Ablation of the inferior mesenteric plexus in the rat: alteration of sperm storage in the epididymis and vas deferens

In Vitro Contraction of Isolated Cauda Epididymal Duct Smooth Muscle as a Complimentary Approach to Physiological, Pathological, Toxicological, and Pharmacological Studies on Epididymal Function

Contraction of cauda epididymal duct (CE) smooth muscle is one of the very first events of the seminal emission phase of ejaculation. The contraction of CE smooth muscle is governed by a complex interaction of hormones, autacoids, and by the neurotransmitters released from the epididymal intramural nerve endings, and any impairment in the CE smooth muscle contraction has the potential to impair male fertility. Apart the obvious pathophysiological and toxicological importance of CE smooth muscle contraction, modulation of CE contraction has pharmaceutical interest offering a druggable target to development of drugs to improve/impair male fertility. The in vitro contraction experiments constitute a valuable approach to an in-depth evaluation of functional and molecular changes resulting from pathologies or drug exposure. Therefore, this chapter consists in a description of in vitro pharmacological reactivity contractility of the epididymal duct in a controlled medium, maintained at 30 °C of temperature and continuously bubbled with 95% O₂ and 5% CO₂ to obtain cumulative concentration-response curves that has been fundamental to some of our investigations on epididymal physiology, toxicology, and pharmacology.

Bupropion treatment increases epididymal contractility and impairs sperm quality with no effects on the epididymal sperm transit time of male rats

Bupropion is a dopamine (DA) and norepinephrine (NE) reuptake inhibitor used as smoking cessation and antidepressant drug with a lower incidence of male sexual dysfunction. We showed previously that sibutramine, a norepinephrine/serotonine reuptake inhibitor, reduced male rat fertility. As there are no studies evaluating the impact of bupropion treatment on spermatic parameters and male fertility, we evaluated the effects of bupropion treatment (15 and 30 mg kg(-1), 30 days) on sexual behavior, spermatic parameters and fertility of male Wistar rats and on the epididymal duct in vitro contractility. Bupropion 15 mg kg(-1) increased the serum luteinizing hormone level and the epididymal duct contractility, but the sperm quality was not affected. At 30 mg kg(-1) bupropion impaired sperm quality increasing the incidence of non-progressive sperm. The male sexual behavior and fertility were not modified at both bupropion doses. These results, in rats, suggest the importance of studies evaluating the effects of bupropion on the human male sperm quality.

Disruption of estrogen receptor signaling and similar pathways in the efferent ductules and initial segment of the epididymis

Seminiferous tubular atrophy may involve indirectly the disruption of estrogen receptor-α (ESR1) function in efferent ductules of the testis. ESR1 helps to maintain fluid resorption by the ductal epithelium and the inhibition or stimulation of this activity in rodent species will lead to fluid accumulation in the lumen. If not resolved, the abnormal buildup of fluid in the head of the epididymis and efferent ductules becomes a serious problem for the testis, as it leads to an increase in testis weight, tubular dilation and seminiferous epithelial degeneration, as well as testicular atrophy. The same sequence of pathogenesis occurs if the efferent ductule lumen becomes occluded. This review provides an introduction to the role of estrogen in the male reproductive tract but focuses on the various overlapping mechanisms that could induce efferent ductule dysfunction and fluid backpressure histopathology. Although efferent ductules are difficult to find, their inclusion in routine histological evaluations is recommended, as morphological images of these delicate tubules may be essential for understanding the mechanism of testicular injury, especially if dilations are observed in the rete testis and/or seminiferous tubules.

Signature Lesion:

The rete testis and efferent ductules can appear dilated, as if the lumens were greatly expanded with excess fluid or the accumulation of sperm. Because the efferent ductules resorb most of the fluid arriving from the rete testis lumen, one of two mechanisms is likely to be involved: a) reduced fluid uptake, which has been caused by the disruption in estrogen receptor signaling or associated pathways; or b) an increased rate of fluid resorption, which results in luminal occlusion. Both mechanisms can lead to a temporary increase in testicular weight, tubular dilation and atrophy of the seminiferous tubules.

Presence and function of dopamine transporter (DAT) in stallion sperm: dopamine modulates sperm motility and acrosomal integrity

Dopamine is a catecholamine with multiple physiological functions, playing a key role in nervous system; however its participation in reproductive processes and sperm physiology is controversial. High dopamine concentrations have been reported in different portions of the feminine and masculine reproductive tract, although the role fulfilled by this catecholamine in reproductive physiology is as yet unknown. We have previously shown that dopamine type 2 receptor is functional in boar sperm, suggesting that dopamine acts as a physiological modulator of sperm viability, capacitation and motility. In the present study, using immunodetection methods, we revealed the presence of several proteins important for the dopamine uptake and signalling in mammalian sperm, specifically monoamine transporters as dopamine (DAT), serotonin (SERT) and norepinephrine (NET) transporters in equine sperm. We also demonstrated for the first time in equine sperm a functional dopamine transporter using 4-[4-(Dimethylamino)styryl]-N-methylpyridinium iodide (ASP⁺), as substrate. In addition, we also showed that dopamine (1 mM) treatment in vitro, does not affect sperm viability but decreases total and progressive sperm motility. This effect is reversed by blocking the dopamine transporter with the selective inhibitor vanoxerine (GBR12909) and non-selective inhibitors of dopamine reuptake such as nomifensine and bupropion. The effect of dopamine in sperm physiology was evaluated and we demonstrated that acrosome integrity and thyrosine phosphorylation in equine sperm is significantly reduced at high concentrations of this catecholamine. In summary, our results revealed the presence of monoamine transporter DAT, NET and SERT in equine sperm, and that the dopamine uptake by DAT can regulate sperm function, specifically acrosomal integrity and sperm motility.

Effects of traction on the spermatic cord of rats

PURPOSE

To determine whether tension in the spermatic cord of rats causes lesions in the testis, epididymis or vas deferens.

METHODS

Forty Wistar rats were randomly allocated into four groups. A traction force of 1.6 Newton (N) in group I and 1 N in group II was applied to the right spermatic cord. Group III was the sham, and group IV served as the control.

RESULTS

Testicular lesions occurred on the right side in 66.7% of the rats and on the left side in 46.1% of the rats. The testes showed a decreased number of Sertoli cells, necrosis and a decreased number of germ cells in the seminiferous tubules. Anatomopathological changes in the vas deferens were not identified. There was no decrease in the thickness of the muscle wall of the vas deferens. In the right epididymis, 71.8% of the animals showed a reduction and 5% showed an absence of intraluminal sperm. In the left epididymis, 37.5% of the rats showed a reduction. The volume and the final testicular weight of the right side in group IV was different from those in the other groups.

CONCLUSIONS

Anatomopathological lesions were found in the testis and epididymis.

