The Experts below are selected from a list of 1917 Experts worldwide ranked by ideXlab platform
Laura Anselmi - One of the best experts on this subject based on the ideXlab platform.
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Galanin inhibition of voltage dependent ca2 influx in rat cultured myenteric neurons is mediated by Galanin Receptor 1
2009Co-Authors: Laura Anselmi, Catia Sternini, Salvatore L Stella, Nicholas C BrechaAbstract:Galanin activates three Receptors, the Galanin Receptor 1 (GalR1), GalR2, and GalR3. In the gastrointestinal tract, GalR1 mediates the Galanin inhibition of cholinergic transmission to the longitudinal muscle and reduction of peristalsis efficiency in the small intestine. Galanin has also been shown to inhibit depolarization-evoked Ca2+ increases in cultured myenteric neurons. Because GalR1 immunoreactivity is localized to cholinergic myenteric neurons, we hypothesized that this inhibitory action of Galanin on myenteric neurons is mediated by GalR1. We investigated the effect of Galanin 1-16, which has high affinity for GalR1 and GalR2, in the presence or absence of the selective GalR1 antagonist, RWJ-57408, and of Galanin 2-11, which has high affinity for GalR2 and GalR3, on Ca2+ influx through voltage-dependent Ca2+ channels in cultured myenteric neurons. Myenteric neurons were loaded with fluo-4 and depolarized by high K+ concentration to activate voltage-dependent Ca2+ channels. Intracellular Ca2+ levels were quantified with confocal microscopy. Galanin 1-16 (0.01-1 microM) inhibited the depolarization-evoked Ca2+ increase in a dose-dependent manner with an EC(50) of 0.172 microM. The selective GalR1 antagonist, RWJ-57408 (10 microM), blocked the Galanin 1-16 (1 microM)-mediated inhibition of voltage-dependent Ca2+ channel. By contrast, the GalR2/GalR3 agonist, Galanin 2-11 did not affect the K+-evoked Ca2+ influx in myenteric neurons. GalR1 immunoreactivity was localized solely to myenteric neurons in culture, as previously observed in intact tissue. These findings indicate that the inhibition of depolarization-evoked Ca2+ influx in myenteric neurons in culture is mediated by GalR1 and confirm the presence of functional GalR1 in the myenteric plexus. This is consonant with the hypothesis that GalR1 mediates Galanin inhibition of transmitter release from myenteric neurons.
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identification of Galanin Receptor 1 on excitatory motor neurons in the guinea pig ileum
2005Co-Authors: Stefania Guerrini, Laura Anselmi, E Cervio, A Agazzi, R Vicini, A Dellabianca, J R Reeve, M ToniniAbstract:Exogenously administered Galanin inhibits cholinergic transmission to the longitudinal muscle and reduces peristaltic efficiency in the guinea pig ileum with a mechanism partially mediated by gala- nin Receptor 1 (GAL-R1). We investigated the effect of exogenous Galanin 1-16, which has high affinity for GAL-R1, on the ascending excitatory reflex of the cir- cular muscle elicited by radial distension in isolated segments of guinea pig ileum. We used a three-com- partment bath that allows dissecting the ascending pathway into the oral (site of excitatory motor neu- rons), intermediate (site of ascending interneurons) and caudal compartment (site of intrinsic primary afferent neurons). Galanin 1-16 (0.3-3 lmol L )1 ) applied to the oral compartment inhibited in a con- centration-dependent manner the ascending excitato- ry reflex elicited by the wall distension in the caudal compartment. This effect was antagonized by the GAL-R1 antagonist, RWJ-57408 (1 and 10 lmol L )1 ). By contrast, Galanin 1-16 was ineffective when added to the intermediate or caudal compartment up to 3 lmol L )1 . GAL-R1 immunoreactive neurons did not contain neuron-specific nuclear protein, a marker for intrinsic primary afferent neurons. These findings indicate that GAL-R1s are present on motor neurons responsible for the ascending excitatory reflex, but not on ascending interneurons and intrinsic primary afferent neurons.
