Visceral and postural reflexes evoked by genital stimulation in urethane-anesthetized female rats (original) (raw)
Related papers
Somato-motor components of the pelvic and pudendal nerves of the female rat
Brain Research, 1989
The efferent innervation of the pelvic and pudendal nerves was characterized in this study by identifying the muscles activated by electrical stimulation of the nerves distal to the point at which they bifurcate from the L6-S 1 trunk. Pelvic nerve electrical stimulation produced EMG-monitored contraction of the ipsilaterai ilio-and pubococcygeus muscles, which was abolished by cutting one ('muscular') branch of the bifurcated nerve. (This 'muscular' branch receives proprioceptive input activated by tail displacement, whereas the other, 'viscero-cutaneous' branch receives sensory innervation from the midline perineal region.)Pudendal nerve electrical stimulation produced contraction of the coccygeus, external anal sphincter, and ischiocavernosus muscles. Movements of the orifice and wall of the vagina were directly visualized during electrical stimulation of the two nerves. Intravaginai pressure measured by balloon was increased by pelvic nerve stimulation and decreased by pudendal nerve stimulation. Reflexive contraction of the ilio-en pubococcygeus muscles was produced by mechanostimulation of the perineum, clitoral sheath and distal vagina. This response was abolished by gentle cervical mechanostimulation. One implication of this finding is that passage of the fetuses through the cervix during parturition may relax the ilio-and pubococcygeus muscles, thereby facilitating delivery.
Suppression of a spinal and a cranial nerve reflex by vaginal or rectal probing in rats
Brain Research, 1971
In a previous study, vaginal or rectal probing facilitated the lordosis response to palpation of the flanks and the perineurn in rats 10. In that study, vaginal or rectal probing alone induced a marked immobilization, in which the rat could be slid along the surface of a table, stiff-legged, by pushing on the probe. Furthermore, the vibrissae were held stiffly in place, instead of twitching rhythmically as they do when rats show exploratory behavior. The present study was undertaken to analyze the nature of this behavioral inhibition induced by such probing. The possible suppressive action of vaginal or rectal probing on two different reflexes was studied: leg-withdrawal response to foot pinch, and unilateral vibrissa retraction response to ipsilateral ear pinch. The vibrissa or leg-withdrawal reflexes were elicited ipsilaterally by pinching the base of the ear or the foot, respectively, with fine mouse-tooth forceps. Sprague-Dawley rats (derived from Columbia strain, Carom Research Laboratories, Wayne, N.J.) weighing 300-400 g, and either ovariectomized more than 6 weeks previously or intact, were injected with Equithesin (which contains a combination of pentobarbital, chloral hydrate, and magnesium sulfate, 0.15-0.18 ml/100 g body wt. ; Jensen-Salsbery, Kansas City, Mo.) supplemented as necessary to prevent spontaneous movement and head turning in response to ear pinch. Electrophysiological recordings were obtained by photographing, with a Polaroid CRO (cathode ray oscilloscope) camera, EMGs displayed on a Tektronix 564 4-beam storage CRO at very slow speed. EMGs were obtained by implanting twisted pairs of stainless steel wire (0.01 in. diameter), insulated except at the tips, into muscles of the lateral surface of the leg or the vibrissa pad through slits in the skin, and fastening the wires to the external skin surface with sutures. The rats were placed on their side, with no mechanical restraints. Muscle potentials were amplified by Grass 7P3 amplifiers (0.5 amplitude filters at 10 c/sec and 0.5 kc/sec) through Grass HIP-51A high impedance cathode follower probes, and then filtered further through Kopf spike filters. Occasional slow fluctuations in the baselines originated in the CRO and were artifactual. Two CRO channels were operated to provide appropriate signal marking as shown in the figures. A microswitch taped to a mouse-tooth forceps closed a battery circuit monitored by the CRO, thus indicating when pinch was applied. Except as otherwise indicated, the rat was prevented from sliding forward during probing by taping the tail into a loop, passing a cord through the loop, and attaching the cord to a rigid support or a spring scale. Stimulation was applied with a 1 ml tuberculin syringe plunger using a firm force (50-800 g, measured by holding the tail loop by the hook of a scale and then probing). Probing against the vaginal cervix suppressed markedly or completely (a) the
Response of the internal reproductive organs to clitoral stimulation: The clitorouterine reflex
International journal of impotence research, 2004
We investigated hypothesis that uterine erection, elevation and enlargement during sexual response are reflex and result from penis buffeting the glans clitoris (GC). In 23 healthy women, two recording electrodes were applied to the uterine mucosa and one to cervix uteri (CU). GC was stimulated electrically and mechanically by pencil electrode. The uterine and CU pressures were measured. Tests were repeated after anesthetization of the uterus or GC. Uterine electrodes recorded slow waves, followed by random bursts of ...
International Journal of Impotence Research, 2000
The objective of this present study is to establish a model in the rat for the study of female clitoral and vaginal vascular changes during sexual excitation. A laser Doppler was used to measure blood ow changes following clitoral and pelvic plexus nerve stimulations. Results show an increase in clitoral blood¯ow following clitoral nerve (df 1 12, df 2 108, F 21.4, P`0.001) and pelvic plexus nerve stimulations (n 3). A vaginal blood¯ow increase is also observed following pelvic plexus nerve stimulations (df 1 12, df 2 108, F 4.75, P`0.001). The female rat can therefore be used as a model for the study of the physiology, pharmacology and sexual dysfunction relating to blood¯ow in clitoral and vaginal tissue.
