The Experts below are selected from a list of 126 Experts worldwide ranked by ideXlab platform
Natalie Kozyrev - One of the best experts on this subject based on the ideXlab platform.
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chronic contusion spinal cord injury impairs ejaculatory reflexes in male rats partial recovery by systemic infusions of dopamine d3 receptor agonist 7ohdpat
Journal of Neurotrauma, 2016Co-Authors: Natalie Kozyrev, Michael D Staudt, Arthur Brown, Lique M CoolenAbstract:Abstract Chronic spinal cord injury (SCI) causes major disruption of ejaculatory function in men. Ejaculation is a reflex and the spinal generator for ejaculatory reflexes in the rat has been located in the lumbosacral spinal cord. The effects of SCI on the rat spinal ejaculation generator and ejaculatory reflexes remain understudied. The first goal of the current study was to establish the effects of chronic SCI on the function of the spinal ejaculation generator. Male rats received a contusion injury of the spinal cord at spinal level T6–T7. Ejaculatory reflexes elicited by electrical stimulation of the dorsal penile nerve (DPN) were evaluated in injured and control rats at 4–6 weeks following SCI. SCI males demonstrated significant reductions in bursting of the Bulbocavernosus Muscle (BCM), an indicator for expulsion phase of ejaculation, and in seminal vesicle pressure (SVP) increases, an indicator for the emission phase of ejaculation, following DPN stimulation. Thus, contusion SCI resulted in long-t...
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activation of mu or delta opioid receptors in the lumbosacral spinal cord is essential for ejaculatory reflexes in male rats
PLOS ONE, 2015Co-Authors: Natalie Kozyrev, Lique M CoolenAbstract:Ejaculation is controlled by a spinal ejaculation generator located in the lumbosacral spinal cord, consisting in male rats of lumbar spinothalamic (LSt) cells and their inter-spinal projections to autonomic and motor centers. LSt cells co-express several neuropeptides, including gastrin releasing peptide (GRP) and enkephalin. We previously demonstrated in rats that GRP regulates ejaculation by acting within the lumbosacral spinal cord. In the present study, the hypothesis was tested that enkephalin controls ejaculation by acting on mu (MOR) or delta opioid receptors (DOR) in LSt target areas. Adult male rats were anesthetized and spinalized and received intrathecal infusions of vehicle, MOR antagonist CTOP (0.4 or 4 nmol), DOR antagonist (TIPP (0.4, 4 or 40 nmol), MOR agonist DAMGO (0.1 or 10 nmol), or DOR agonist deltorphin II (1.3 or 13 nmol). Ejaculatory reflexes were triggered by stimulation of the dorsal penile nerve (DPN) and seminal vesicle pressure and rhythmic contractions of the Bulbocavernosus Muscle were analyzed. Intrathecal infusion of MOR or DOR antagonists effectively blocked ejaculatory reflexes induced by DPN stimulation. Intrathecal infusion of DAMGO, but not deltorphin II triggered ejaculation in absence of DPN stimulation. Both MOR and DOR agonists facilitated ejaculatory reflexes induced by subthreshold DPN stimulation in all animals. Overall, these results support the hypothesis that enkephalin plays a critical role in the control of ejaculation in male rats. Activation of either MOR or DOR in LSt target areas is required for ejaculation, while MOR activation is sufficient to trigger ejaculation in the absence of sensory stimulation.
Ali A Shafik - One of the best experts on this subject based on the ideXlab platform.