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role of Galanin Receptor 1 in gastric motility in rat
2004Co-Authors: Stephania Guerrini, Joseph R Reeve, Laura Anselmi, E Cervio, Helen E Raybould, A Agazzi, M Tonini, Catia SterniniAbstract:Abstract Galanin actions are mediated by distinctGalanin Receptors (GAL-R), GAL-R1, -R2 and -R3. Weinvestigated the role of GAL-R1 in gastric motility andthe expression of GAL-R1 in the rat stomach. In vivo,in urethane-anaesthetized rats, Galanin (equipotent forall GAL-Rs) induced a short inhibition of gastricmotility, followed by increase in tonic and phasicgastric motility; the latter was significantly reducedby the GAL-R1 antagonist, RWJ-57408. Galanin 1–16(high affinity for GAL-R1 and -R2) induced a long-lasting decrease of intragastric pressure, which wasnot modified by RWJ-57408. In vitro, Galanin andGalanin 1–16 induced increase of intragastric pressurethat was not affected by RWJ-57408. Tetrodotoxin(TTX) did not suppress the Galanin excitatory effect,whereas the effect of Galanin 1–16 on gastric contrac-tion was increased by TTX- or N-nitro-L-arginine, aninhibitor of nitric oxide synthase. GAL–R1 immuno-reactivity was localized to cholinergic and tachykin-ergic neurons and to neurons immunoreactive fornitric oxide synthase or vasoactive intestinal poly-peptide. This study suggests that an extrinsic GAL-R1pathway mediates the Galanin excitatory action,whereas an extrinsic, non GAL-R1 pathway is likely tomediate the Galanin inhibitory effect in vivo. GAL-R1intrinsic neurons do not appear to play a major role inthe control of gastric motility.Keywords enteric pathways, excitatory neurons,extrinsic pathways, inhibitory neurons, intragastricpressure.
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role of Galanin Receptor 1 in peristaltic activity in the guinea pig ileum
2004Co-Authors: Catia Sternini, Laura Anselmi, S Guerrini, E Cervio, T PhamAbstract:Abstract Galanin effects are mediated by distinct Receptors, Galanin Receptor 1 (GAL-R1), GAL-R2 and GAL-R3. Here, we analyzed 1) the role of GAL-R1 in cholinergic transmission and peristalsis in the guinea-pig ileum using longitudinal muscle–myenteric plexus preparations and intact segments of the ileum in organ bath, and 2) the distribution of GAL-R1 immunoreactivity in the myenteric plexus with immunohistochemistry and confocal microscopy. Galanin inhibited electrically stimulated contractions of longitudinal muscle–myenteric plexus preparations with a biphasic curve. Desensitization with 1 μM Galanin suppressed the high potency phase of the curve, whereas the GAL-R1 antagonist, RWJ-57408 (1 μM), inhibited the low potency phase. Galanin (3 μM) reduced the longitudinal muscle contraction and the peak pressure, and decreased the compliance of the circular muscle. All these effects were antagonized by RWJ-57408 (1 or 10 μM). RWJ-57408 (10 μM) per se did not affect peristalsis parameters in normal conditions, nor when peristalsis efficiency was reduced by partial nicotinic transmission blockade with hexamethonium. In the myenteric plexus, GAL-R1 immunoreactivity was localized to neurons and to fibers projecting within the plexus and to the muscle. GAL-R1 was expressed mostly by cholinergic neurons and by some neurons containing vasoactive intestinal polypeptide or nitric oxide synthase. This study indicates that Galanin inhibits cholinergic transmission to the longitudinal muscle via two separate Receptors; GAL-R1 mediates the low potency phase. The reduced peristalsis efficiency could be explained by inhibition of the cholinergic drive, whereas the decreased compliance is probably due to inhibition of descending neurons and/or to the activation of an excitatory muscular Receptor. Endogenous Galanin does not appear to affect neuronal pathways subserving peristalsis in physiologic conditions via GAL-R1.
Thomas E. Carey - One of the best experts on this subject based on the ideXlab platform.
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Galanin Receptor subtypes 1 and 2 as therapeutic targets in head and neck squamous cell carcinoma
2010Co-Authors: Takeharu Kanazawa, Kiyoshi Misawa, Thomas E. CareyAbstract:Importance of the field: Despite advances in the therapeutic approaches for head and neck squamous cell carcinoma (HNSCC) at some sites, no substantial improvement in treatment efficacy and survival has occurred over the past several decades. Recent application of molecular biology has focused on the importance of Galanin and its Receptors as potential therapeutic targets for HNSCC.Areas covered in this review: Our aim is to examine Galanin Receptor 1 (GALR1) and Galanin Receptor 2 (GALR2) as HNSCC therapeutic targets and explore opportunities and strategies for making use of GALR1 and GALR2 signaling.What the reader will gain: This review provides recent data about Galanin Receptor signaling and function in various cell types, especially HNSCC. Signaling through GALR1 induces cell cycle arrest and suppresses proliferation in HNSCC. Similar to GALR1, GALR2 not only induces cell cycle arrest but also apoptosis, which was not observed with GALR1.Take home messages: GALR1 and GALR2 act as tumor suppressors i...