Slimmer or fertile? Pharmacological mechanisms involved in reduced sperm quality and fertility in rats exposed to the anorexigen sibutramine

Sperm acquire motility and fertility capacity during epididymal transit, under the control of androgens and sympathetic innervations. It is already known that the acceleration of epididymal sperm transit time can lead to lower sperm quality. In a previous work we showed that rats exposed to the anorexigen sibutramine, a non-selective serotonin-norepinephrine reuptake inhibitor, presented faster sperm transit time, lower epididymal sperm reserves and potentiation of the tension of epididymal duct to norepinephrine exposed acutely in vitro to sibutramine. In the present work we aimed to further investigate pharmacological mechanisms involved in these alterations and the impact on rat sperm quality. For this, adult male Wistar rats were treated with sibutramine (10 mg/kg/day) or vehicle for 30 days. Sibutramine decreased final body, seminal vesicle, ventral prostate and epididymal weights, as well as sperm transit time in the epididymal cauda. On the contrary of the in vitro pharmacological assays, in which sibutramine was added directly to the bath containing strips of distal epididymal cauda, the ductal tension was not altered after in vivo sub-chronic exposure to sibutramine. However, there is pharmacological evidence that the endogenous epididymal norepinephrine reserves were reduced in these animals. It was also shown that the decrease in prostate weight can be related to increased tension developed of the gland, due to sibutramine sympathomimetic effects. In addition, our results showed reduced sperm quality after in utero artificial insemination, a more sensitive procedure to assess fertility in rodents. The epididymal norepinephrine depletion exerted by sibutramine, associated with decreases in sperm transit time, quantity and quality, leading to reduced fertility in this experimental model, reinforces the concerns about the possible impact on fertility of man taking sibutramine as well as other non-selective serotonin-norepinephrine reuptake inhibitors, especially considering the lower reproductive efficiency of humans compared to males of other species.

Immunolocalization of alpha(1A)-adrenoceptors in rat and human epididymis

Immunohistochemistry was conducted to analyze the cellular localization of alpha(1A)-adrenoceptors along rat and human epididymis. ADR-A, a polyclonal antibody that recognizes the specific C-terminal region of alpha(1A)-adrenoceptors, immunostained this adrenoceptor subtype in smooth muscle cells surrounding the epididymal tubules and interstitial blood vessels and in subpopulations of epithelial cells from adult rat and human caput and cauda epididymidis. The same cell types from rat epididymidis were immunostained by ADR-1, a polyclonal antibody that recognizes a common region of the three alpha(1)-adrenoceptor subtypes, alpha(1A), alpha(1B), and alpha(1D). Immunostaining with both antibodies was also conducted in adult rat and human vas deferens and seminal vesicle used as positive controls because of the abundance of alpha(1A)-adrenoceptors in these tissues. ADR-A- and ADR-1-positive immunostaining was differentially distributed depending on the antibody, method of tissue fixation (Bouin-fixed and fresh frozen tissues), species (rat and human), tissue (caput and cauda epididymidis), and age (immature and adult rats) analyzed. This is the first report immunolocalizing alpha(1A)-adrenoceptor along rat and human epididymis. The presence of this adrenoceptor subtype in epididymal smooth muscle and epithelial cells indicates their contribution to smooth muscle contractile responses and a possible role in the absorptive and/or secretory activities of the epithelium lining the epididymal duct. Taken together, our results should contribute to a better understanding of the physiological role of alpha(1)-adrenoceptors in the epididymidis and the importance of the sympathetic nervous system for male (in)fertility.

Effects of spinal cord injury on semen parameters

OBJECTIVE/BACKGROUND

Neurogenic reproductive dysfunction in men with spinal cord injury (SCI) is common and the result of a combination of impotence, ejaculatory failure, and abnormal semen characteristics. It is well established that the semen quality of men with SCI is poor and that changes are seen as early as 2 weeks after injury. The distinguishing characters of poor quality are abnormal sperm motility and viability. In the majority of the men with SCI, the sperm count is not abnormal. We elaborate on the effects of the SCI on semen parameters that may contribute to poor motility and poor viability.

METHODS

Review.

DESIGN

PubMed and MEDLINE databases were searched using the following key words: spinal cord injuries, fertility, sexual dysfunction, and spermatogenesis. All literature was reviewed by the team of authors according to the various stages of sperm development and transport in the male reproductive cycle.

FINDINGS

The cause of asthenozoospermia appears to be multifactorial.

CONCLUSION

Current literature does not support the preeminence of a single factor relating to neurogenic reproductive dysfunction in men with SCI. After SCI, there is ample evidence of disturbance of sperm production, maturation and storage, and transport due to an abnormal neuroendocrine milieu. Semen quality seems to be primarily affected by changes to the seminal plasma constituents, type of bladder management, and the neurogenic impairment to the ejaculatory function. Further focused and structured studies are required.

Differential modulation of bovine epididymal activity by oxytocin and noradrenaline

Passage of spermatozoa through the epididymis and emission of sperm during ejaculation are based on spontaneous and induced contractions of epididymal peritubular muscle layers. This study deals with the ejaculation-relevant factors noradrenaline (NA) and oxytocin (OT) and their contractile effects in the course of the bovine epididymal duct. Muscle tension recording revealed excitatory effects of NA in all duct regions. A peculiarity was found in a duct section between the mid-cauda and ductus deferens, where the responsiveness to NA was particularly faint in comparison with the adjacent regions. NA-induced contraction was primarily mediated by postjunctional alpha(2)-adrenoceptors (ADRA) in the caput and corpus regions, and by alpha(1)-ADRA in the cauda region. Contrary to NA, OT exerted regionally varying effects. The peptide induced contraction in intact and epithelium-denuded caput as well as in epithelium-denuded corpus segments but had a relaxant net effect in intact corpus and proximal cauda segments. Within the mid-cauda, OT evoked strong contraction, which progressively decreased distally. Receptor specificity of the epididymal OT effects was verified using the selective OT receptor (OTR) agonist [Thr(4),Gly(7)]OT and vasopressin. OTR immunoreactivity was detected in the epididymal peritubular muscle wall and epithelial principal cells. RT-PCR analysis confirmed the presence of OTR in all duct regions. In summary, different contractile responses to OT and NA occur in the course of the epididymal duct, possibly preventing excessive sperm transport through the corpus and serving orthograde emission of sperm during ejaculation.

