HR in mice: Cav3.1−/− (−7.6%, n = 11), Cav1.3−/− (−24.4%, n = 8), Cav1.3−/−/Cav3.1−/− (−35%, n = 11). In OM experiments on SANs, concomitant inhibition of f-HCN and Nav1.1 channels slowed pacemaking in wild-type (−48%, n = 7) and Cav3.1−/− (−37%, n = 7), while arresting automaticity in 4/6 of Cav1.3−/−, 3/6 of Cav1.3−/−/Cav3.1−/−. When present, residual pacemaking was reduced by 82%. Similar results were obtained using isolated Cav1.3−/−/Cav3.1−/− pacemaker cells were automaticity arrested in 5/9 cells tested, or was reduced by 80% in 4/9 cells. Conclusion Heart automaticity is primarily generated by Cav1.3 and f-HCN channels. RyR-dependent Ca2+ release cannot sustain automaticity following concomitant targeting of Cav1.3 and f-HCN channels.
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cav1 3 l type ca2 channel contributes to the heartbeat by generating a dihydropyridine sensitive persistent na current
Scientific Reports, 2017Co-Authors: Futoshi Toyoda, Joerg Striessnig, Matteo E Mangoni, Pietro Mesirca, Stefan Dübel, Wei-guang Ding, Hiroshi MatsuuraAbstract:The spontaneous activity of sinoatrial node (SAN) pacemaker cells is generated by a functional interplay between the activity of ionic currents of the plasma membrane and intracellular Ca2+ dynamics. The molecular correlate of a dihydropyridine (DHP)-sensitive sustained inward Na+ current (I st), a key player in SAN automaticity, is still unknown. Here we show that I st and the L-type Ca2+ current (I Ca,L) share CaV1.3 as a common molecular determinant. Patch-clamp recordings of mouse SAN cells showed that I st is activated in the diastolic depolarization range, and displays Na+ permeability and minimal inactivation and sensitivity to I Ca,L activators and blockers. Both CaV1.3-mediated I Ca,L and I st were abolished in CaV1.3-deficient (CaV1.3-/-) SAN cells but the Cav1.2-mediated I Ca,L current component was preserved. In SAN cells isolated from mice expressing DHP-insensitive Cav1.2 channels (Cav1.2DHP-/-), I st and CaV1.3-mediated I Ca,L displayed overlapping sensitivity and concentration-response relationships to the DHP blocker nifedipine. Consistent with the hypothesis that CaV1.3 rather than Cav1.2 underlies I st, a considerable fraction of I Ca,L was resistant to nifedipine inhibition in Cav1.2DHP-/- SAN cells. These findings identify CaV1.3 channels as essential molecular components of the voltage-dependent, DHP-sensitive I st Na+ current in the SAN.
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role of l type cav1 3 ca2 channels in ca2 handling and san pacemaker activity altered by external conditions
Archives of Cardiovascular Diseases Supplements, 2017Co-Authors: Angelo G. Torrente, M Baudot, Pietro Mesirca, B Isabelle, B Christian, R Julien, S JoergAbstract:Introduction Membrane currents and Ca2+ handling generate Sinoatrial node (SAN) automaticity. Several studies showed the negative effect of membrane current impairment, while it is unknown how abnormal Ca2+ affect pacemaking. Purpose To investigate SAN automaticity when Ca2+ handling is altered by external conditions. Methods We video recorded contraction amplitude and spontaneous rate of SAN cells. Results In WT, 0.9 mM external Ca2+ ([Ca2+]0) reduces cell shortening, while 3 mM increased it, compared to control solution (1.8 mM [Ca2+]0). Lowering [Ca2+]0 to 0.9 mM did not affect WT automaticity, while high [Ca2+]0 dysregulate it without changing the average rate. L-type channels (LTCCs) are the main Ca2+ source in SAN cells, with Cav1.3 as the dominant isoform and Cav1.2 less expressed. To discern their role during abnormal [Ca2+]0, we used mice lacking Cav1.3 channels (Cav1.3−/−). As in WT, 0.9 mM [Ca2+]0 decreased cell shortening in Cav1.3−/−, while only a tendency to increase was determined by 3 mM [Ca2+]0. Also, high [Ca2+]0 significantly reduced spontaneous rate in Cav1.3−/− cells. Stimulation of WT cells with the LTCC dihydropyridine agonist BayK 8644 (BayK) increased cell shortening and spontaneous rate. Under BayK, Cav1.3−/− cells showed similar increase of contraction amplitude but reduced rate acceleration than WT. We repeated this protocol with a mouse where Cav1.2 is dihydropyridines insensitive (Cav1.2DHP−/−). Cav1.2DHP−/− SAN cells responded like WT to abnormal [Ca2+]0. Instead, BayK caused rate increase equivalent to WT but reduced contraction shortening in Cav1.2DHP−/−. Conclusion Abnormal increase of Ca2+ influx dysregulates automaticity in WT cells, likely through hyper-stimulation of Ca2+ activated currents. Moreover, selective stimulation of Cav1.2 and/or Cav1.3 with BayK suggests that Cav1.2 maintain the bulk of Ca2+ allowing proper contraction, while Cav1.3 mainly carry the influx of Ca2+ needed to trigger SAN automaticity.