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Physioanatomical relationship of the external anal sphincter to the Bulbocavernosus Muscle in the female
International Urogynecology Journal, 2007Co-Authors: Ahmed Shafik, Ismail A. Shafik, Olfat El Sibai, Ali A ShafikAbstract:Both external anal sphincter (EAS) and Bulbocavernosus Muscle (BCM) have been shown anatomically and physiologically to constitute one Muscle in males. We investigated the hypothesis that the EAS and BCM have similar anatomical pattern in females. The study consisted of cadaveric dissection, electromyographic recordings and inferior rectal nerve stimulation. Bulbocavernosus reflex action was performed in 16 healthy women before and after anesthetization of the EAS and BCM. The EAS extended forward across the perineal body and became continuous with the BCM in the labia majora. Glans clitoris (GC) or inferior rectal nerve stimulation effected synchronous EAS and BCM contractions with identical action potentials. GC stimulation while the EAS or BCM was anesthetized produced neither EAS nor BCM response. Similarly, stimulation of the anesthetized GC produced no EAS or BCM response. The BCM and EAS apparently constitute a single Muscle, which seems to play dual and yet synchronous roles in fecal control and sexual response.
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study of the effect of straining on the Bulbocavernosus Muscle with evidence of a straining Bulbocavernosus reflex and its clinical significance
International Urogynecology Journal, 2002Co-Authors: Ali A Shafik, Randa M Mostafa, Olfat ElsibaiAbstract:The Bulbocavernosus Muscle (BCM) surrounds the vaginal introitus and covers the vestibular bulb. Its role in erection is known. However, as it surrounds the vaginal introitus, it may also have a role in intravaginal pressure regulation and in the pathogenesis of uterovaginal prolapse. We investigated the effect of increased intra-abdominal pressure (IAP) on the BCM, aiming to assess its possible function in supporting the uterus, vagina and anorectum. The intrarectal (representative of the IAP) and intravaginal pressures were measured by manometric catheters in 19 healthy women volunteers (mean age 46.2 ± 10.4 years). The EMG activity of the BCM and its response to straining at different pressures were recorded by a concentric needle electrode. Two types of straining were tested: sudden momentary and slow sustained. The procedure was repeated in 11 of the women after individual anesthetization of the BCM, rectum and vagina. Sudden straining (coughing) produced a significant increase in intrarectal (P<0.0001) and intravaginal (P<0.0001) pressure as well as BCM EMG activity. Slow straining effected a similar but lower response: the BCM responded gradually with pressure elevation, whereas the latency exhibited a gradual decrease. The BCM did not react to straining after individual anesthetization of the BCM, vagina and rectum, but did respond to saline administration. The results were reproducible. BCM contraction on straining postulates a reflex relationship, which we call the ‘straining–Bulbocavernosus reflex’. We hypothesized that this reflex is evoked by straining and results in BCM contraction and closure of the vaginal introitus. The vagina is believed to become a closed cavity, counteracting the increased intra-abdominal pressure and the uterine tendency to prolapse. The high pressure in the closed vaginal cavity presumably supports the rectovaginal septum against the high intrarectal pressure, and is suggested to share in the prevention of rectocele. The role of BCM in the pathogenesis of uterovaginal prolapse and rectocele needs further study.
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Physioanatomic entirety of external anal sphincter with Bulbocavernosus Muscle.
Archives of andrology, 1999Co-Authors: Ali A ShafikAbstract:Stimulation of the glans penis evokes contraction of both the Bulbocavernosus Muscles (BCM) and the external anal sphincter (EAS). This synchronous contraction of the two Muscles led us to study their physioanatomic relationship and possible role in erection and ejaculation. Fifteen male cadavers were studied (8 neonatal deaths and 7 adults; mean age 48 years) by dissection. The Bulbocavernosus reflex action was performed in 12 healthy male volunteers (mean age 37 years) before and after anesthetizing the EAS. The response of the EAS and BCM to inferior rectal nerve stimulation was assessed in 6 men (mean age 41 years). The superficial fibers of the base loop of the EAS extended forward to the penile bulb where they were arranged into 3 groups: 1 median and 2 lateral. The median fibers, or the ''retractor penis Muscle," were found inserted into the corpora cavernosa and the lateral fibers, or the ''compressor bulbae Muscle," into the perineal membrane. Upon glans penis stimulation, both the EAS and BCM co...
Lique M Coolen - One of the best experts on this subject based on the ideXlab platform.