Effects of altered epididymal sperm transit time on sperm quality

The epididymal sperm transit time seems to have an important role in the process of sperm maturation, and it seems that alterations to the transit can harm the process. The aim of the present work was to evaluate the influence of altered sperm transit time through the epididymis on sperm parameters and fertility of rats, as well as the role of testosterone in the alterations. Sprague-Dawley adult male rats were randomly assigned to four different groups and were treated for 12 days: (i) 10 microg/rat/day DES, to accelerate the transit; (ii) 6.25 mg/kg/day guanethidine sulphate, to delay the transit; (iii) same treatment as group 1, plus androgen supplementation; (iv) control animals received the vehicles. Guanethidine treatment delayed the sperm transit time through the epididymal cauda, provoking increased sperm reserves in this region. Animals exposed to DES showed an acceleration of sperm transit time in the epididymis, and consequently decreased sperm density in both epididymal regions, the caput-corpus and cauda, and diminished sperm motility. In both cases sperm production was not altered. Testosterone supplementation was able to restore the transit time to values close to normality, as they were higher than in the control rats. The same occurred in relation to sperm motility. Rats exposed to DES presented lower fertility after in utero artificial insemination using sperm collected from the proximal cauda epididymis. Therefore, it was concluded that the acceleration of rat sperm transit time appeared to harm normal sperm maturation, thus decreasing sperm quality and fertility capacity, in an androgen-dependent way.

Expression and localization of muscarinic acetylcholine receptor subtypes in rat efferent ductules and epididymis

The expression of muscarinic acetylcholine receptor (mAChR) subtypes (M(1)-M(5)) was studied in the rat efferent ductules and epididymis at the mRNA and protein levels. The relative abundance of each mAChR transcript subtype differed depending on the tissue and the epididymal region analyzed. The M(1) mAChR mRNA level was more abundant in the efferent ductules than in the caput and cauda of the epididymis. The M(2) mAChR mRNA level was similar between the efferent ductules and caput of the epididymis and higher in the cauda region. The M(3) mAChR mRNA level was low in the efferent ductules and caput of the epididymis, but high levels were detected in the cauda region. mRNAs for M(4) and M(5) mAChRs were not detected in these tissues. Our studies indicated a variable degree of immunostaining for each mAChR subtype in a cell-type and tissue-specific pattern. M(1) mAChR was detected over the efferent ductule epithelium. M(2) and M(3) mAChRs were observed in the apical region of the ciliated cells. Apical and narrow cells of the initial segment showed distinct staining by M(1) antibody, whereas a supranuclear reaction was noted in the principal cells of the caput of the epididymis. In addition, staining for M(1) and M(2) mAChRs was visible in the apical membrane of some epithelial cells of the cauda region. M(3) mAChR was detected in the peritubular smooth muscle of the efferent ductules and epididymis. Functional studies suggested the involvement of this subtype in epididymal tubule contraction. Thus, the cell-specific expression of the various mAChR subtypes in the efferent ductules and epididymis suggests that these receptors play a role in the modulation of luminal fluid composition and smooth muscle contraction.

Effects of testosterone on muscarinic acetylcholine receptors in the rat epididymis

The effect of testosterone on the expression of muscarinic acetylcholine receptor (mAChR) subtypes was studied in the rat epididymis, at mRNA and protein level. The rat androgen status was monitored by measuring plasma testosterone level and caput and cauda epididymis wet weight. Ribonuclease protection assay (RPA) and [3H]quinuclidinyl benzilate ([3H]QNB) binding assay were performed in the caput and cauda epididymis from control (50-day old), castrated, castrated and treated with testosterone and sexually immature (30-day old) rats. The expression of each mAChR transcript subtype differed depending on the epididymal region analyzed and rat testosterone and/or testicular factors status. In control rats, RPA showed the presence of mRNA for M1, M2 and M3 mAChR in the caput and cauda epididymis. The abundance of m2 and m3 transcripts in the cauda was higher than that in the caput epididymis. Low amount of m1 transcript was observed in both regions. Orchidectomy increased m1 mRNA amount in the caput and cauda epididymis when compared to control rats, an effect slightly modified by testosterone replacement. Although orchidectomy down-regulated the level of m2 transcript in both epididymal regions, castration significantly increased m3 mRNA amount in the caput region. These effects on m2 and m3 transcripts were prevented by testosterone replacement to castrated rats. Similar abundance of m3 transcript, however, was detected in the cauda epididymis of all experimental group tested. [3H]QNB binding studies revealed that orchidectomy down-regulated the number of mAChR detected in both epididymal regions, an effect also prevented by testosterone replacement. Thus, testosterone and/or testicular factors may play a role in the regulation of mAChR expression in the rat epididymis.

Supraspinal connections of the reproductive organs: structural and functional aspects

Gonadal functions are governed by the hypothalamo-hypophyseal system. Other organs of the reproduction tract are under the regulatory action of gonadal steroids. In the past two decades several data have been accumulated on the involvement of fine-tuning control mechanisms which include autocrine and paracrine effects of biologically active substances produced locally and the regulatory action of nerves innervating the organs of the system. Recent studies using the viral transsynaptic technique have revealed cell groups in the central nervous system that are transneuronally connected with the male and female reproductive organs. This review summarizes neuromorphological data on the supraspinal innervation of reproductive organs and the functional significance of these brain areas in the control of reproduction.

Spermatogenesis and sperm transit through the epididymis in mammals with emphasis on pigs

Starting from the period of testis differentiation, the Sertoli cell plays a pivotal role in the development of a functional testis. FSH is the major mitotic factor for Sertoli cells. Because the supporting capacity of Sertoli cells is relatively fixed for each species, their total number per testis, established just before puberty (approximately 4 months in pigs), dictates the potential for sperm production. In contrast to Sertoli cells that are still undifferentiated, mature Leydig cells are already present at birth in pigs. Spermatogenesis lasts from 30 to 75 days in mammals, and this time period is under the control of the germ cell genotype. In boars, each spermatogenic cycle and the entire spermatogenic process lasts 8.6-9.0 and approximately 40 days, respectively. The sperm transit through the epididymis takes approximately 10 days in pigs and this is within the range cited for most mammals. Germ cell loss occurs normally during spermatogenesis, mainly during the spermatogonial and meiotic phases. In pigs, significant germ cell loss also takes place during spermiogenesis. In mammals in general, including pigs, only 2-3 out of a possible 10 spermatozoa are produced from each differentiated type A1 spermatogonium. The high supporting capacity of Sertoli cells and the short duration of the spermatogenic cycle are the main factors responsible for the comparatively high spermatogenic efficiency of pigs.

