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The aims of the present study were to describe, in male rats, the anatomical organization of the major and accessory pelvic ganglia (MPG, AG; respectively), the interrelationship of the pelvic plexus components, and the morphometry of the pelvic postganglionic neurons. Anatomical, histochemical and histological studies were performed in anesthetized adult Wistar male rats. We found that the pelvic plexus consists of intricate neural circuits composed of two MPG, and three pairs of AG (AGI, AGII, AGIII) anatomically interrelated through ipsilateral and contralateral commissural nerves. Around 30 nerves emerge from each MPG and 17 from AGI and AGII. The MPG efferent nerves spread out preganglionic information to several pelvic organs controlling urinary, bowel, reproductive and sexual functions, while AG innervation is more regional, and it is confined to reproductive organs located in the rostral region of the urogenital tract. Both MPG and AG contain nerve fascicles, blood vessels, small intensely fluorescent cells, satellite cells and oval neuronal somata with one to three nucleoli. The soma area of AG neurons is larger than those of MPG neurons (p 0.005). The MPG contains about 75% of the total pelvic postganglionic neurons. Our findings corroborated previous reports about MPG inputs, and add new information regarding pelvic ganglia efferent branches, AG neurons (number and morphometry), and neural interrelationship between the pelvic plexus components. This information will be useful in designing future studies about the role of pelvic innervation in the physiology and pathophysiology of pelvic functions.

Prostate function is regulated by androgens and a neural control via the pelvic and hypogastric nerves. As such, this sexual gland contains receptors for acetylcholine and noradrenaline, although it is unknown whether the expression of these receptors is affected by sexual behavior and even less by denervation of the gland. Thus, the purpose of this work was to evaluate the effect of repeated sexual behavior on the expression of noradrenaline, acetylcholine, and androgen receptors at the prostate, and how they are affected by denervation. To achieve this, we used sexually experienced males denervated at the pelvic or hypogastric nerves, or both. The messenger (mRNA) and protein for androgen, noradrenergic, and cholinergic receptors were evaluated. The weight of the gland and the levels of serum testosterone were also measured. We found that: (1) sexual behavior was not affected by denervation; (2) blood testosterone levels increased due to sexual behavior but such increase is prevented by denervation; (3) the weight of the ventral prostate increased with sexual behavior but was not affected by denervation; (4) AR messenger levels increased with sexual behavior but were not altered by denervation; (5) the messenger for noradrenergic and cholinergic receptors decreased after denervation, and those for muscarinic receptors increased, and (6) only AR protein decreased after denervation of both nerves, while those for other receptors remained unchanged. In summary, we show that the three receptors have different regulatory mechanisms, and that only androgen receptors are regulated by both autonomic systems.

Iatrogenic injury to the spinal cord (SC) is not an uncommon complication of spinal surgery. In an attempt to establish a preventive therapy for anticipated SC injury, we tested the effect of a single dose (SD) vaccine vs. the addition of a booster dose (BD) of a neural-derived peptide (A91) prior to SC contusion. Immunization with A91 immediately after SC injury has demonstrated to induce significant tissue protection and motor recovery. After injury, only the BD vaccination schedule had a neuroprotective effect. It was capable of improving neurological recovery that was always significantly higher than the one observed in rats with SD immunization or those only treated with PBS. Toward the end of study, animals treated with an A91 BD presented a BBB score of 9.75 ± 0.17 (mean ± standard deviation) while rats treated with SD or PBS had a score of 6.6 ± 0.7 and 5.6 ± 0.6 respectively. In the next step we attempted to corroborate the neuroprotective effect induced by A91 immunization. For this purpose, we assessed the survival of rubrospinal neurons (RSNs) and ventral horn neurons (VHNs) sixty days after SC injury. BD vaccination induced a significant survival of both RSNs and VHNs after injury. Finally, the failure or success of this therapy (SD or BD respectively) was associated with a lower (SD) or higher (BD) A91-specific T cell proliferation. Prophylactic neuroprotection with an initial and subsequent booster dose of A91 may improve recovery after SC injury sustained during invasive spinal surgery procedures.