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Galanin Receptor 1 has anti-proliferative effects in oral squamous cell carcinoma.
2005Co-Authors: Bradley S. Henson, Thomas E. Carey, Richard R. Neubig, Ilwhan Jang, Tetsuya Ogawa, Zhaocheng Zhang, Nisha J. D'silvaAbstract:In the United States, oral cancer accounts for more deaths annually than cervical cancer, leukemias, or Hodgkin's lymphoma. Studies have shown that aberrations of chromosome 18q develop with tumor progression and are associated with significantly decreased survival in head and neck cancer patients. The G-protein-coupled Receptor, Galanin Receptor 1 (GALR1), maps to this region of chromosome 18q. Although the role of GALR1 has been well characterized in neuronal cells, little is known regarding this Receptor in non-neuronal cells. In this study, the expression, mitogenic function, and signaling mechanism of GALR1 are investigated in normal and malignant oral epithelial cells. mRNA expression was determined via reverse transcriptase-PCR. Protein quantification was done via immunoblot analysis and enzyme-linked immunosorbent assay. For functional and signaling studies, an inhibitory antibody was generated to the N-terminal ligand binding domain of GALR1. GALR1 protein and mRNA expression and GAL secretion were detected at variable levels in immortalized human oral keratinocytes and human oropharyngeal squamous cell carcinoma cell lines. Upon competitive inhibition of GALR1, proliferation was up-regulated in immortalized and malignant keratinocytes. Furthermore, studies with the inhibitory antibody and U0126, the MAPK inhibitor, show that GALR1 inhibits proliferation in immortalized and malignant keratinocytes by inactivating the MAPK pathway. GALR1s inhibitory effects on proliferation in epithelial cells raises the possibility that inactivation or disregulation of this Receptor can lead to uncontrolled proliferation and neoplastic transformation.
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cloning and expression of the human Galanin Receptor 1 in head and neck cancer cells
2004Co-Authors: Takeharu Kanazawa, Kiyoshi Misawa, Yuki Misawa, Pavan K Kommareddi, Jairo A Matthews, Andrew Cole, Tetsuya Tono, Nisha J Dsilva, Thomas E. CareyAbstract:1864 We previously reported that loss of chromosome 18q develops with tumor progression and is associated with significantly decreased survival in head and neck cancer patients. Loss of heterozygosity (LOH) on 18q occurs in 50-75% of head and neck squamous cell carcinomas (HNSCC). The most common region of loss affecting 75% of HNSCC cell lines is centered on the microsatellite marker D18S70 in band 18q23. These results indicate the possible locus of a tumor suppressor gene in this area. One gene located within the common region of loss is Galanin Receptor type 1 (GALR 1). GALRs are members of G-protein coupled Receptors, and there are three Galanin Receptors. GALR1 and GALR3 are reported to signal via the Gi/G0 pathway whereas GALR2 signals via G12/13. Previous studies have shown that Galanin and its Receptors mediate diverse physiological activities such as release of gastrin and stomach acid, and neurotransmitter and hormone release in the peripheral and central nervous system. However, the function and signaling of GALRs, especially GALR1 in HNSCC, is not fully understood. We postulated that GALR1 might function as a tumor suppressor gene by regulating cell growth. In this study, we established stable clones expressing GALR1 to assess the function of GALR1. The full length GALR1 gene was isolated from a human brain cDNA library by polymerase chain reaction (PCR) under optimized conditions. The resulting PCR product was cloned into the TA cloning vector that contains the cytomegalovirus (CMV) promoter (pCMV-GALR1). The vectors were sequenced by the University of Michigan DNA sequencing Core. The human laryngeal carcinoma cell line HEp-2 that does not express GALR1 was transduced with pCMV-GALR1, and stable clones were selected in G418. The expression of GALR1 was determined by western blotting. Compared with parent cells and empty vector controls, the growth rate of the GALR1 expressing clones was inhibited. The inhibition of proliferation was proportional to the GALR1 expression level. Furthermore, there was an obvious change in the morphology of stable clones. Inhibition of proliferation and altered morphology of the stable clones are consistent with GALR1 functioning as a possible tumor suppressor gene. These results suggest that the GALR1 signaling pathway regulates cell replication and epithelial morphology. Loss of this function may allow unregulated cell proliferation and migration. This research is supported in part by the NIH NIDCR (5 R01 DE12477), by the NIH through the University of Michigan’s Head and Neck SPORE grant (1 P50 CA97248), by the NIH NCI through the University of Michigan’s Cancer Center Support grant (5 P30 CA46592), and by the Research Center Core grant NIH NIDCD (P30 DC05188).