Penile vibratory stimulation and electroejaculation in the treatment of ejaculatory dysfunction

The purpose of this review is to present the current understanding of penile vibratory stimulation (PVS) and electroejaculation (EEJ) procedures and its clinical use in men with ejaculatory dysfunction. Unfortunately, the record of treating such individuals has been quite poor, but within recent years development and refinement of PVS and EEJ in men with spinal cord injury (SCI) has significantly enhanced the prospects for treatment of ejaculatory dysfunction. The majority of spinal cord injured men are not able to produce antegrade ejaculation by masturbation or sexual stimulation. However, approximately 80% of all spinal cord injured men with an intact ejaculatory reflex arc (above T10) can obtain antegrade ejaculation with PVS. Electroejaculation may be successful in obtaining ejaculate from men with all types of SCI, including men who do not have major components of the ejaculatory reflex arc. Because vibratory stimulation is very simple in use, non-invasive, it does not require anaesthesia and is preferred by the patients when compared with EEJ, PVS is recommended to be the first choice of treatment in spinal cord injured men. Furthermore, EEJ has been successfully used to induce ejaculation in men with multiple sclerosis and diabetic neuropathy. Any other conditions which affect the ejaculatory mechanism of the central and/or peripheral nervous system including surgical nerve injury may be treated successfully with EEJ. Finally, for sperm retrieval and sperm cryopreservation before intensive anticancer therapy in pubertal boys, PVS and EEJ have been successfully performed in patients who failed to obtain ejaculation by masturbation. Nearly all data concerning semen characteristics in men with ejaculatory dysfuntion originate from spinal cord injured men. Semen analyses demonstrate low sperm motility rates in the majority of spinal cord injured men. The data give evidence of a decline in spermatogenesis and motility of ejaculated spermatozoa shortly after (few weeks) an acute SCI. Furthermore, it is suggested that some factors in the seminal plasma and/or disordered storage of spermatozoa in the seminal vesicles are mainly responsible for the impaired semen profiles in men with chronic SCI. Home insemination with semen obtained by penile vibratory and introduced intravaginally in order to achieve successful pregnancies may be an option for some spinal cord injured men and their partners. The majority of men will further enhance their fertility potential when using either penile vibratory or EEJ combined with assisted reproduction techniques such as intrauterine insemination or in-vitro fertilization with or without intracytoplasmic sperm injection.

On the intrinsic innervation of the epididymis of the camel (Camelus dromedarius)

The innervation of the camel epididymis was studied in 26 apparently healthy, sexually mature animals aged between 4 and 12 years. The material was collected during the different seasons of the year. Generally, five samples were taken from each epididymis. To demonstrate the general innervation pattern, immunohistochemical reactions to protein gene product-9.5, neurofilaments and neuron-specific enolase were used, in addition to acetylcholinesterase histochemistry. The nerve supply of the epididymis comes from two sources: (1) The majority of fibers come from the N. spermaticus inferior and accompany the deferent duct. (2) Another contribution stems from the N. spermaticus superior and enters the head region of the epididymis. From the exterior, the nerves penetrate the capsule of the organ to reach the interductular connective tissue. The terminal ramifications are observed directly within the wall of the duct and the wall of the epididymal arteries. The veins of the camel epididymis are not innervated. In the wall of the ductus epididymidis, the nerve fibers form plexuses at the subepithelial level and in the muscular coat. The amount of nerve fibers increases from the head to the tail, paralleling an increase in the intrinsic musculature. The intramural and interductular innervation of epididymal body and tail shows clear seasonal variations: More fibers and stronger reactions are observed during the winter season; the lowest density and the weakest reactions occur during the summer season. All epididymal nerves of the camel are unmyelinated. The majority of the intramural fibers and all in the arterial wall represent postjunctional sympathetic axons, but in the intramural plexuses of the duct a considerable number of cholinergic fibers are also present. Neuropeptide Y is the most frequent peptidergic transmitter and generally co-localized with dopamine-beta-hydroxylase in the sympathetic axons. Vasoactive intestinal polypeptide has a distribution similar to that of the cholinergic fibers. Calcitonin gene-related peptide-positive axons occur in moderate numbers, but never in the arterial innervation. Together with the relatively rare substance P-containing fibers, the calcitonin gene-related peptide-positive axons seem to represent the only sensory nerves in the camel epididymis.

Alpha1-adrenoceptor subtypes in rat epididymis and the effects of sexual maturation

We have characterized the expression of alpha1-adrenoceptor in epididymis from rats in different stages of sexual maturation: 40 (immature), 60 (young adult), and 120 (adult) days of age. Plasma testosterone levels were low in the immature animals but increased significantly in the 60- and 120-day-old animals. These changes were followed by a progressive increase in rat body weight and in caput and cauda epididymis relative weight. Reverse transcription polymerase chain reaction assay indicated that alpha1a-, alpha1b-, and alpha1d-adrenoceptor transcripts were present in both caput and cauda epididymis from adult rats. Ribonuclease protection assays further indicated that the expression of these alpha1-adrenoceptor transcripts differed with age and epididymal region analyzed. Prazosin (nonselective alpha1 antagonist), 5-methyl urapidil (alpha1A-selective), and BMY 7378 (alpha1D-selective) displaced [3H]prazosin binding curves in caput and cauda epididymis from 40- and 120-day-old rats. The potency order for these antagonists, as calculated from the negative logarithm of the inhibition constant (pK(i)) values for the high-affinity sites, indicated a predominant population of alpha1A-adrenoceptor subtype in caput and cauda epididymis from adult animals. Differences in pK(i) values in caput and cauda epididymis from immature and adult animals also suggested that the relative amount of alpha1-adrenoceptors, at the protein level, is modulated by sexual maturation. Taken together, the changes in alpha1-adrenoceptor expression during sexual maturation may suggest specific roles for these receptors in epididymal function.

Characterization of muscarinic acetylcholine receptors in the rat epididymis

The aim of the present study was to characterize the muscarinic acetylcholine receptor subtypes present in the caput and cauda of rat epididymis. The specific binding of [3H]quinuclidinyl benzilate ([3H]QNB) to epididymal membranes was time dependent, temperature dependent, and saturable. The cauda epididymis showed higher affinity to [3H]QNB and higher muscarinic receptor density when compared to the caput region. The [3H]QNB binding was tested in competition studies with different muscarinic receptor antagonists. Each antagonist tested displaced [3H]QNB bound to caput and cauda epididymal membrane with similar affinity. Correlation among the negative logarithm of inhibition constant values (pK(i)) for these antagonists obtained in the epididymis with their correspondent published pK(i) values obtained in tissues that expressed each receptor subtype (M1, M2, M3, and M4) indicated that the muscarinic receptors present in caput and cauda epididymis belong to the muscarinic M2 receptor subtype. When reverse transcription-polymerase chain reaction was used to identify muscarinic receptor mRNA subtypes in the epididymis, only m2 transcripts were detected in the caput region, while both m2 and m3 mRNA subtypes were observed in the cauda region. In conclusion, these results demonstrate that muscarinic receptors are present in the rat epididymis, with expression levels dependent on the region of the epididymis analyzed. Thus, the cholinergic neurotransmitter in the epididymis may be a factor controlling contractility and/or the luminal fluid microenvironment.