Participation of pelvic nerve branches in male rat copulatory behavior
Physiology & Behavior, 1994
Participation of pelvic nerve branches in male rat copulatory behavior. PHYSIOL BEHAV 55(2) 241-246, 1994.--The role of the pelvic nerve branches in the mediation of copulatory behavior was investigated. The somatomotor or the viscerocutaneous branch of the pelvic nerve was bilaterally sectioned in sexually experienced male rats. Somatomotor branch surgery had no detectable effect. Viscerocutaneous branch transection altered copulatory parameters that reflect impairments in penile erection and seminal plug emission. The altered behavioral parameters approached or reached presurgical and sham values 21 days after transection, indicating that the damage to erectile and ejaculatory function was transient. It is suggested that animals with viscerocutaneous branch transection recover copulatory etficiency through a compensatory plastic mechanism, possibly involving the hypogastric nerve.
Sacro-lumbar Intersegmental Spinal Reflex in Autonomic Pathways Mediating Female Sexual Function
The Journal of Sexual Medicine, 2011
Autonomic neurons in paracervical ganglia mediating vasodilation in the female reproductive tract receive inputs from both midlumbar and sacral spinal levels. However, it is not known how the lumbar pathways are activated. Aim. This study tested whether stimulation of pudendal sensory nerve could activate lumbar spinal outflows to paracervical ganglia via a spinal reflex pathway. Methods. Isolated spinal cords with attached peripheral nerves were removed from urethane-anesthetized female guinea pigs and perfused via the aorta with physiological salt solution. Spinal pathways to midlumbar preganglionic neurons were tested by recording extracellular compound action potentials (CAPs) in lumbar splanchnic or distal hypogastric nerves after electrical stimulation of thoracic spinal cord or the pudendal nerve. CAPs also were recorded from pelvic nerves after pudendal nerve stimulation. Sensory neurons were retrogradely traced from the pudendal nerve and characterized immunohistochemically. Main Outcome Measures. Activation of preganglionic neurons projecting from midlumbar spinal cord to paracervical ganglia following stimulation of pudendal sensory nerves in isolated preparations. Results. Thoracic spinal cord stimulation produced CAPs in hypogastric nerves that were abolished by transection of L3 lumbar splanchnic nerves. Pudendal nerve stimulation produced CAPs in L3 lumbar splanchnic, hypogastric, and pelvic nerves, demonstrating an ascending intersegmental spinal circuit to midlumbar levels in addition to the sacral spinal circuit. These CAPs in hypogastric nerves were enhanced by bicuculline (10 mM), blocked by tetrodotoxin (1 mM) but were not affected by hexamethonium (200 mM). Retrograde axonal tracing revealed four groups of sensory neurons in S3 dorsal root ganglia that were distinguished immunohistochemically. Conclusion. Midlumbar preganglionic neurons projecting to paracervical ganglia regulating blood flow and motility in the female reproductive tract can be activated by an ascending intersegmental spinal pathway from pudendal sacral inputs, which is inhibited by local spinal circuits. This pathway will help understand pathological conditions affecting reproductive function. Yuan SY, Gibbins IL, Zagorodnyuk VP, and Morris JL. Sacro-lumbar intersegmental spinal reflex in autonomic pathways mediating female sexual function. J Sex Med 2011;8:1931-1942.
The Anatomical Record, 1989
An understanding of the composition of the various nerves of the pelvic plexus is essential in the design of studies to explore the autonomic control of pelvic visceral tissues. As a correlate of this interest, the present study was designed to determine the composition of the main penile nerve in the pelvic plexus of the laboratory rat, an animal commonly used for studies of reproductive physiology. Retrograde tracing studies indicate that the main penile nerve contains neurons which project to the penile crura, the corpus spongiosum, and the bulbourethral glands. The main penile nerve is the major source of neurons which innervate the corpus spongiosum and bulbourethral gland and contains about one-third of all parasympathetic neurons which project to the penile crura. Dye placed on the proximal cut end of the main penile nerve indicates that neurons in the parasympathetic region of the spinal cord (L6-S1) and to a lesser extent a sympathetic region of the cord, L1-L2, provide preganglionic innervation to ganglion cells in the main pelvic nerve. Processes of neurons in dorsal root ganglia L6-S1 and of neurons in the abdominopelvic sympathetic chain course in the main penile nerve to unknown destinations. In many respects this presumed postganglionic fiber tract is essentially a region of the pelvic plexus which subserves extrapelvic visceral tissues.
Journal of Urology, 1993
An animal model using the spinal rat was characterized. Electrical stimulation of the dorsal nerve of the penis elicited reflex tonic erections of the penile body and reflex bulbospongiosus muscle activity, flips and ejaculations. The tonic erections of the penile body are independent from contractions of the bulbospongiosus muscle and appear to be the result of a neurovascular process. Our observations suggest that reflex bulbospongiosus muscle activity, flips and ejaculations are a single complex reflex response, which we define as reflex ejaculatory response. Two parameters predicted the occurrence and type of reflex response. The visualization of bulbospongiosus muscle activity during surgical isolation of the dorsal nerve of the penis was sufficient to anticipate the elicitability of reflex ejaculatory responses. The latter, together with a systemic systolic pressure 2: 73 mmHg., warranted the elicitability of reflex tonic erections. The similarities found in the physiology of rat tonic penile body erections and of human erections make this model promising for further elucidation of sexual function. Moreover, the present model may prove useful for the investigation of neurogenic erectile dysfunction, and of neurogenic ejaculatory disorders.