Joerg Striessnig - One of the best experts on this subject based on the ideXlab platform.
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heart automaticity in mice lacking l type cav1 3 and t type cav3 1 ca2 channels insights into the cardiac pacemaker mechanism
Archives of Cardiovascular Diseases Supplements, 2018Co-Authors: M Baudot, L Fossier, L Talssi, Heesup Shin, Joerg Striessnig, Angelo G. Torrente, Isabelle Bidaud, Pietro Mesirca, Joel Nargeot, Stephanie BarrerelemaireAbstract:Introduction Sino-atrial node (SAN) pacemaker activity is generated by ion channels of the plasma membrane, such as hyperpolarization-activated “funny” f-(HCN), Ca2+ channels and ryanodine receptor (RyR) – dependent Ca2+ release from the sarcoplasmic reticulum (SR). It is currently disputed whether Ca2+ release from RyRs could sustain viable pacemaker activity provided preserved SR Ca2+ content. While working myocytes express L-type Cav1.2 channels to maintain SR Ca2+ content, SAN cells express also L-type Cav1.3 and T-type Cav3.1 channels to generate pacemaking. Objectives We used mutant mice carrying concomitant ablation of Cav1.3 and Cav3.1 (Cav1.3−/−/Cav3.1−/−) to study the importance of these channels in automaticity. We also investigated the role of f-HCN channels and RyR-dependent Ca2+ release in residual pacemaker activity of mutant mice. Methods We employed in vivo telemetric recordings of heart rate (HR) in Cav1.3−/−, Cav3.1−/− and Cav1.3−/−/Cav3.1−/− mice. We studied the consequences of pharmacologic inhibition of f-HCN and TTX-sensitive Na+ channels in mutant mice using Langendorff perfused hearts or optical mapping (OM) of the pacemaker impulse in intact SAN preparations (SANs). Results Cav ablation reduced HR in mice: Cav3.1−/− (−7.6%, n = 11), Cav1.3−/− (−24.4%, n = 8), Cav1.3−/−/Cav3.1−/− (−35%, n = 11). In OM experiments on SANs, concomitant inhibition of f-HCN and Nav1.1 channels slowed pacemaking in wild-type (−48%, n = 7) and Cav3.1−/− (−37%, n = 7), while arresting automaticity in 4/6 of Cav1.3−/−, 3/6 of Cav1.3−/−/Cav3.1−/−. When present, residual pacemaking was reduced by 82%. Similar results were obtained using isolated Cav1.3−/−/Cav3.1−/− pacemaker cells were automaticity arrested in 5/9 cells tested, or was reduced by 80% in 4/9 cells. Conclusion Heart automaticity is primarily generated by Cav1.3 and f-HCN channels. RyR-dependent Ca2+ release cannot sustain automaticity following concomitant targeting of Cav1.3 and f-HCN channels.