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chronic contusion spinal cord injury impairs ejaculatory reflexes in male rats partial recovery by systemic infusions of dopamine d3 receptor agonist 7ohdpat
Journal of Neurotrauma, 2016Co-Authors: Natalie Kozyrev, Michael D Staudt, Arthur Brown, Lique M CoolenAbstract:Abstract Chronic spinal cord injury (SCI) causes major disruption of ejaculatory function in men. Ejaculation is a reflex and the spinal generator for ejaculatory reflexes in the rat has been located in the lumbosacral spinal cord. The effects of SCI on the rat spinal ejaculation generator and ejaculatory reflexes remain understudied. The first goal of the current study was to establish the effects of chronic SCI on the function of the spinal ejaculation generator. Male rats received a contusion injury of the spinal cord at spinal level T6–T7. Ejaculatory reflexes elicited by electrical stimulation of the dorsal penile nerve (DPN) were evaluated in injured and control rats at 4–6 weeks following SCI. SCI males demonstrated significant reductions in bursting of the Bulbocavernosus Muscle (BCM), an indicator for expulsion phase of ejaculation, and in seminal vesicle pressure (SVP) increases, an indicator for the emission phase of ejaculation, following DPN stimulation. Thus, contusion SCI resulted in long-t...
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activation of mu or delta opioid receptors in the lumbosacral spinal cord is essential for ejaculatory reflexes in male rats
PLOS ONE, 2015Co-Authors: Natalie Kozyrev, Lique M CoolenAbstract:Ejaculation is controlled by a spinal ejaculation generator located in the lumbosacral spinal cord, consisting in male rats of lumbar spinothalamic (LSt) cells and their inter-spinal projections to autonomic and motor centers. LSt cells co-express several neuropeptides, including gastrin releasing peptide (GRP) and enkephalin. We previously demonstrated in rats that GRP regulates ejaculation by acting within the lumbosacral spinal cord. In the present study, the hypothesis was tested that enkephalin controls ejaculation by acting on mu (MOR) or delta opioid receptors (DOR) in LSt target areas. Adult male rats were anesthetized and spinalized and received intrathecal infusions of vehicle, MOR antagonist CTOP (0.4 or 4 nmol), DOR antagonist (TIPP (0.4, 4 or 40 nmol), MOR agonist DAMGO (0.1 or 10 nmol), or DOR agonist deltorphin II (1.3 or 13 nmol). Ejaculatory reflexes were triggered by stimulation of the dorsal penile nerve (DPN) and seminal vesicle pressure and rhythmic contractions of the Bulbocavernosus Muscle were analyzed. Intrathecal infusion of MOR or DOR antagonists effectively blocked ejaculatory reflexes induced by DPN stimulation. Intrathecal infusion of DAMGO, but not deltorphin II triggered ejaculation in absence of DPN stimulation. Both MOR and DOR agonists facilitated ejaculatory reflexes induced by subthreshold DPN stimulation in all animals. Overall, these results support the hypothesis that enkephalin plays a critical role in the control of ejaculation in male rats. Activation of either MOR or DOR in LSt target areas is required for ejaculation, while MOR activation is sufficient to trigger ejaculation in the absence of sensory stimulation.
V P Gangadharan - One of the best experts on this subject based on the ideXlab platform.
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spontaneous rectovaginal fistula and repair using Bulbocavernosus Muscle flap
Techniques in Coloproctology, 2001Co-Authors: K Chitrathara, D Namratha, V Francis, V P GangadharanAbstract:Spontaneous fistula between anorectum and vagina is extremely uncommon. Successful repair depends on etiology, location and the expertise of the surgeon. We report two cases of spontaneous stercoral perforation resulting in rectovaginal fistula (RVF). Both occurred in bedridden patients with fecal impaction. One patient was successfully repaired with a Bulbocavernosus (BC) flap interposition. Flap interposition prevents vaginal stenosis in repair of multiple RVF.
Claessens Frank - One of the best experts on this subject based on the ideXlab platform.