Takeharu Kanazawa - One of the best experts on this subject based on the ideXlab platform.
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Galanin Receptor subtypes 1 and 2 as therapeutic targets in head and neck squamous cell carcinoma
2010Co-Authors: Takeharu Kanazawa, Kiyoshi Misawa, Thomas E. CareyAbstract:Importance of the field: Despite advances in the therapeutic approaches for head and neck squamous cell carcinoma (HNSCC) at some sites, no substantial improvement in treatment efficacy and survival has occurred over the past several decades. Recent application of molecular biology has focused on the importance of Galanin and its Receptors as potential therapeutic targets for HNSCC.Areas covered in this review: Our aim is to examine Galanin Receptor 1 (GALR1) and Galanin Receptor 2 (GALR2) as HNSCC therapeutic targets and explore opportunities and strategies for making use of GALR1 and GALR2 signaling.What the reader will gain: This review provides recent data about Galanin Receptor signaling and function in various cell types, especially HNSCC. Signaling through GALR1 induces cell cycle arrest and suppresses proliferation in HNSCC. Similar to GALR1, GALR2 not only induces cell cycle arrest but also apoptosis, which was not observed with GALR1.Take home messages: GALR1 and GALR2 act as tumor suppressors i...
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epigenetic inactivation of Galanin Receptor 1 in head and neck cancer
2008Co-Authors: Kiyoshi Misawa, Ilwhan Jang, Tetsuya Ogawa, Takeharu Kanazawa, Yo Ueda, Yuki Misawa, John C Brenner, Satoru TakebayashiAbstract:Purpose: One copy of the Galanin Receptor 1 ( GALR1 ) locus on 18q is often deleted and expression is absent in some head and neck squamous cell carcinoma (HNSCC) cell lines. To determine if loss of heterozygosity and hypermethylation might silence the GALR1 gene, promoter methylation status and gene expression were assessed in a large panel of HNSCC cell lines and tumors. Experimental Design: Promoter methylation of GALR1 in 72 cell lines and 100 primary tumor samples was analyzed using methylation-specific PCR. GALR1 expression and methylation status were analyzed further by real-time PCR and bisulfite sequencing analysis. Results: The GALR1 promoter was fully or partially methylated in 38 of 72 (52.7%) HNSCC cell lines but not in the majority 18 of 20 (90.0%) of nonmalignant lines. GALR1 methylation was also found in 38 of 100 (38%) primary tumor specimens. Methylation correlated with decreased GALR1 expression. In tumors, methylation was significantly correlated with increased tumor size ( P = 0.0036), lymph node status ( P = 0.0414), tumor stage ( P = 0.0037), cyclin D1 expression ( P = 0.0420), and p16 methylation ( P = 0.0494) and survival ( P = 0.045). Bisulfite sequencing of 36 CpG sites upstream of the transcription start site revealed that CpG methylation within transcription factor binding sites correlated with complete suppression of GALR1 mRNA. Treatment with trichostatin A and 5-azacytidine restored GALR1 expression. In UM-SCC-23 cells that have total silencing of GALR1 , exogenous GALR1 expression and stimulation with Galanin suppressed cell proliferation. Conclusions: Frequent promoter hypermethylation, gene silencing, association with prognosis, and growth suppression after reexpression support the hypothesis that GALR1 is a tumor suppressor gene in HNSCC.
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Galanin and Galanin Receptor type 1 suppress proliferation in squamous carcinoma cells activation of the extracellular signal regulated kinase pathway and induction of cyclin dependent kinase inhibitors
2007Co-Authors: Takeharu Kanazawa, Kiyoshi Misawa, Yo Ueda, Yuki Misawa, Pavan K Kommareddi, Toshihide Iwashita, Thankam S NairAbstract:Galanin Receptor 1 (GALR1) maps to a common region of 18q loss in head and neck squamous cell carcinomas and is frequently inactivated by methylation. To investigate effects of GALR1 and its signaling pathways, we stably expressed hemaglutinin-tagged GALR1 in a human oral carcinoma cell line (UM-SCC-1-GALR1) that expresses no endogenous GALR1. In transfected cells, Galanin induced activation of the extracellular-regulated protein kinase-1/2 (ERK1/2) and suppressed proliferation. Galanin stimulation mediated decreased expression of cyclin D1 and increased expression of the cyclin-dependent kinase inhibitors (CKI), p27(Kip1) and p57(Kip2). Pretreatment with the ERK1/2-specific inhibitor U0126 prevented these Galanin-induced effects. Phosphatidylinositol 3-kinase (PI3K) pathway activation did not differ in UM-SCC-1-GALR1 and UM-SCC-1-mock cells after Galanin treatment. Pertussis toxin and LY294002 inhibition demonstrated that Galanin and GALR1 induce ERK1/2 activation via Galphai, not the PI3K pathway-linked to the Gbetagamma subunit. Galanin and GALR1 also inhibit colony formation and tumor growth in vivo. Our results implicate GALR1, a Gi protein-coupled Receptor, as a tumor suppressor gene that inhibits cell proliferation via ERK1/2 activation.