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cav1 3 l type ca2 channel contributes to the heartbeat by generating a dihydropyridine sensitive persistent na current
Scientific Reports, 2017Co-Authors: Futoshi Toyoda, Joerg Striessnig, Matteo E Mangoni, Pietro Mesirca, Stefan Dübel, Wei-guang Ding, Hiroshi MatsuuraAbstract:The spontaneous activity of sinoatrial node (SAN) pacemaker cells is generated by a functional interplay between the activity of ionic currents of the plasma membrane and intracellular Ca2+ dynamics. The molecular correlate of a dihydropyridine (DHP)-sensitive sustained inward Na+ current (I st), a key player in SAN automaticity, is still unknown. Here we show that I st and the L-type Ca2+ current (I Ca,L) share CaV1.3 as a common molecular determinant. Patch-clamp recordings of mouse SAN cells showed that I st is activated in the diastolic depolarization range, and displays Na+ permeability and minimal inactivation and sensitivity to I Ca,L activators and blockers. Both CaV1.3-mediated I Ca,L and I st were abolished in CaV1.3-deficient (CaV1.3-/-) SAN cells but the Cav1.2-mediated I Ca,L current component was preserved. In SAN cells isolated from mice expressing DHP-insensitive Cav1.2 channels (Cav1.2DHP-/-), I st and CaV1.3-mediated I Ca,L displayed overlapping sensitivity and concentration-response relationships to the DHP blocker nifedipine. Consistent with the hypothesis that CaV1.3 rather than Cav1.2 underlies I st, a considerable fraction of I Ca,L was resistant to nifedipine inhibition in Cav1.2DHP-/- SAN cells. These findings identify CaV1.3 channels as essential molecular components of the voltage-dependent, DHP-sensitive I st Na+ current in the SAN.
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the physiology pathology and pharmacology of voltage gated calcium channels and their future therapeutic potential
Pharmacological Reviews, 2015Co-Authors: Joerg Striessnig, Alexandra Koschak, Annette C DolphinAbstract:Voltage-gated calcium channels are required for many key functions in the body. In this review, the different subtypes of voltage-gated calcium channels are described and their physiologic roles and pharmacology are outlined. We describe the current uses of drugs interacting with the different calcium channel subtypes and subunits, as well as specific areas in which there is strong potential for future drug development. Current therapeutic agents include drugs targeting L-type Cav1.2 calcium channels, particularly 1,4-dihydropyridines, which are widely used in the treatment of hypertension. T-type (CaV3) channels are a target of ethosuximide, widely used in absence epilepsy. The auxiliary subunit α2δ-1 is the therapeutic target of the gabapentinoid drugs, which are of value in certain epilepsies and chronic neuropathic pain. The limited use of intrathecal ziconotide, a peptide blocker of N-type (CaV2.2) calcium channels, as a treatment of intractable pain, gives an indication that these channels represent excellent drug targets for various pain conditions. We describe how selectivity for different subtypes of calcium channels (e.g., Cav1.2 and CaV1.3 L-type channels) may be achieved in the future by exploiting differences between channel isoforms in terms of sequence and biophysical properties, variation in splicing in different target tissues, and differences in the properties of the target tissues themselves in terms of membrane potential or firing frequency. Thus, use-dependent blockers of the different isoforms could selectively block calcium channels in particular pathologies, such as nociceptive neurons in pain states or in epileptic brain circuits. Of important future potential are selective CaV1.3 blockers for neuropsychiatric diseases, neuroprotection in Parkinson’s disease, and resistant hypertension. In addition, selective or nonselective T-type channel blockers are considered potential therapeutic targets in epilepsy, pain, obesity, sleep, and anxiety. Use-dependent N-type calcium channel blockers are likely to be of therapeutic use in chronic pain conditions. Thus, more selective calcium channel blockers hold promise for therapeutic intervention.
