Activation by p-chloroamphetamine of the spinal ejaculatory pattern generator in anaesthetized male rats

• Published in: Neuroscience 2006-01, Vol.140 (3), p.1031-1040
• Main Authors: Stafford, S.A., Bowery, N.G., Tang, K., Coote, J.H.
• Format: Article
• Language: English
• Subjects: Action Potentials - drug effects; Action Potentials - physiology; Anesthetics, Intravenous - pharmacology; Animals; Biogenic Monoamines - physiology; Biological and medical sciences; Drug Interactions - physiology; Efferent Pathways - drug effects; Efferent Pathways - physiology; ejaculation; Ejaculation - drug effects; Ejaculation - physiology; Fundamental and applied biological sciences. Psychology; Hypogastric Plexus - drug effects; Hypogastric Plexus - physiology; Male; Neural Pathways - drug effects; Neural Pathways - physiology; p-Chloroamphetamine - pharmacology; Pelvic Floor - innervation; Pelvic Floor - physiology; Rats; Rats, Wistar; Receptors, Catecholamine - drug effects; Receptors, Catecholamine - physiology; Receptors, Serotonin - drug effects; Receptors, Serotonin - physiology; Serotonin Agents - pharmacology; sexual climax; Spinal Cord - drug effects; Spinal Cord - physiology; Synaptic Transmission - drug effects; Synaptic Transmission - physiology; Urethane - pharmacology; vas deferens; Vas Deferens - innervation; Vas Deferens - physiology; Vertebrates: nervous system and sense organs
• ISSN: 0306-4522; 1873-7544
• DOI: 10.1016/j.neuroscience.2006.02.039

In urethane-anesthetized male rats, a branch of the hypogastric nerve was shown, anatomically and electrophysiologically, to supply the vas deferens. Recordings from this nerve revealed a low level of tonic activity, which was predominantly efferent motor activity. Administration of p-chloroamphetamine i.v., elicited a rhythmic burst of neuronal activity, coherent with rhythmic pressure increases in the vas deferens and contractions of the bulbospongiosus muscles, which together comprise ejaculation. This response to p-chloroamphetamine was still present after complete transection of the spinal cord at T8–T9. These data indicate that p-chloroamphetamine is capable of activating the spinal neuronal circuits that generate the pattern of autonomic and somatic responses similar to those of sexual climax. Furthermore based on the best documented action of p-chloroamphetamine, the results suggest that the excitability of the pattern generator is regulated by serotonergic, dopaminergic or noradrenergic receptors in the lumbosacral spinal cord. We conclude this animal model will enable robust studies of the pharmacology and physiology of central neural mechanisms involved in ejaculation and sexual climax.