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A shortened tamoxifen induction scheme to induce CreER recombinase without side effects on the male mouse skeleton
Elsevier, 2017Co-Authors: Jardi Ferran, Laurent Michaël, Dubois Vanessa, Khalil Rougin, Deboel Ludo, Schollaert Dieter, Van Den Bosch Ludo, Decallonne Brigitte, Carmeliet Geert, Claessens FrankAbstract:The selective estrogen receptor modulator tamoxifen exerts estrogen agonistic or antagonistic actions on several tissues, including bone. The off-target effects of tamoxifen are one of the most widely recognized pitfalls of tamoxifen-inducible Cre recombinases (CreERs), potentially confounding the phenotypic findings. Still, the validation of tamoxifen induction schemes that minimize the side effects of the drug has not been addressed. Here, we compared the side effects on the skeleton and other androgen-responsive targets of a shortened tamoxifen regimen (2 doses of 190 mg/kg body weight by oral gavage) to a standard protocol (4 doses) and determined their efficiency in inducing CreER-mediated gene deletion. In addition, both a vehicle- and a 10-dose group, which served as a positive control for tamoxifen side effects, were also included. For this purpose, we generated male mice with a floxed androgen receptor (AR) and a neuron-specifically expressed CreER. Treatment with two doses of tamoxifen was the only regimen that did not diminish androgenic bioactivity, as assessed by both seminal vesicles and levator ani/Bulbocavernosus Muscle weights and serum testosterone concentrations. Similarly, trabecular and cortical femoral bone structure were dramatically altered by both the standard and high-dose protocols but not by the shortened version. Serum osteocalcin and bone-gene expression analyses confirmed the absence of effects on bone by 2 doses of tamoxifen. This protocol decreased AR mRNA levels efficiently and specifically in the nervous system. Thus, we optimized a protocol for tamoxifen-induced CreER gene deletion in mice without off-target effects on bone and male reproductive organs.status: publishe
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A shortened tamoxifen induction scheme to induce CreER recombinase without side effects on the male mouse skeleton
'Elsevier BV', 2017Co-Authors: Jardi Ferran, Laurent Michaël, Dubois Vanessa, Khalil Rougin, Deboel Ludo, Schollaert Dieter, Van Den Bosch Ludo, Decallonne Brigitte, Carmeliet Geert, Claessens FrankAbstract:The selective estrogen receptor modulator tamoxifen exerts estrogen agonistic or antagonistic actions on several tissues, including bone. The off-target effects of tamoxifen are one of the most widely recognized pitfalls of tamoxifen-inducible Cre recombinases (CreERs), potentially confounding the phenotypic findings. Still, the validation of tamoxifen induction schemes that minimize the side effects of the drug has not been addressed. Here, we compared the side effects on the skeleton and other androgen-responsive targets of a shortened tamoxifen regimen (2 doses of 190 mg/kg body weight by oral gavage) to a standard protocol (4 doses) and determined their efficiency in inducing CreER-mediated gene deletion. In addition, both a vehicle- and a 10-dose group, which served as a positive control for tamoxifen side effects, were also included. For this purpose, we generated male mice with a floxed androgen receptor (AR) and a neuron-specifically expressed CreER. Treatment with two doses of tamoxifen was the only regimen that did not diminish androgenic bioactivity, as assessed by both seminal vesicles and levator ani/Bulbocavernosus Muscle weights and serum testosterone concentrations. Similarly, trabecular and cortical femoral bone structure were dramatically altered by both the standard and high-dose protocols but not by the shortened version. Serum osteocalcin and bone-gene expression analyses confirmed the absence of effects on bone by 2 doses of tamoxifen. This protocol decreased AR mRNA levels efficiently and specifically in the nervous system. Thus, we optimized a protocol for tamoxifen-induced CreER gene deletion in mice without off-target effects on bone and male reproductive organs.publisher: Elsevier articletitle: A shortened tamoxifen induction scheme to induce CreER recombinase without side effects on the male mouse skeleton journaltitle: Molecular and Cellular Endocrinology articlelink: http://dx.doi.org/10.1016/j.mce.2017.05.012 content_type: article copyright: © 2017 Elsevier B.V. All rights reserved.status: publishe