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channelopathies in cav1 1 cav1 3 and cav1 4 voltage gated l type ca2 channels
Pflügers Archiv: European Journal of Physiology, 2010Co-Authors: Joerg Striessnig, Hanno J Bolz, Alexandra KoschakAbstract:Voltage-gated Ca2+ channels couple membrane depolarization to Ca2+-dependent intracellular signaling events. This is achieved by mediating Ca2+ ion influx or by direct conformational coupling to intracellular Ca2+ release channels. The family of Cav1 channels, also termed L-type Ca2+ channels (LTCCs), is uniquely sensitive to organic Ca2+ channel blockers and expressed in many electrically excitable tissues. In this review, we summarize the role of LTCCs for human diseases caused by genetic Ca2+ channel defects (channelopathies). LTCC dysfunction can result from structural aberrations within their pore-forming α1 subunits causing hypokalemic periodic paralysis and malignant hyperthermia sensitivity (Cav1.1 α1), incomplete congenital stationary night blindness (CSNB2; Cav1.4 α1), and Timothy syndrome (Cav1.2 α1; reviewed separately in this issue). Cav1.3 α1 mutations have not been reported yet in humans, but channel loss of function would likely affect sinoatrial node function and hearing. Studies in mice revealed that LTCCs indirectly also contribute to neurological symptoms in Ca2+ channelopathies affecting non-LTCCs, such as Cav2.1 α1 in tottering mice. Ca2+ channelopathies provide exciting disease-related molecular detail that led to important novel insight not only into disease pathophysiology but also to mechanisms of channel function.
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loss of cav1 3 channels reveals the critical role of l type and bk channel coupling in pacemaking mouse adrenal chromaffin cells
The Journal of Neuroscience, 2010Co-Authors: Andrea Marcantoni, Joerg Striessnig, Satyajit Mahapatra, David H F Vandael, Valentina Carabelli, Martina J Sinneggerbrauns, Emilio CarboneAbstract:We studied wild-type (WT) and Cav1.3−/− mouse chromaffin cells (MCCs) with the aim to determine the isoform of L-type Ca2+ channel (LTCC) and BK channels that underlie the pacemaker current controlling spontaneous firing. Most WT-MCCs (80%) were spontaneously active (1.5 Hz) and highly sensitive to nifedipine and BayK-8644 (1,4-dihydro-2,6-dimethyl-5-nitro-4-[2-(trifluoromethyl)phenyl]-3-pyridinecarboxylic acid, methyl ester). Nifedipine blocked the firing, whereas BayK-8644 increased threefold the firing rate. The two dihydropyridines and the BK channel blocker paxilline altered the shape of action potentials (APs), suggesting close coupling of LTCCs to BK channels. WT-MCCs expressed equal fractions of functionally active Cav1.2 and Cav1.3 channels. Cav1.3 channel deficiency decreased the number of normally firing MCCs (30%; 2.0 Hz), suggesting a critical role of these channels on firing, which derived from their slow inactivation rate, sizeable activation at subthreshold potentials, and close coupling to fast inactivating BK channels as determined by using EGTA and BAPTA Ca2+ buffering. By means of the action potential clamp, in TTX-treated WT-MCCs, we found that the interpulse pacemaker current was always net inward and dominated by LTCCs. Fast inactivating and non-inactivating BK currents sustained mainly the afterhyperpolarization of the short APs (2–3 ms) and only partially the pacemaker current during the long interspike (300–500 ms). Deletion of Cav1.3 channels reduced drastically the inward Ca2+ current and the corresponding Ca2+-activated BK current during spikes. Our data highlight the role of Cav1.3, and to a minor degree of Cav1.2, as subthreshold pacemaker channels in MCCs and open new interesting features about their role in the control of firing and catecholamine secretion at rest and during sustained stimulations matching acute stress.
Richard B. Silverman - One of the best experts on this subject based on the ideXlab platform.
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structure activity relationship of n n disubstituted pyrimidinetriones as cav1 3 calcium channel selective antagonists for parkinson s disease
Journal of Medicinal Chemistry, 2013Co-Authors: Soosung Kang, Garry Cooper, Sara Fernandez Dunne, Chi Hao Luan, James D Surmeier, Richard B. SilvermanAbstract:CaV1.3 L-type calcium channels (LTCCs) have been a potential target for Parkinson’s disease since calcium ion influx through the channel was implicated in the generation of mitochondrial oxidative stress, causing cell death in the dopaminergic neurons. Selective inhibition of CaV1.3 over other LTCC isoforms, especially Cav1.2, is critical to minimize potential side effects. We recently identified pyrimidinetriones (PYTs) as a CaV1.3-selective scaffold; here we report the structure–activity relationship of PYTs with both CaV1.3 and Cav1.2 LTCCs. By variation of the substituents on the cyclopentyl and arylalkyl groups of PYT, SAR studies allowed characterization of the CaV1.3 and Cav1.2 LTCCs binding sites. The SAR also identified four important moieties that either retain selectivity or enhance binding affinity. Our study represents a significant enhancement of the SAR of PYTs at CaV1.3 and Cav1.2 LTCCs and highlights several advances in the lead optimization and diversification of this family of compounds...