Identification of CNS neurons involved in the innervation of the epididymis: a viral transneuronal tracing study

Cell groups of the spinal cord and the brain transsynaptically connected with the epididymis (caput, cauda) were identified by means of the viral transneuronal tracing technique. Pseudorabies virus was injected into the caput or the cauda epididymidis, and after survival times 4 and 5 days, the spinal cord and brain were processed immunocytochemically. Virus-labeled neurons could be detected in the preganglionic sympathetic neurons (lower thoracic and upper lumbar segments) and following virus injection into the cauda epididymidis, also in the sacral parasympathetic nucleus (L6-S1). Virus-infected perikarya were present in several brain stem nuclei (lateral reticular nucleus, gigantocellular and paragigantocellular nucleus, A5 noradrenergic cell group, caudal raphe nuclei, locus coeruleus, Barrington's nucleus, nucleus of the solitary tract, periaqueductal gray) and in the diencephalon (hypothalamic paraventricular nucleus, lateral hypothalamus). At the longer survival time, some telencephalic structures also exhibited virus-labeled neurons. The distribution of infected neurons in the brain was similar after virus injection into the caput or cauda epididymidis; however, earlier onset of infection was observed after inoculation into the cauda. The present findings provide the first morphological data on a multisynaptic circuit of neurons innervating the epididymis and presumably involved in the control of epididymal functions. reserved.

Canine model of infertility after spinal cord injury: time course of acute changes in semen quality and spermatogenesis

PURPOSE

We established a canine model of subfertility after spinal cord injury and examined the time course of acute changes in semen quality and spermatogenesis after spinal cord injury.

MATERIALS AND METHODS

Seven dogs underwent surgical T7 spinal cord injury. Six dogs were used as controls. Electroejaculation and testicular fine needle aspiration were performed at baseline and twice weekly for 3 weeks after spinal cord injury. Semen quality change was examined by standard semen analysis. Spermatogenesis was assessed by flow cytometry of testicular fine needle aspiration in all dogs as well as by testicular histology at study conclusion in 4 controls and 4 spinal cord injured dogs.

RESULTS

No significant changes in spinal cord injured dogs were noted before 3 weeks after injury. From baseline to 3 weeks after injury certain changes were evident in spinal cord injured dogs. Mean antegrade sperm motility decreased from 62.9% to 20.1% (p = 0.008), mean total sperm (antegrade plus retrograde total sperm) decreased from 423 to 294 x 106 which was not statistically significant, and the incidence of testicular haploid cells decreased from 75.6% to 48.3% (p = 0.028). No significant change in any parameter was present in control dogs. The mean number of mature spermatids per cross-sectional tubule on final testicular histology was significantly decreased in spinal cord injured dogs compared with controls (13.6 versus 43.9, p = 0.02).

CONCLUSIONS

In the canine model tested the dogs readily survived spinal cord injury, electroejaculation was effective for obtaining ejaculate and fine needle aspiration allowed serial examination of spermatogenesis. Three weeks after spinal cord injury but not before 3 weeks sperm motility and spermatogenesis were significantly decreased. However, at the same point this decrease in spermatogenesis was not yet reflected in the total ejaculated sperm count.

Sexual function in spinal cord lesioned men

STUDY DESIGN

Review of literature.

OBJECTIVE

To review the physical aspects related to penile erection, ejaculatory dysfunction, semen characteristics, and techniques for enhancement of fertility in spinal cord lesioned (SCL) men.

SETTING

Worldwide: individuals with traumatic as well as non-traumatic SCL.

RESULTS

Recommendations for management of erectile dysfunction in SCL men: If it is possible to obtain a satisfactory erection but of insufficient duration, then try to use a venous constrictor band to find out if this is sufficient to maintain the erection. Otherwise we recommend Sildenafil. If Sildenafil is not satisfactory then use intracavernous injection with prostaglandin E(1) (some SCL men may prefer cutaneous or intraurethral application). We discourage the implantation of penile prosthesis for the sole purpose of erection. Recommendations for management of ejaculatory dysfunction in SCL men: Penile vibratory stimulation (PVS) to induce ejaculation is recommended as first treatment choice. If PVS fails, SCL men should be referred for electroejaculation (EEJ). Semen characteristics: Impaired semen profiles with low motility rates are seen in the majority of SCL men. Recently reported data gives evidence of a decline in spermatogenesis and motility of ejaculated spermatozoa shortly after (few weeks) an acute SCL. It is suggested that some factors in the seminal plasma and/or disordered storage of spermatozoa in the seminal vesicles are mainly responsible for the impaired semen profiles in men with chronic SCL. Fertility: Home insemination with semen obtained by PVS and introduced intravaginally in order to achieve successful pregnancies may be an option for some SCL men and their partners. The majority of SCL men will further enhance their fertility potential when using either PVS or EEJ combined with assisted reproduction techniques such as intrauterine insemination or in vitro fertilization with or without intracytoplasmic sperm injection.

Fertility ratio in male rats: effects after denervation of two pelvic floor muscles

Fertility ratio is defined here as the proportion of females that a male can impregnate after a constant period of in-polygyny living. This ratio was investigated in male rats after denervation of two pelvic floor muscles, the pubococcygeus and iliococcygeus. Denervation was carried out by transecting the somatomotor branch of the pelvic nerve. The lesion did not modify the sexual behavior of males or their overall fertility, but decreased the weight of the ejaculated seminal plug. Consequently, the number of days living in cohabitation to induce pregnancy was increased in lesioned males (approximately 13 days) compared with intact and sham animals (approximately 5 days). These results showed that the fertility ratio was optimal when intact/sham males cohabited with females for two consecutive estrous cycles, but that lesioned males needed up to four cycles to induce most pregnancies. Two hypotheses are raised by our results. The first is that pelvic floor denervation decreases the forceful tension required to expel the semen from the prostatic urethra to the vagina, then an incomplete seminal plug is expelled. The second is that denervation cut afferent fibers that reflexively promote the continence of the semen deposited in the prostatic urethra during seminal emission, allowing some to leak out before ejaculation. The latter hypothesis can also explain the recovery of the fertility ratio in lesioned males. It could be a compensatory mechanism mediated by the pudendal nerve supply to the coccygeus muscle, the other pelvic floor muscle.

Seminal vesicle aspiration in spinal cord injured men: insight into poor sperm quality

PURPOSE

In men with spinal cord injury poor quality semen is seen when performing electroejaculation and penile vibratory stimulation. We determined whether sperm stasis within the seminal vesicles is a potential cause of this problem.

MATERIALS AND METHODS

Seminal vesicle aspiration was performed immediately before electroejaculation or penile vibratory stimulation in men with aspermia secondary to spinal cord injury. Sperm count and quality of seminal vesicle aspiration and subsequent ejaculation were compared with historical ejaculated counts, ultrasound findings and patient characteristics.

RESULTS

Mean total number of right plus left seminal vesicle sperm plus or minus standard deviation was 511 +/- 960 x 10(6). Mean total number of sperm obtained by seminal vesicle plus electroejaculation or penile vibratory stimulation was 918 +/- 1,261 x 10(6). Average motility and viability of the seminal vesicle aspirated sperm were 1.3 and 3.2%, respectively. Average motility of the ejaculated sperm was 26.4% after seminal vesicle aspiration versus 16.3% in previous ejaculation induction procedures performed in the same patients. Seminal vesicle aspirated sperm represented 66% of the total number of sperm obtained during the session and was equal to 49% of the sperm obtained at previous electroejaculation or penile vibratory stimulation sessions. The period of abstinence correlated only with ejaculate count (simple regression p = 0.009). No other clinical characteristics had any effect on sperm count or quality.

