Oxytocinergic and serotonergic innervation of identified lumbosacral nuclei controlling penile erection in the male rat
Section snippets
Experimental procedures
The experiments were performed on 20 adult male Sprague–Dawley rats weighing 300–400 g (Charles River, Saint Aubin-les-Elbeuf, France). Animals were anaesthetized with ketamine intraperitoneally injected (150 mg/kg). In 17 rats, the left pelvic nerve was exposed through a suprapubic midline incision, and under the control of an operating microscope, cut, and its central end immersed in 1 μL of a solution of wheatgerm agglutinin–horseradish peroxidase (WGA–HRP, 25% in sterile water) for 60 min. Then
Retrograde labelling from the pelvic nerve
Neurons labelled by retrograde transport of WGA–HRP from the pelvic nerve were found in the L6 and S1 segments of the ipsilateral spinal cord and absent in the L5 segment. From a rough estimate, their number appeared to be greater in the L6 than in the S1 spinal cord. In the transverse plane labelled neurons were located in the intermediolateral column (i.e. the sacral parasympathetic nucleus, SPN) (Fig. 1A). In the longitudinal plane, labelled neurons formed a continuous band in the L6 and S1
Retrograde labelling of autonomic and somatic motoneurons in the spinal cord
Using retrograde labelling and immunocytochemistry, we showed that synapses occur between oxytocin- or 5-HT-immunoreactive fibres and identified lumbosacral autonomic and somatic motoneurons. At the ultrastructural level, the use of specific antibodies and the labelling of the same structures in several consecutive sections confirms that oxytocin and 5-HT labellings are not artifactual. Retrograde labelling from the pelvic nerve of neurons located in the intermediolateral cell column of the
Acknowledgements
The authors thank Dr K. E. McKenna for revising the manuscript.
References (55)
- et al.
Effects of oxytocin and vasopressin on thoracic sympathetic preganglionic neurones in the cat
Brain Res. Bull.
(1984) - et al.
Electrophysiological evidence for oxytocin receptors on sympathetic preganglionic neurones – an in vitro study on the neonatal rat
Brain Res.
(1995) - et al.
The influence of the paraventriculo-spinal pathway, and oxytocin and vasopressin on sympathetic preganglionic neurones
Brain Res.
(1982) - et al.
Neural control of penile erection
Urol. Clin. North Am.
(1995) - et al.
Preganglionic neurons in the sacral spinal cord of the rat: an HRP study
Neurosci. Lett.
(1979) - et al.
Electromyographic analysis of male rat perineal muscles during copulation and reflexive erections
Physiol. Behav.
(1991) - et al.
Supraspinal influences on the penile reflexes of the male rat: a comparison of the effects of copulation, spinal transection and cortical spreading depression
Horm. Behav.
(1979) - et al.
Effects of intrathecal administration of 8-OH-DPAT on genital reflexes and mating behavior in male rats
Physiol. Behav.
(1990) - et al.
Autoradiographic mapping of 5-HT1, 5-HT1A, 5-HT1B and 5-HT2 receptors in the rat spinal cord
Brain Res.
(1991) - et al.
Lesions of the nucleus paragigantocellularis alter ex copula penile reflexes
Brain Res.
(1992)
Serotonergic neurotoxic lesions facilitate male sexual reflexes
Pharmac. Biochem. Behav.
Stimulation of spinal serotonergic receptors facilitates seminal emission and suppresses penile erectile reflexes
Brain Res.
Effects of intrathecal and systemic administration of buspirone on genital reflexes and mating behavior in male rats
Pharmac. Biochem. Behav.
Electrical stimulation of the dorsal nerve of the penis evokes reflex tonic erections of the penile body and reflex ejaculatory responses in the spinal rat
J. Urol.
Crossing dendrites may be a substrate for synchronized activation of penile motoneurons
Brain Res.
Oxytocinergic innervation of the rat spinal cord
Brain Res.
Oxytocin acts at V1 receptors to excite sympathetic preganglionic neurones in neonate rat spinal cord in vitro
Brain Res.
Distribution of serotonin-immunoreactivity in the central nervous system of the rat cell bodies and terminals
Neuroscience
Convergence of serotonin-, enkephalin- and substance P-like immunoreactive afferent fibers on single pudendal motoneurons in Onuf's nucleus of the cat: a light microscope study combining the triple immunocytochemical staining technique with the retrograde HRP-tracing method
Brain Res.
Autoradiographic localization of 5-hydroxytryptamine1A, 5-hydroxytryptamine1B and 5-hydroxytryptamine1C/2 binding sites in the rat spinal cord
Neuroscience
The effect of 5-HTP on the static fusimotor activity and the tonic stretch reflex of an extensor muscle
Brain Res.
Three bulbospinal pathways from the rostral medulla of the cat: an autoradiographic study of pain modulating systems
J. comp. Neurol.
The origin of descending pathways in the dorsolateral funiculus of the spinal cord of the cat and rat: further studies on the anatomy of pain modulation
J. comp. Neurol.
Endogenous pain control systems: brainstem spinal pathways and endorphin circuitry
A. Rev. Neurosci.
Intra- and extrahypothalamic vasopressin and oxytocin pathways in the rat
Cell Tiss. Res.
Pudendal motor and premotor neurons in the male rat: a WGA transneuronal study
J. comp. Neurol.
Cited by (108)
The impact of erectile dysfunction on infertility and its treatment
2021, Psychological and Medical Perspectives on Fertility Care and Sexual HealthNormal male sexual function: Emphasis on orgasm and ejaculation
2015, Fertility and SterilityCitation Excerpt :Cerebrally controlled penile erections are induced through erotic visual stimuli or thoughts. The main cerebral structures involved in erection are contained within the medial preoptic area (MPOA) and paraventricular nucleus (PVN) in the hypothalamus (6). Dopamine is the most important brain neurotransmitter for erection, likely through its stimulation of oxytocin release (7).
The role of oxytocin in male and female reproductive behavior
2015, European Journal of PharmacologyCitation Excerpt :A series of tract-tracing studies, in which pseudorabies viruses were injected into the corpus cavernosum, penile muscles, epididymis and prostate of male rats, showed that the PVN was connected to each type of tissue (Gerendai et al., 2001; Marson and McKenna, 1996; Marson et al., 1993; Orr and Marson, 1998; Tang et al., 1998) putatively via the sacral parasympathetic nucleus (Tang et al., 1999). Varicosities containing OT or neurophysin (a carrier protein indicating the presence of either OT or AVP (Breslow and Burman, 1990)) have been found in close apposition to neurons in the sacral parasympathetic nucleus, ventral horn, and dorsal gray commissure that directly or indirectly control the genitals (Tang et al., 1998; Veronneau-Longueville et al., 1999; Wagner and Clemens, 1993). The (putatively OTergic) paraventricular neurons projecting to the spinal cord also provide collateral projections to the nucleus paragigantocellularis in the brainstem, which exerts a tonic serotonergic inhibition of penile reflexes (Bancila et al., 2002; Normandin and Murphy, 2011).
Moderate Role of Oxytocin in the Pro-Ejaculatory Effect of the 5-HT<inf>1A</inf> Receptor Agonist 8-OH-DPAT
2015, Journal of Sexual MedicineNeuropeptides and central control of sexual behaviour from the past to the present: A review
2013, Progress in Neurobiology