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cloning and expression of the human Galanin Receptor 1 in head and neck cancer cells
2004Co-Authors: Takeharu Kanazawa, Kiyoshi Misawa, Yuki Misawa, Pavan K Kommareddi, Jairo A Matthews, Andrew Cole, Tetsuya Tono, Nisha J Dsilva, Thomas E. CareyAbstract:1864 We previously reported that loss of chromosome 18q develops with tumor progression and is associated with significantly decreased survival in head and neck cancer patients. Loss of heterozygosity (LOH) on 18q occurs in 50-75% of head and neck squamous cell carcinomas (HNSCC). The most common region of loss affecting 75% of HNSCC cell lines is centered on the microsatellite marker D18S70 in band 18q23. These results indicate the possible locus of a tumor suppressor gene in this area. One gene located within the common region of loss is Galanin Receptor type 1 (GALR 1). GALRs are members of G-protein coupled Receptors, and there are three Galanin Receptors. GALR1 and GALR3 are reported to signal via the Gi/G0 pathway whereas GALR2 signals via G12/13. Previous studies have shown that Galanin and its Receptors mediate diverse physiological activities such as release of gastrin and stomach acid, and neurotransmitter and hormone release in the peripheral and central nervous system. However, the function and signaling of GALRs, especially GALR1 in HNSCC, is not fully understood. We postulated that GALR1 might function as a tumor suppressor gene by regulating cell growth. In this study, we established stable clones expressing GALR1 to assess the function of GALR1. The full length GALR1 gene was isolated from a human brain cDNA library by polymerase chain reaction (PCR) under optimized conditions. The resulting PCR product was cloned into the TA cloning vector that contains the cytomegalovirus (CMV) promoter (pCMV-GALR1). The vectors were sequenced by the University of Michigan DNA sequencing Core. The human laryngeal carcinoma cell line HEp-2 that does not express GALR1 was transduced with pCMV-GALR1, and stable clones were selected in G418. The expression of GALR1 was determined by western blotting. Compared with parent cells and empty vector controls, the growth rate of the GALR1 expressing clones was inhibited. The inhibition of proliferation was proportional to the GALR1 expression level. Furthermore, there was an obvious change in the morphology of stable clones. Inhibition of proliferation and altered morphology of the stable clones are consistent with GALR1 functioning as a possible tumor suppressor gene. These results suggest that the GALR1 signaling pathway regulates cell replication and epithelial morphology. Loss of this function may allow unregulated cell proliferation and migration. This research is supported in part by the NIH NIDCR (5 R01 DE12477), by the NIH through the University of Michigan’s Head and Neck SPORE grant (1 P50 CA97248), by the NIH NCI through the University of Michigan’s Cancer Center Support grant (5 P30 CA46592), and by the Research Center Core grant NIH NIDCD (P30 DC05188).
Marina R Picciotto - One of the best experts on this subject based on the ideXlab platform.
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Galanin induced decreases in nucleus accumbens striatum excitatory postsynaptic potentials and morphine conditioned place preference require both Galanin Receptor 1 and Galanin Receptor 2
2013Co-Authors: Emily B Einstein, Yukiko Asaka, Mark F Yeckel, Michael J Higley, Marina R PicciottoAbstract:The neuropeptide Galanin has been shown to alter the rewarding properties of morphine. To identify potential cellular mechanisms that might be involved in the ability of Galanin to modulate opiate reward, we measured excitatory postsynaptic potentials (EPSPs), using both field and whole-cell recordings from striatal brain slices extracted from wild-type mice and mice lacking specific Galanin Receptor (GalR) subtypes. We found that Galanin decreased the amplitude of EPSPs in both the dorsal striatum and nucleus accumbens. We then performed recordings in slices from knockout mice lacking either the GalR1 or GalR2 gene, and found that the ability of Galanin to decrease EPSP amplitude was absent from both mouse lines, suggesting that both Receptor subtypes are required for this effect. In order to determine whether behavioral responses to opiates were dependent on the same Receptor subtypes, we tested GalR1 and GalR2 knockout mice for morphine conditioned place preference (CPP). Morphine CPP was significantly attenuated in both GalR1 and GalR2 knockout mice. These data suggest that mesolimbic excitatory signaling is significantly modulated by Galanin in a GalR1-dependent and GalR2-dependent manner, and that morphine CPP is dependent on the same Receptor subtypes.