CONCLUSIONS

Large numbers of poor quality sperm are present within the seminal vesicles of spinal cord injured men and these sperm comprise a large portion of the specimens collected by electroejaculation or penile vibratory stimulation. This phenomenon is independent of the period of abstinence, implicating disordered storage of sperm due to spinal cord injury rather than infrequent ejaculation. The large number of senescent sperm within the seminal vesicles appears to be a primary cause of poor sperm quality in spinal cord injured men.

Rat epididymal sperm quantity, quality, and transit time after guanethidine-induced sympathectomy

Guanethidine, a chemical that selectively abolishes peripheral noradrenergic nerves, was used to investigate the role of sympathetic innervation in the maintenance of epididymal sperm quantity and quality. Four groups of 10 adult male rats each were treated daily for 21 days, by i.p. injections, with either 0 (saline vehicle), 6.25, 12.5, or 25 mg/kg guanethidine. Norepinephrine content was reduced to undetectable levels in the cauda epididymidis in all guanethidine groups after 3 wk of treatment and was reduced to 7.4% of the control values after 1 wk of 6.25 mg/kg treatment. While body weight gain was significantly decreased at 12.5 and 25 mg/kg compared to that in controls, there was a significant increase in the weights of the seminal vesicles/coagulating glands in all treated groups. The number of homogenization-resistant spermatids per testis and the daily sperm production per testis remained unchanged. The weight of the epididymis was significantly increased at 6.25 and 12.5 mg/kg. Moreover, the number of cauda epididymal sperm and the transit time were increased significantly at 6.25 mg/kg (10.2 days) compared to values in the control cauda (6.3 days). Neither serum testosterone levels nor LH was affected in a dosage-related manner. There were no effects of guanethidine treatment on cauda epididymal sperm motility or morphology. A quantitative analysis of detergent-extracted cauda epididymal sperm proteins by SDS-PAGE revealed no differences, but there were diminutions in seven proteins in homogenates of caput/corpus tissue. Histologic analysis of testis and epididymis sections revealed no differences between control and denervated animals. In a subsequent experiment the lowest effective dosage (6.25 mg/kg) was given to rats for 1 wk, and an increased number of cauda epididymal sperm and a delay in sperm transit were observed. Our results indicate that low-dosage guanethidine exposure denervates the epididymis within 1 wk, thereby delaying epididymal transit; however, neither 1- nor 3-wk exposure produces qualitative changes in the sperm.

Endothelin-1 is synthesized and biologically active in human epididymis via a paracrine mode of action

In a previous study, we reported the presence of endothelin-1 and endothelin receptors in the human testis. We have now extended our investigations to the human epididymis. Since sperm appear to be immotile during their transit through the epididymis, it is conceivable that specific local factors promote smooth muscle contraction, enabling sperm transport. In this paper, we show that endothelin-1 mRNA and protein are readily detectable in the epithelial compartment of the human epididymis, and that endothelin converting enzyme- 1, which converts the precursor pro-endothelin-1 into active endothelin-1, is expressed in the epididymis, consistent with active processing of the prohormone. In addition, two classes of endothelin receptors were characterized and located in the muscle cells of the epididymis. These receptors correspond, in terms of affinity constants and capacity, to the previously characterized endothelinA and endothelinB receptor. These receptors appear to be biologically active and mediate the contractile activity of the epididymis in vitro. Our data suggest that endothelin-1, via a paracrine mode of action, may be responsible for sperm progression through this organ.

Neuronal input from the inferior mesenteric ganglion (IMG) affects sperm transport within the rat cauda epididymis

Sympathetic nerves emanating from the inferior mesenteric ganglion (IMG) innervate the mammalian epididymis and vas deferens. We have reported previously that surgical removal of the rat IMG results in excessive accumulation of spermatozoa within the cauda epididymis. The objective of the present study was to determine whether sperm accumulation following IMG removal was due to a denervation-induced change in the rate of sperm transport within the cauda epididymis. In these studies epididymal sperm numbers were counted and used as a measure of sperm transport within the epididymis. In order to examine sperm transport within the cauda epididymis specifically, efferent duct ligation (EDL) was used to prevent further entry of testicular spermatozoa into the epididymis. Rats were divided into four treatment groups: sham-operated control, EDL alone for 7 days (EDL + 7), EDL alone for 14 days (EDL + 14), or EDL for 7 days at which time the IMG was removed and the rats were maintained for an additional 7 days (EDL + IMG). Epididymides were homogenized and the number of spermatozoa in the caput and cauda epididymis was counted. In EDL + 7 rats, the caput epididymis was devoid of spermatozoa. The rate of transit of spermatozoa through the cauda epididymis of EDL + 7 rats was approximately 3.43 million/day. The total number of cauda epididymal spermatozoa in EDL + 7 rats was reduced by 20% compared to sham-operated control rats. In EDL + 14 rats, spermatozoa transited the cauda epididymis at a rate of approximately 9.57 million/day, and the total number of spermatozoa in the cauda epididymis was reduced by 73% compared to sham-operated controls. If the IMG was removed 7 days following EDL, spermatozoa transited the cauda epididymis at a rate comparable to that observed in EDL + 7 rats (3.39 million/day). Following IMG denervation of EDL + 7 rats, cauda epididymal sperm numbers were maintained at levels observed in the EDL + 7 rats. These data demonstrate that the transport of spermatozoa through the cauda epididymis is influenced significantly by neuronal input from the IMG.

Effects of alpha-blocker on sperm concentration, motility, intraluminal pressure and fluid movement in the rat cauda epididymis

PURPOSE

To investigate whether alpha blocker has an effect on epididymal sperm parameters, intraluminal pressure and fluid movement.

MATERIALS AND METHODS

Sprague-Dawley rats were given daily oral doses 1 mg./kg., 2 mg./kg., or 10 mg./kg. of Bunazosin, a selective alpha blocker, for 1 month. A micropuncture technique was used to collect intraluminal fluids.

RESULTS

Epididymal sperm concentrations were significantly increased. Progressive motility of spermatozoa was not altered. Intraluminal pressures were significantly reduced, and intraluminal fluid movement rates were significantly increased.

CONCLUSION

Alpha blocker has an effect on sperm transport and storage in the rat testis and epididymis.