Surgical microscopy and electrophysiological techniques were used to describe in the adult male rat the peripheral distribution of the sensory branch of the pudendal nerve (SBPdn) and its sensory and somatomotor axonal components. Gross and histological features of the urethralis muscle were also determined. We propose to name the SBPdn branches according to the corresponding target structure. We found branches to the urethral diverticulum, major pelvic ganglion, corpus cavernosus of the penis, urethralis muscle, preputial glands, corpus spongiosus of the penis, foreskin and glans penis. Under the pubic bone three anastomotic branches form a bridge-like structure we called pelvic plexus. Through electrophysiological studies it was determined that the SBPdn carries efferent fibers to the striated urethralis muscle, as well as afferent axons from the glans penis and foreskin. We concluded that the SBPdn of the male rat has sensory and somatomotor components. This nerve is mixed and not exclusively sensory as was previously described. The finding of the anatomic relation to the major pelvic ganglion implies nerve communication with the autonomic nervous system. The functions of the somatomotor component and nerves to the urethral diverticulum, cavernosus bodies and preputial glands of the SBPdn remain to be determined. According to its targets, this innervation could contribute in the control of genitourinary functions such as voiding, erection, ejaculation and urinary marking.

The damage in ischemic stroke is caused by two events: (i) the ischemic phenomenon by itself; (ii) the self-destructive mechanisms developed as a consequence of ischemia. The inflammatory response is one of these destructive phenomena that accompanies and exacerbates the developing injury. Since it has been suggested that immune cells participate in neuroprotective and restorative processes, modulation rather than elimination of this inflammatory response could be a strategy to improve the neurological outcome. The immune modulator copolymer-1 (Cop-1), a synthetic basic random copolymer of amino acids, is a potent inducer of Th2 regulatory cells which, aside from exerting modulatory actions, is capable of releasing neurotrophic factors. There is evidence that Cop-1-specific T cells exert neuroprotective and even restorative effects in diverse neurodegenerative diseases. In order to test the ability of Cop-1 to prevent ischemic injury in a model of transient middle cerebral artery (MCA) occlusion, two groups of rats were treated either with Cop-1 or with saline solution (SS). Seven days after occlusion, Cop-1 treated rats presented a significant improvement in neurological function compared to SS-treated animals (1.2+/-0.4 and 2.8+/-0.5 mean+/-S.D., respectively; p=0.008). Histological findings showed that the percentage of infarct volume was smaller in Cop-1 treated rats (4.8+/-1.5), in comparison with those receiving SS (32.2+/-8.6; p=0.004). Cop-1 constitutes a promising therapy for stroke; thereby, the enforcement of further experimental investigation is encouraged in order to be able to formulate the best strategy.

Little information is available on the participation of the perineal striated muscles in female reproductive processes. Here, we describe the gross anatomy and innervation of two striated perineal muscles in the female rabbit, the bulbospongiosus (BSM) and ischiocavernosus (ISM), and analyze their reflex electromyographic (EMG) activity in response to stimulation of the perigenital skin and vaginal tract. Twenty-four mature chinchilla-breed rabbit does were used: 12 to describe the anatomy and innervation of the muscles, 9 to determine reflex EMG activity of the muscles in response to stimulation of the perigenital skin and specific levels of the vaginal tract and 3 to analyze the effect of contraction of the muscles on intravaginal pressure. Both muscles were well developed, with their fibers originating at the ischiadic arch and inserting onto the ligamentum suspensorium clitoridis. Branches of the clitoral and perineal nerves innervated the BSM and ISM, respectively. Bilateral electrical stimulation of these nerves provoked retraction of the clitoral sheath and an increase in intravaginal pressure at the level of the perineal vagina. Whereas neither muscle responded to stimulation of the perigenital skin, both were reflexively activated during mechanical stimulation of the inner walls of the perineal vagina. Prolonged cervical stimulation inhibited this reflex. Thus, in reproductive processes such as copulation and/or parturition, the contraction of these muscles may be induced during stimulation of the perineal vagina.