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Galanin negatively modulates opiate withdrawal via Galanin Receptor 1
2012Co-Authors: Fiona E Holmes, Tiina P. Iismaa, John Shine, Emily B Einstein, Marina R Picciotto, Athena Armenaki, David Wynick, Venetia ZachariouAbstract:The neuropeptide Galanin has been shown to modulate opiate dependence and withdrawal. These effects could be mediated via activation of one or more of the three distinct G protein-coupled Receptors, namely Galanin Receptors 1 (GalR1), 2 (GalR2), and 3 (GalR3). In this study, we used several transgenic mouse lines to further define the mechanisms underlying the role played by Galanin and its Receptors in the modulation of morphine dependence. First, transgenic mice expressing β-galactosidase under the control of the Galanin promoter were used to assess the regulation of Galanin expression in response to chronic morphine administration and withdrawal. Next, the behavioral responses to chronic morphine administration and withdrawal were tested in mice that over-express Galanin, lack the GalR1 gene, or lack the GalR2 gene. Transgenic and matched wild-type mice were given increasing doses of morphine followed by precipitation of withdrawal by naloxone and behavioral responses to withdrawal were assessed. Both morphine administration and withdrawal increased Galanin gene transcription in the locus coeruleus (LC). Increasing Galanin levels in the brain reduced signs of opiate withdrawal. Mice lacking GalR1 undergo more severe opiate withdrawal, whereas mice lacking GalR2 show no significant difference in withdrawal signs, compare with matched wild-type controls. Opiate administration and withdrawal increase Galanin expression in the LC. Galanin opposes the actions of morphine which leads to opiate dependence and withdrawal, an effect that is mediated via GalR1.
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the Galanin Receptor 1 gene associates with tobacco craving in smokers seeking cessation treatment
2011Co-Authors: Adriana Lori, Marina R Picciotto, Yilang Tang, Stephanie S Omalley, Karen N Conneely, Joseph F CubellsAbstract:Craving for tobacco is a major challenge for people with nicotine dependence (ND) who try to quit smoking. Galanin (GAL) and its Receptors (GALRs) can alter addiction-related behaviors and are therefore good candidates for modulators of behavioral parameters associated with smoking. We performed a genetic association study in 486 subjects (432 European American, EA) recruited for smoking cessation trials. Twenty-six candidate genes for ND-related phenotypes were selected based on the literature. Subjects were assessed using the Minnesota Withdrawal Scale (MWS), which included a specific item for craving, the Fagerstrom Scale of Nicotine Dependence (FTND), and other ND-related instruments. One single-nucleotide polymorphism (SNP) in GALR1, rs2717162, significantly associated with severity of craving in EA samples (p=6.48 × 10−6) and in the combined sample (p=9.23 × 10−6). Individuals with TT and TC genotypes had significantly higher craving scores than CC subjects. We also observed that SNPs in the CHRNA5 locus, rs16969968 and rs684513, which have been associated with ND-related phenotypes in previous studies, were nominally associated with FTND scores, although these results did not meet Bonferroni-adjusted criteria for experiment-wide significance. Our findings suggest that variation at GALR1 associates with differences in the severity of past craving for tobacco among smokers motivated to quit. Taken together with preclinical evidence, these results, if replicated, suggest that GAL and GALRs may be useful therapeutic targets for the pharmacological treatment of ND. Our results also confirm previously reported associations between variation at CHRNA5 and ND.