Intravasal injection of formed-in-place medical grade silicone rubber for vas occlusion

This paper describes two consecutive studies: a volume study and an efficacy study. The volume study determined the appropriated volume of Medical Grade Silicone Rubber (MSR) needed to achieve complete occlusion of the vas deferens. This was done by in-vitro testing of 130 human vas specimens containing plugs of MSR formed in vivo. The volume of MSR needed to occlude the vas was 0.1531 +/- 0.0059 ml injected by five to six turns of the applicator handwheel. There was a correlation between MSR volume, weight, and the number of turns of the applicator handwheel. An influence of body height upon the volume and weight of the MSR was also observed. An oval shaped clamp (15 mm long) was more effective in producing secure vas occlusion than was a round clamp (10 mm long). The mean outer diameter of the vas specimens was 1.80 +/0 0.15 mm, and the mean maximum dilated inner diameter was 0.93 +/- 0.11 mm. The efficacy study was a clinical trial to compare MSR was occlusion (using an oval 15 mm clamp and the appropriate volume derived from the volume study, n = 58) with no-scalpel vasectomy as the standard procedure (n = 64). The azoospermia rate following MSR vas occlusion was not significantly different from that following no-scalpel vasectomy, and was achieved in 3-6 months.

Sperm nuclear maturity in spinal cord-injured men: evaluation by acidic aniline blue stain

For many of the spinal cord-injured (SCI) men who are able to produce an ejaculate, infertility because of poor semen quality is a concern. Impaired spermatogenesis has been attributed as a possible reason for the poor semen quality. If so, events that occur during spermatogenesis may be used as a marker to evaluate the extent of spermatogenic alteration. During spermatogenesis, when the sperm nuclear condensation occurs, lysine-rich somatic histone are replaced by arginine-rich protamines in the DNA. Acidic aniline blue preferentially stains the immature sperm nucleus blue by binding to the lysine. Hence, each sperm can be individually evaluated for nuclear maturity. To test this concept, the nuclear maturity of sperm from 12 SCI men obtained by vibratory stimulation was compared with sperm samples obtained by self-masturbation from 104 non-SCI men. Sperm smears stained with acidic aniline blue were evaluated for nuclear maturity. The percent of unstained spermatozoa for non-SCI men (mean +/- SEM; 83.4 +/- 1.1%) was not statistically different from that of the SCI men (79.7 +/- 4.8%). However, the sperm motility (70.5 +/- 1.2%) and the percentage of normal sperm morphology (50.8 +/- 0.7%) of non-SCI men were significantly (P < .01) different from those of the SCI men (36.5 +/- 6.8% and 44.0 +/- 2.4%). It seems that the poor semen quality observed in SCI men is probably not caused by inadequate nuclear maturity of the spermatozoa.

Comparison of the effectiveness of placebo and alpha-blocker therapy for the treatment of idiopathic oligozoospermia

OBJECTIVE

To determine whether alpha-blocker (bunazosin) improves fertility and/or semen parameters

DESIGN

Placebo-controlled, double-blind clinical study.

SETTING

Nagoya University Hospital Andrology Clinic, Nagoya, Japan.

PATIENTS

Thirty-four men with sperm density between 5 and 20 x 10(6) sperm/mL, normal serum gonadotropins and T, and a fertile partner were enrolled in this study.

INTERVENTIONS

After a 3-month control period, patients randomly were prescribed bunazosin 2 mg/d or a placebo, two tablets per day, for 6 months. Semen and blood samples were collected before and after therapy. Semen parameters, serum gonadotropins, T, PRL, and E2 were evaluated before and after therapy.

RESULTS

The pregnancy rate (PR) in the alpha-blocker group was 25%, compared with 6.7% in the placebo group. There was no statistical difference in the PR between groups. The alpha-blocker group had significantly higher levels of sperm density and total motile sperm count. There were no differences between the placebo and alpha-blocker groups in seminal volume, the percentage of motile sperm, and normal morphology or hormone levels.

CONCLUSIONS

The authors conclude that alpha-blocker is a useful drug in the treatment of idiopathic moderate oligozoospermic men.

Objective assessment of spermatogenesis in men with functional and anatomic obstruction of the genital tract

Experimental rodent models simulating the condition of neurogenic infertility have drawn attention to the role of potential epididymal dysfunction as an underlying cause. This functional obstruction of the genital tract is comparable to the outcome of genital tract obstruction after vasectomy, and may explain the common finding of asthenospermia in both groups following either stimulated semen recovery or vasovasostomy, respectively. Since spermatogenic dysfunction has been reported in spinal cord injury, the relative roles of defective sperm production and sperm transport remain to be determined in men with neurogenic infertility. The objective of this study was to compare the levels of spermatogenesis in groups of vasectomized men and those with spinal cord injury, using objective measurement criteria for spermatogenesis. Groups of 10 spinal cord-injured and six vasectomized men matched for age and duration of disease, underwent incisional testicular biopsy. The specimens were divided equally for parallel quantitation of spermatogenesis by both quantitative cytometry and DNA flow cytometric analysis. Quantitative parameters showed similar values for both groups with reference to mean tubular wall thickness, mean tubular concentration of spermatids and Sertoli cells, as well as the mean spermatid: Sertoli cell ratio per tubule. Additionally, similar percentages of 1N, 2N and 4N cells, were found in both groups. Based on these preliminary findings this study provides a clinical correlation supporting the experimental observation that both anatomical and functional obstruction of the male genital tract exert a similar although minor spermatogenic insult, and that in both the putative cause for neurogenic infertility is more likely to be at the post-testicular level.

Influence of vas deferens mobilization on rat fertility: implications regarding orchiopexy

Children who undergo bilateral orchiopexy often have oligospermia or azoospermia in adulthood. This subfertility generally has been attributed to histological alterations in the cryptorchid testis. However, the possibility that an iatrogenic factor, such as mobilization of the vas deferens during orchiopexy, may have an adverse effect on fertility has not been studied. Six groups of mature Sprague-Dawley rats underwent right orchiectomy and the following procedures on the left side: group 1--sham operation, group 2--2 cm. of vas mobilized, group 3--4 cm. of vas mobilized, group 4--2 cm. of vas mobilized and deferential artery stripped off of vas, group 5--4 cm. of vas mobilized and deferential artery stripped off of vas and group 6--vasectomy. Each rat was then housed with 2 female rats for 24 days. Mobilization of the vas with disruption of the mesentery resulted in slight but statistically insignificant reduction in fertility. However, when the deferential artery was dissected off the vas, there was a marked reduction in fertility and fecundity. Histologically the vasa were normal without evidence of ischemic necrosis. The testes in groups 2 to 5 showed variable depletion of germ cells with shedding of germinal epithelium, and the testes and epididymides in group 5 were similar to the changes seen in vasectomized rats (group 6). No testes were necrotic. These data suggest that extensive mobilization of the vas causes subfertility in this animal model and may be secondary to a functional obstruction resulting from vas denervation. Whether a similar effect occurs during orchiopexy in humans deserves study.

