Parasympathetic Influence Plays an Independent and Significant Role in Inducing the Contraction of the Seminal Vesicle of the Rat

Ejaculatory Duct Obstruction Affects Seminal Vesicle Contractile Efficacy and Smooth Muscle Ultrastructure in a Rat Model

The purpose of this study was to investigate the effects of ejaculatory duct obstruction (EDO) on contractile efficacy, smooth muscle ultrastructure, and α1A and M3 receptors of rat seminal vesicles (SVs). A total of 48 male rats, aged 14-15 weeks, were randomly divided into three groups, namely, the control, complete EDO, and partial EDO. SV tissues were collected at 4 and 8 weeks postoperatively for further experiments. Results revealed a marked reduction in SV contractile efficacy over time following obstruction in the complete EDO group. The contractile force and frequency decreased and increased in the partial EDO group at week 4, respectively, whereas contractile efficacy significantly reduced at week 8. Moreover, obstruction resulted in significant downregulation in expression of α1A and M3 proteins and mRNAs in rats from the complete EDO group over time. Rats in the partial EDO group initially exhibited an increase followed by a decrease. Analysis of the ultrastructure of SV smooth muscles confirmed the above changes. In conclusion, complete EDO can lead to a progressive decrease in contractile efficiency of SVs. On the other hand, partial EDO can first compensate for the contraction of SVs and gradually decompensate afterwards.

Ejaculatory dysfunction in the treatment of lower urinary tract symptoms

The link between lower urinary tract symptoms (LUTS) secondary to benign prostatic hyperplasia (BPH) and sexual dysfunction is well established. Sexual dysfunction can encompass both ejaculatory dysfunction (EjD) and erectile dysfunction (ED). Ejaculatory dysfunction can consist of premature ejaculation, delayed ejaculation, retrograde ejaculation, anejaculation, decreased force of ejaculation and pain upon ejaculation. The impact of different medical and surgical therapies on ejaculatory function will be reviewed. We reviewed the various categories of LUTS treatment including the canonical epidemiology and pathophysiology as well as the surgical and medical treatments for LUTS/BPH. We note that most surgeries and several medical treatments have a certain but ill-defined negative impact on ejaculatory function. Several MISTs and selected medical therapies appear to have little impact on EjD. Both EjD and BPH are very common disorders in men under the care of an urologist. It is well documented that there is a clinical association between these two entities. Unfortunately many of the medical treatments and almost all surgical treatment impact the ejaculatory function of the patient. The surgical treatment of BPH often leads to retrograde ejaculation while medical treatment leads to anejaculation.

Effects of Silodosin and Tamsulosin on the Seminal Vesicle Contractile Response

OBJECTIVES

To understand the mechanisms underlying ejaculation dysfunction caused by α1A-adrenocetor (AR) antagonists, the effects of α1A-AR antagonists on the contractile responses of the seminal vesicle were investigated.

METHODS

Isolated seminal vesicles from guinea pigs were cannulated and pressurized, and the changes in the intraluminal pressure were recorded. Periodic applications of electrical stimulation (ES) caused biphasic increase in the intraluminal pressure, that is, initial and subsequent contractions. The effects of silodosin and tamsulosin, α1A-AR antagonists, on the contractile responses were examined.

RESULTS

The ES-induced biphasic contractions were blocked by tetrodotoxin (TTX). Silodosin and tamsulosin suppressed the initial contractions in a dose-dependent manner, while also exerting various inhibitory effects on the subsequent contractions. Increases in the intraluminal pressure facilitated spontaneous phasic contractions. The spontaneous contractions were not affected by TTX or α1A-AR antagonists, but were abolished by nifedipine.

CONCLUSIONS

The initial contractions triggered by neuronal excitations were suppressed by silodosin and tamsulosin, suggesting that the ejaculation dysfunction may be attributed to the α1A-AR antagonist-mediated suppression of nerve-evoked contractions in the seminal vesicle. The subsequent contractions may be induced by mechanical stimulation associated with the initial, nerve-evoked contractions. Alternatively, other transmitters may be involved to various degrees in the neuromuscular transmission of the seminal vesicle.

New Methodology for Investigating Ejaculation Dysfunction: Measuring Intraluminal Seminal Vesicle Pressure in Rats with a Telemetric Device

INTRODUCTION

Ejaculation dysfunction is one of the most common male sexual disorders. Despite its prevalence and adverse impact on patients, little attention has been given to investigating ejaculation dysfunction.

AIM

We introduce a new method for evaluating ejaculation dysfunction in rats with a telemetric device.

METHODS

A pressure transducer was surgically implanted in the seminal vesicles of 7-week-old male Sprague-Dawley rats. One week later, the rats were subcutaneously administered tamsulosin 3 μg/kg, and intra-seminal vesicle pressure (ISVP) was recorded in freely moving rats after an injection of apomorphine (80 μg/kg). Same rats repeated experiment with tamsulosin 10 μg/kg, silodosin 1 mg/kg, and normal saline with 3-day intervals.

MAIN OUTCOME MEASURE

Sexual events were visually identified and recorded. Ejaculation was confirmed by visualization of a copulatory plug in the tip of the penis. We compared the maximal ISVP and area under the curve (AUC) of the ISVP.

RESULTS

Adequate ISVP data were easily recorded and available in 66.6% rats (10/15) over a 6-week telemetric recording period (12 recordings). The mean number of ejaculations during an inspection time of 30 minutes was 1.5 ± 0.1. The maximal ISVP values in rats receiving 3 μg/kg (30.0 ± 5.2 mm Hg) and 10 μg/kg tamsulosin (15.1 ± 1.6 mm Hg) and 1 mg/kg silodosin (12.9 ± 2.2 mm Hg) were significantly lower than that in control rats (61.4 ± 13.4 mm Hg, P < 0.05). The AUC values in rats receiving 3 μg/kg (72.7 ± 18.9 mm Hg × s) and 10 μg/kg tamsulosin (23.5 ± 6.1 mm Hg) and 1 mg/kg silodosin (23.9 ± 8.0 mm Hg) were also lower than that of control rats (162.6 ± 34.3 mm Hg, P < 0.05).

CONCLUSIONS

Telemetric ISVP assessment is reliable and feasible for investigating apomorphine-induced ejaculation in rats. Tamsulosin (3 μg/kg and 10 μg/kg) and silodosin 1 mg/kg decreased the ISVP during ejaculation.

The role of sympathetic and parasympathetic nerve systems on the smooth muscle of rat seminal vesicles - experimental results and speculation for physiological implication on ejaculation

Ejaculation is a process involving sympathetic and parasympathetic effects during different stages - emission and ejection. Some conditions of ejaculation dysfunction are associated with autonomic nerves. However, the exact effects of autonomic nerves on ejaculation are not well defined. Autonomic agonists induce different recorded trace patterns of seminal vesicular contraction. The different traces contain different components of phasic and tonic contraction, which may have physiological implications. In this study, we examined isolated rat seminal vesicle (SV) contraction by phenylephrine (PE), acetylcholine, and their respective antagonists and then speculated upon physiological roles of sympathetic and parasympathetic nerves on SV during ejaculation. We found that PE and Ach both achieved good contraction of rat SV. Compared to α1b for sympathetic and M1, M2 for parasympathetic receptors, α1a and M3 are the relatively dominant subtypes on rat SV. Adrenergic and cholinergic agonists cause different trace patterns of SV contraction. We speculated that the sympathetic effect is dominant during emission to squeeze seminal fluid out and that the parasympathetic effect is dominant during ejection to provide an anti-reflux effect on the ejaculatory duct.