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Galanin Receptor 1 gene expression is regulated by cyclic amp through a creb dependent mechanism
2008Co-Authors: Venetia Zachariou, Dan Georgescu, Leena Kansal, Priscilla Merriam, Marina R PicciottoAbstract:The Galanin Receptor-1 (GalR1) protein belongs to a family of G protein-coupled Receptors for the neuropeptide Galanin (GalR1, GalR2 and GalR3) distributed throughout the central and peripheral nervous system. Activation of Galanin Receptors by their ligands results in increased feeding, impaired learning, enhanced opiate analgesia and decreased opiate place preference. We have shown that opiate withdrawal, which is known to increase levels of cAMP in the locus coeruleus (LC), results in an increase in the number of Galanin binding sites and the level of GalR1 mRNA in the LC. We have isolated a 3.6-kb fragment 5′ of the inititiation codon of the mouse GalR1 gene and generated a series of deletion mutations of this fragment driving expression of luciferase for use in transient transfection assays in PC12 and Cath.a cell lines. Treatment with forskolin, but not dideoxyforskolin, up-regulates GalR1 transcription, likely through elevation of cAMP levels. The region between − 1050 and − 700 base pairs upstream of exon one is necessary both for basal activity of the GalR1 promoter and for forskolin-mediated increases in transcription. The forskolin effect can be blocked by simultaneous mutation of a CRE-like site and a CRE/DRE-like site, but not mutation of either site alone. Gel shift and super-shift experiments demonstrate that the transcription factor CREB can bind to both sites and is likely to be responsible for the cAMP-mediated increase in GalR1 promoter activity. This study provides a molecular mechanism for the increased GalR1 expression in the LC seen following opiate withdrawal.
Catia Sternini - One of the best experts on this subject based on the ideXlab platform.
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Galanin inhibition of voltage dependent ca2 influx in rat cultured myenteric neurons is mediated by Galanin Receptor 1
2009Co-Authors: Laura Anselmi, Catia Sternini, Salvatore L Stella, Nicholas C BrechaAbstract:Galanin activates three Receptors, the Galanin Receptor 1 (GalR1), GalR2, and GalR3. In the gastrointestinal tract, GalR1 mediates the Galanin inhibition of cholinergic transmission to the longitudinal muscle and reduction of peristalsis efficiency in the small intestine. Galanin has also been shown to inhibit depolarization-evoked Ca2+ increases in cultured myenteric neurons. Because GalR1 immunoreactivity is localized to cholinergic myenteric neurons, we hypothesized that this inhibitory action of Galanin on myenteric neurons is mediated by GalR1. We investigated the effect of Galanin 1-16, which has high affinity for GalR1 and GalR2, in the presence or absence of the selective GalR1 antagonist, RWJ-57408, and of Galanin 2-11, which has high affinity for GalR2 and GalR3, on Ca2+ influx through voltage-dependent Ca2+ channels in cultured myenteric neurons. Myenteric neurons were loaded with fluo-4 and depolarized by high K+ concentration to activate voltage-dependent Ca2+ channels. Intracellular Ca2+ levels were quantified with confocal microscopy. Galanin 1-16 (0.01-1 microM) inhibited the depolarization-evoked Ca2+ increase in a dose-dependent manner with an EC(50) of 0.172 microM. The selective GalR1 antagonist, RWJ-57408 (10 microM), blocked the Galanin 1-16 (1 microM)-mediated inhibition of voltage-dependent Ca2+ channel. By contrast, the GalR2/GalR3 agonist, Galanin 2-11 did not affect the K+-evoked Ca2+ influx in myenteric neurons. GalR1 immunoreactivity was localized solely to myenteric neurons in culture, as previously observed in intact tissue. These findings indicate that the inhibition of depolarization-evoked Ca2+ influx in myenteric neurons in culture is mediated by GalR1 and confirm the presence of functional GalR1 in the myenteric plexus. This is consonant with the hypothesis that GalR1 mediates Galanin inhibition of transmitter release from myenteric neurons.
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role of Galanin Receptor 1 in gastric motility in rat
2004Co-Authors: Stephania Guerrini, Joseph R Reeve, Laura Anselmi, E Cervio, Helen E Raybould, A Agazzi, M Tonini, Catia SterniniAbstract:Abstract Galanin actions are mediated by distinctGalanin Receptors (GAL-R), GAL-R1, -R2 and -R3. Weinvestigated the role of GAL-R1 in gastric motility andthe expression of GAL-R1 in the rat stomach. In vivo,in urethane-anaesthetized rats, Galanin (equipotent forall GAL-Rs) induced a short inhibition of gastricmotility, followed by increase in tonic and phasicgastric motility; the latter was significantly reducedby the GAL-R1 antagonist, RWJ-57408. Galanin 1–16(high affinity for GAL-R1 and -R2) induced a long-lasting decrease of intragastric pressure, which wasnot modified by RWJ-57408. In vitro, Galanin andGalanin 1–16 induced increase of intragastric pressurethat was not affected by RWJ-57408. Tetrodotoxin(TTX) did not suppress the Galanin excitatory effect,whereas the effect of Galanin 1–16 on gastric contrac-tion was increased by TTX- or N-nitro-L-arginine, aninhibitor of nitric oxide synthase. GAL–R1 immuno-reactivity was localized to cholinergic and tachykin-ergic neurons and to neurons immunoreactive fornitric oxide synthase or vasoactive intestinal poly-peptide. This study suggests that an extrinsic GAL-R1pathway mediates the Galanin excitatory action,whereas an extrinsic, non GAL-R1 pathway is likely tomediate the Galanin inhibitory effect in vivo. GAL-R1intrinsic neurons do not appear to play a major role inthe control of gastric motility.Keywords enteric pathways, excitatory neurons,extrinsic pathways, inhibitory neurons, intragastricpressure.