The value of quantitative testicular biopsy and deoxyribonucleic acid flow cytometry in predicting sperm recovery from electrostimulated ejaculates

Spermatogenic abnormalities have been reported in the majority of men following spinal cord injury, and they contribute to the multifactorial etiology of reproductive dysfunction. Thus far, few have studied the seminiferous epithelium in this group of patients by objective criteria. While quantitative micrometry and flow cytometric analysis are accurate and reproducible methods of quantitating spermatogenesis, the latter is simpler and permits needle aspiration for tissue recovery. The objective of this study is to determine the value of quantitative micrometry and flow cytometric analysis as methods of predicting total sperm yield in electrostimulated ejaculates. Incisional testicular biopsy was performed in 12 anejaculatory men, and the tissue specimens were divided for analysis by quantitative micrometry and flow cytometric analysis. Quantitative micrometry consisted of determining the mean tubular wall thickness, mean tubular concentration of the Sertoli cells and mature spermatids in a minimum of 10 round seminiferous tubules per patient. Specimens were prepared for flow cytometric analysis and the deoxyribonucleic acid histogram was analyzed to determine the percentage of cells in each ploidy compartment. Of the quantitative micrometry parameters analyzed a significant correlation resulted between the total sperm yield per electroejaculate and the mean tubular concentration of late spermatids (p = 0.001) as well as with the mean tubular ratio of late spermatids to Sertoli cells (p = 0.003). The tubular concentration of spermatids resulted in a sensitivity and specificity of 100% and 75%, respectively, to predict adequate sperm yield in semen. Likewise, the mean tubular ratio of spermatids to Sertoli cells resulted in a sensitivity and specificity of 75% and 87.5%, respectively, in its ability to predict normal sperm yield in the recovered ejaculate. Deoxyribonucleic acid flow cytometry analysis showed a normal haploid compartment in all 6 specimens studied, and each was associated with high numbers of sperm in recovered semen. Quantitative histometric parameters correlate significantly with the total sperm yield obtained in electrostimulated ejaculates and may have a role in the selection of candidates for treatment in reproductive rehabilitation programs.

Origin of neurons supplying the vas deferens of the rat

Retrograde axonal tracing methods using Fluoro-Gold were used to examine the neuronal input to the vas deferens in the adult Wistar rat. The greatest number of labelled efferent neurons were found in the ipsilateral pelvic accessory ganglion (PAG) (68%) and the major pelvic ganglion (MPG) (15%). Fewer than 3% of labelled neurons were localized to the inferior mesenteric and sympathetic chain ganglia. Labelled neurons were also located in the ipsilateral L1, L2, and L6, S1 dorsal root ganglia (DRG), corresponding to afferents that travel in the hypogastric and pelvic nerves, respectively. Contributions from contralateral neurons in the PAG, MPG and L1 DRG were also documented. The role of afferents supplying the vas deferens is not known but they may relay nociceptive or mechanoreceptive input. Efferent input from peripheral ganglia probably contributes to contractility of the vas deferens based on previous investigations.

Characterization of adrenoceptors involved in the electrogenic chloride secretion by cultured rat epididymal epithelium

1. Short-circuit current (SCC) technique was used to study the adrenoceptors involved in the electrogenic chloride secretion by cultured cauda epididymal epithelium of rats. Stimulation of the epithelium with noradrenaline (primarily beta 1-adrenoceptor selective agonist), salbutamol (beta 2-adrenoceptor selective agonist) and adrenaline (non-selective beta-adrenoceptor agonist) led to a rise in SCC. At a low chart-speed (2 mm min-1), the response profile to these agonists consisted of a peak followed by a sustained response considerably higher than the basal SCC. 2. The EC50s (doses of agonist producing 50% maximum response) of noradrenaline, salbutamol and adrenaline were 300, 115 and 10 nM respectively. Pretreating the tissues with 1 microM atenolol (beta 1-selective antagonist) and 10 microM butoxamine (beta 2-selective antagonist) shifted the dose-response curves of noradrenaline (shifted EC50 = 4000 nM) and salbutamol (shifted EC50 = 1050 nM) to the right. Atenolol (1 microM) and butoxamine (10 microM) shifted the dose-response curve of adrenaline to the right with new EC50s of 30 nM and 115 nM, respectively. 3. The rapidly rising phase of the SCC response to noradrenaline and adrenaline observed at low chart-speed consisted of a brief and transient retraction followed by a rebound increase in SCC. At a high chart-speed (1 mm s-1), the retraction and rebound phenomenon manifested as a fast initial spike which could be blocked by phentolamine (non-specific alpha-adrenoceptor antagonist) in a dose-dependent fashion. Similar initial spikes were observed when the tissues were stimulated with phenylephrine (alpha-selective agonist) but not with isoprenaline (non-selective beta-agonist) or forskolin (activator of adenylate cyclase). The response of the initial spike triggered by noradrenaline was dose-dependent and the EC50 was 2000 nM.4. The present study showed that the electrogenic chloride secretion by rat epididymis could be stimulated by (alphaxi-, beta131- and beta2-adrenoceptor agonists. The al-mediated response had a faster onset and more transient action than the 3-counterpart. It is postulated that epididymal chloride secretion might be regulated by neural (noradrenaline-mediated) and humoral (adrenaline-mediated) controls and that the stimulus-secretion coupling mechanisms might involve both Ca2+(alpha-mediated response) and adenosine 3':5'-cyclic monophosphate (beta-mediated response) as intracellular second messengers.

The effect of semen quality of the electrical current and heat generated during rectal probe electroejaculation

Rectal probe electroejaculation is effective in procuring sperm from spinal cord injured patients with ejaculatory incompetence. The seminal quality in these patients is usually suboptimal and the motility is almost always low. We conducted an in vitro experiment to determine whether the heat and current generated during rectal probe electroejaculation impaired sperm motility or forward progression, or if the poor semen quality is the result of existing testicular dysfunction.

Quantitative testicular biopsy in spinal cord injured men: comparison to fertile controls

Spermatogenic abnormalities have been reported in the majority of spinal cord injured men on routine testicular biopsy. However, given the interim advances in their urological and rehabilitative care, a quantitative assessment of the germinal epithelium after spinal cord injury and comparison of these parameters to normal controls are warranted. Incisional testicular biopsy was performed in 14 spinal cord injured men. Quantitative micrometric techniques were applied to assess spermatogenesis and the results were compared to a normative data base of testicular biopsies previously obtained from a group of 15 fertile volunteers. From a minimum of 10 randomly selected round seminiferous tubules per subject the mean number of Sertoli cells, mature spermatids, tubular diameter and tubular wall thickness were determined in both groups and statistically analyzed. In the spinal cord injury group the mean number of spermatids per tubule was significantly lower and the mean number of Sertoli cells per tubule was significantly higher than in fertile controls (p less than 0.05). Moreover, the mean Sertoli cell-to-spermatid ratio per seminiferous tubule was significantly higher in the spinal cord injury group and discriminated between spinal cord injured men and controls, with a sensitivity of 93% and specificity of 100% (p less than 0.0001). Half of the spinal cord injury group showed a mean tubular spermatid density of less than 10. Compared to the fertile population, spinal cord injured men show significant differences in quantitative parameters of the germinal epithelium that may contribute to the reproductive dysfunction.