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Antagonism of L-type Ca2+ channels CaV1.3 and Cav1.2 by 1,4-dihydropyrimidines and 4H-pyrans as dihydropyridine mimics
Bioorganic & medicinal chemistry, 2013Co-Authors: Soosung Kang, D. James Surmeier, Garry Cooper, Sara Fernandez Dunne, Chi Hao Luan, Richard B. SilvermanAbstract:The L-type calcium channel (LTCC) CaV1.3 is regarded as a new potential therapeutic target for Parkinson’s disease. Calcium influx through CaV1.3 LTCC during autonomous pacemaking in adult dopaminergic neurons of the substantia nigra pars compacta is related to the generation of mitochondrial oxidative stress in animal models. Development of a CaV1.3 antagonist selective over Cav1.2 is essential because Cav1.2 pore-forming subunits are the predominant form of LTCCs and are abundant in the central nervous and cardiovascular systems. We have explored 1,4-dihydropyrimidines and 4H-pyrans to identify potent and selective antagonists of CaV1.3 relative to Cav1.2 LTCCs. A library of 36 dihydropyridine (DHP)-mimic 1,4-dihydropyrimidines and 4H-pyrans was synthesized, and promising chiral compounds were resolved. The antagonism studies of CaV1.3 and Cav1.2 LTCCs using DHP mimic compounds showed that dihydropyrimidines and 4H-pyrans are effective antagonists of DHPs for CaV1.3 LTCCs. Some 1,4-dihydropyrimidines are more selective than isradipine for CaV1.3 over Cav1.2, shown here by both calcium flux and patch-clamp electrophysiology experiments, where the ratio of antagonism is around 2–3. These results support the hypothesis that the modified hydrogen bonding donor/acceptors in DHP-mimic dihydropyrimidines and 4H-pyrans can interact differently with DHP binding sites, but, in addition, the data suggest that the binding sites of DHP in CaV1.3 and Cav1.2 LTCCs are very similar.
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Antagonism of 4-substituted 1,4-dihydropyridine-3,5-dicarboxylates toward voltage-dependent L-type Ca2+ channels CaV1.3 and Cav1.2
Bioorganic & medicinal chemistry, 2010Co-Authors: Che Chien Chang, D. James Surmeier, Soosung Kang, Sara Fernandez Dunne, Chi Hao Luan, Song Cao, Li Kai, Xinyong Tian, Prativa Pandey, Richard B. SilvermanAbstract:Abstract L-type Ca2+ channels in mammalian brain neurons have either a Cav1.2 or CaV1.3 pore-forming subunit. Recently, it was shown that CaV1.3 Ca2+ channels underlie autonomous pacemaking in adult dopaminergic neurons in the substantia nigra pars compacta, and this reliance renders them sensitive to toxins used to create animal models of Parkinson’s disease. Antagonism of these channels with the dihydropyridine antihypertensive drug isradipine diminishes the reliance on Ca2+ and the sensitivity of these neurons to toxins, pointing to a potential neuroprotective strategy. However, for neuroprotection without an antihypertensive side effect, selective CaV1.3 channel antagonists are required. In an attempt to identify potent and selective antagonists of CaV1.3 channels, 124 dihydropyridines (4-substituted-1,4-dihydropyridine-3,5-dicarboxylic diesters) were synthesized. The antagonism of heterologously expressed Cav1.2 and CaV1.3 channels was then tested using electrophysiological approaches and the FLIPR Calcium 4 assay. Despite the large diversity in substitution on the dihydropyridine scaffold, the most CaV1.3 selectivity was only about twofold. These results support a highly similar dihydropyridine binding site at both Cav1.2 and CaV1.3 channels and suggests that other classes of compounds need to be identified for CaV1.3 selectivity.