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role of Galanin Receptor 1 in peristaltic activity in the guinea pig ileum
2004Co-Authors: Catia Sternini, Laura Anselmi, S Guerrini, E Cervio, T PhamAbstract:Abstract Galanin effects are mediated by distinct Receptors, Galanin Receptor 1 (GAL-R1), GAL-R2 and GAL-R3. Here, we analyzed 1) the role of GAL-R1 in cholinergic transmission and peristalsis in the guinea-pig ileum using longitudinal muscle–myenteric plexus preparations and intact segments of the ileum in organ bath, and 2) the distribution of GAL-R1 immunoreactivity in the myenteric plexus with immunohistochemistry and confocal microscopy. Galanin inhibited electrically stimulated contractions of longitudinal muscle–myenteric plexus preparations with a biphasic curve. Desensitization with 1 μM Galanin suppressed the high potency phase of the curve, whereas the GAL-R1 antagonist, RWJ-57408 (1 μM), inhibited the low potency phase. Galanin (3 μM) reduced the longitudinal muscle contraction and the peak pressure, and decreased the compliance of the circular muscle. All these effects were antagonized by RWJ-57408 (1 or 10 μM). RWJ-57408 (10 μM) per se did not affect peristalsis parameters in normal conditions, nor when peristalsis efficiency was reduced by partial nicotinic transmission blockade with hexamethonium. In the myenteric plexus, GAL-R1 immunoreactivity was localized to neurons and to fibers projecting within the plexus and to the muscle. GAL-R1 was expressed mostly by cholinergic neurons and by some neurons containing vasoactive intestinal polypeptide or nitric oxide synthase. This study indicates that Galanin inhibits cholinergic transmission to the longitudinal muscle via two separate Receptors; GAL-R1 mediates the low potency phase. The reduced peristalsis efficiency could be explained by inhibition of the cholinergic drive, whereas the decreased compliance is probably due to inhibition of descending neurons and/or to the activation of an excitatory muscular Receptor. Endogenous Galanin does not appear to affect neuronal pathways subserving peristalsis in physiologic conditions via GAL-R1.
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distribution of Galanin Receptor 1 immunoreactivity in the rat stomach and small intestine
2002Co-Authors: Thomas Pham, Stefania Guerrini, Helen Wong, Joseph R Reeve, Catia SterniniAbstract:Galanin affects gastrointestinal functions by activating different G protein–coupled Receptors. Here, we identified the sites of expression of the Galanin Receptor 1 (GAL-R1) subtype in the rat stomach and small intestine by using immunohistochemistry with an antibody raised to the third intracellular loop of rat GAL-R1 (GAL-R1Y225-238) and confocal microscopy. Antibody specificity was confirmed by (1) the detection of a band at approximately 70 kDa in Western blot of membranes from GAL-R1 transfected cells, (2) the cell surface staining of GAL-R1 transfected cells, which was not detected in control cells, and (3) the abolition of Western signal and tissue immunostaining by preadsorbing the antibody with the peptide used for immunization. GAL-R1 immunoreactivity was localized to the cell surface of enterochromaffin-like cells, and of myenteric and submucous neurons, and to fibers distributed to the plexuses, interconnecting strands, muscle layers, vasculature, and mucosa. A dense network of GAL-R1 immunoreactivity was observed in the deep muscular plexus in very close association with interstitial cells of Cajal visualized by c-kit immunostaining. In the ileum, 81.6% of GAL-R1 myenteric neurons and 70.7% of GAL-R1 submucosal neurons were substance P immunoreactive. Vasoactive intestinal polypeptide immunoreactivity was found in 48.3% of GAL-R1 submucosal neurons, but not in GAL-R1 myenteric neurons. These findings support the hypothesis that GAL-R1 mediates Galanin actions on gastrointestinal motility and secretion by modulating the release of other neurotransmitters and contributes to Galanin-induced inhibition of gastric acid secretion by means of the suppression of endogenous histamine release. J. Comp. Neurol. 450:292–302, 2002. © 2002 Wiley-Liss, Inc.