In the rat the pelvic nerve consists of a viscerocutaneous (sensory) branch which receives information from pelvic viscera and the midline perineal region, and a somatomotor (muscular) branch which innervates the ilio- and pubococcygeous muscles. To investigate the contribution of these branches to the parturition process, the length of gestation and course of delivery were closely monitored in 43 pregnant, Wistar-strain rats randomly assigned to five groups: untreated control animals, animals in which the somatomotor branch of the pelvic nerve was bilaterally sectioned on Day 14 of gestation, animals in which the viscerocutaneous branch of the pelvic nerve was bilaterally sectioned on Day 14 of gestation, animals treated similarly to the previous group but with young delivered by C-section at term, and sham-operated controls. Sectioning the viscerocutaneous branch seriously disrupted parturition and resulted in major dystocia and a high percentage of stillbirths in all females. In contrast, sectioning the somatomotor branch had no apparent effect on parturition and no significant differences were found between females of this group and sham or control dams on any of the measures recorded. It is concluded that the viscerocutaneous branch of the pelvic nerve is vital for the normal course of parturition in the rat but that the somatomotor branch plays little role, if any.

Responsiveness to pain was determined in female rats across the whole reproductive cycle using the tail-flick test. When tested immediately after mating, pain thresholds were unaltered, whereas 10 min later animals typically demonstrated hyperalgesia (Experiment 1). They also demonstrated hyperalgesia during most of pregnancy, and had significantly lower pain thresholds than the unmated controls except for the 24 h before parturition, when a sudden increase in tail-flick latencies was recorded (Experiment 2). Pain thresholds were also significantly lower throughout the nursing period but increased significantly when dams were separated from their litters for 6 h, and returned to premating baseline values within 24 h of weaning (Experiment 3). These findings confirm and extend earlier reports that female reproductive state may significantly modify responsiveness to noxious stimuli, and it is suggested that differences between the results of this and previous studies may be at least partly explained by the relatively stress-free test procedure adopted here.

Pain threshold was determined in female rats using the tail flick test. Latency to respond depended on the locus of the tail heated, with the most distal sites resulting in the shortest response times (Experiment 1). Tail flick latency also varied according to the time of day, with shorter response times recorded around the middle of the dark phase than near its beginning or after its end. This was the case for intact, for ovariectomized, and for ovariectomized, estradiol-treated rats (Experiment 2). However, response times also varied across the estrous cycle, with significantly shorter latencies recorded during estrus and metestrus. Ovariectomy abolished these fluctuations, and whereas administration of estradiol increased response times, progesterone had little effect (Experiment 3). These results suggest that site of tail heating, time of day, and presence of ovarian hormones can influence tail flick latency independently, thus demonstrating the complexity of the mechanisms that may contribute to pain threshold even within the same paradigm.

Objectives To determine whether the small plexus located at the base of the penis, consisting of nerves arising from the major pelvic ganglion, connecting with the sensory branch of the pudendal nerve, contains postganglionic neurons innervating the erectile tissue and urethra of the penis. Methods A total of 22 adult male Wistar rats 3-4 months of age (weight 250-350 g) were used. The features, distribution, and topography of the small plexus were determined by gross anatomy and histologic studies (Masson's trichrome and Nissl stain). Postganglionic neurons were traced with horseradish peroxidase-wheat germ agglutinin injected in the cavernosum, spongiosum corpora, and penile urethra. Results The small plexus located at the base of the penis has ganglia containing cells with large nuclei. The cells were stained with the Nissl technique confirming they are neurons. The neurons were positively labeled with horseradish peroxidase-wheat germ agglutinin after the tracer was injected in the penile structures. Conclusions In the male rat, the small plexus located at the base of the penis contains postganglionic neurons innervating the penile structures. These neurons can contribute to the regulation of the sexual and urinary function of the genitourinary tract. Because the rat is the main laboratory animal used in urologic studies, it is important to consider, when designing experiments or discussing results, that in addition to the major pelvic ganglion, other postganglionic neurons of the penis are provided by the small plexus. The small plexus could be named the minor pelvic ganglia and considered a component of the pelvic plexus.