title: Serotonin regulates contractile activity of the uterus in non-pregnant rabbits.
abstract: Serotonin (5-HT) can stimulate the cholinergic system of the uterus by indirect actions on the modulation of reflexes and a direct action on smooth muscles. We investigated the role of 5-HT in the regulation of the cholinergic activity in the uterine parts of non-pregnant rabbits. The right vagus or pelvic nerve and the left sympathetic trunk were stimulated by an electrical field, and the uterine contractile activity was evaluated by measuring the amplitude and frequency of slow wave electromyogram (EMG), with the surface of microelectrodes applied to the uterus bottom, body, and cervix, respectively. Double stimulation of the vagus or pelvic nerve and the sympathetic trunk increased the frequency and the amplitude of the slow wave EMG in all the uterine parts. Furthermore, the administration of exogenous 5-HT increased the vagus or pelvic induced EMG activity in all parts of the uterus. Overall our results demonstrate that 5-HT enhances the vagus contractile activity with a magnitude of the effect decreasing from the bottom to the cervix, whereas 5-HT enhances the pelvic nerve contractile functions with a magnitude of the response increasing from the bottom to the cervix. The administration of droperidol, a 5-HT3 and 4 receptor inhibitor, and spiperone, a 5-HT2 receptor antagonist, inhibited the effect of the serotoninergic fibers of the sympathetic trunk to increase the vagus and pelvic nerve EMG activity. These data suggest that 5-HT stimulation of the parasympathetic nerves results in the induction of uterine contraction via the activation of 5-HT2, 3, and 4 receptor subfamilies.
authors.affiliation: Central Research Institute of Gastroenterology, Shosse Enthusiasts 86, 111123 Moscow, Russian Federation.
authors.forename: Alla Edward
authors.initials: AE
authors.lastname: Lychkova
authors.affiliation: Department of Molecular Medicine and Medical Biotechnology, University of Naples Federico II, Via S. Pansini 5, 80131 Naples, Italy.
authors.forename: Valeria
authors.initials: V
authors.lastname: De Pasquale
authors.affiliation: Department of Veterinary Medicine and Animal Productions, University of Naples Federico II, Via F. Delpino 1, 80137 Naples, Italy.
authors.forename: Luigi
authors.initials: L
authors.lastname: Avallone
authors.affiliation: Central Research Institute of Gastroenterology, Shosse Enthusiasts 86, 111123 Moscow, Russian Federation.
authors.forename: Alexander Michael
authors.initials: AM
authors.lastname: Puzikov
authors.affiliation: Department of Molecular Medicine and Medical Biotechnology, University of Naples Federico II, Via S. Pansini 5, 80131 Naples, Italy. Electronic address: luigimichele.pavone@unina.it.
authors.forename: Luigi Michele
authors.initials: LM
authors.lastname: Pavone
mesh_terms: D000818:Animals; D002584:Cervix Uteri / Q000187:drug effects* / Q000378:metabolism; D005260:Female; D009119:Muscle Contraction / Q000187:drug effects*; D010275:Parasympathetic Nervous System / Q000187:drug effects / Q000378:metabolism; D011817:Rabbits; D011985:Receptors, Serotonin / Q000378:metabolism; D012701:Serotonin / Q000378:metabolism* / Q000494:pharmacology*
chemical_list: D011985:Receptors, Serotonin; D012701:Serotonin
keywords: Cholinergic system; Contraction; Serotonin; Serotonin receptors; Uterus