Calcium channel blockade and contractile responses in the isolated human vas deferens

The effects of removal of extracellular calcium and of the calcium channel blockers nifedipine, verapamil and diltiazem were studied on contractions induced by electrical field stimulation and high K+-solution in isolated preparations of the human vas deferens. Electrically induced contractions were blocked by tetrodotoxin and alpha-adrenoceptor blockade. They were abolished in calcium-deficient medium, and suppressed by the calcium channel blockers in the order of potency nifedipine greater than verapamil greater than diltiazem. The maximum blocking effect of nifedipine was approximately 40%. All the blockers practically abolished K+-induced contractions. It is concluded that even if the contractile response of the human vas deferens to electrical stimulation is dependent on extracellular calcium, calcium channel blockers seem to have only a limited effect on this contraction and their capability of impairing the function of the vas deferens in patients is questioned.     

Cutaneous fistulas to the vas deferens.

Cutaneous fistulas to the vas deferens are a rare occurrence. A careful review of the literature revealed only 16 cases reported within the last 70 years. We present a case of such a fistula occurring after inguinal orchiectomy for suppurative epididymo-orchitis and review the etiologies of all reported cases to provide recommendations for management.     

Effect of histamine on human vas deferens in vitro

Histamine, 2-methylhistamine and 4-methylhistamine produced concentration-related contractions in some isolated human vas deferens preparations. The contractions produced by histamine and its analogues were reversibly and competitively antagonised by the H1-receptor blocker, mepyramine, but not the H2-receptor blockers, burimamide and cimetidine. Phentolamine, atropine and guanethidine did not affect the excitatory action of histamine. Histamine and 4-methylhistamine did not show any inhibitory effect on KCl-induced tone. The results showed that histamine receptors were present in the human vas deferens and the histamine receptors mediating the excitatory response were likely to be H1-receptors.     

Ectopia of the vas deferens

Ectopic location of the vas deferens is a rare congenital abnormality that has a spectrum of presentations. Such cases have been associated with anorectal anomalies. Knowledge of distal Wolffian duct embryology may help to explain the developmental steps involved in these anomalies, as well as provide theories for the variations that may be encountered. Vas deferens development is reviewed, and two cases of vas ectopia are presented to illustrate and lend support to current theories of normal and abnormal vasal embryology.     

Physiology of the vas deferens

Summary Seminal emission occurs in response to rhythmic contractions of male secondary sex organs, including the vas deferens. Although contraction of the vas is directly due to adrenergic mechanisms, numerous substances modulate the release of norepinephrine from sympathetic pathways. These substances include local endogenous factors and neurotransmitters such as acetylcholine and NPY. Many substances are capable of altering the contractility of the vas deferens by modulating neural transmitter release or the basal tone of this smooth muscle. Because multiple pathways and substrates are capable of affecting its contractility, it is not surprising that drugs and metabolic disorders influence the function of the vas deferens and, ultimately, male fertility.     

Reconstruction of vas deferens

If the vas deferens repair operation is done in properly selected pa tients, it is possible to achieve success in 50% of cases. The method o f reconstruction used by the author is outlined and technical difficulti es are indicated. The longer the time interval between vasectomy and the repair operation, the less the chances of success. Where the interval is more than 5 years, a preliminary testicular biopsy is advised. It is better to limit the operation to patients below the age of 45 years. Care must be taken to avoid injury to blood vessels. End- to-end union of cut ends without tension must be made over an indwelling splint. The splint is removed after 6 days. When sufficient length of the vas is not available for repair without tension, a mobilization of the vas may be done similar to what is done in cases of undescended testicle. When the distal end of the vas is too short or stenosed, a vasoepididymal anastomosis may be possible. Placing a splint in these cases has been advocated also. It is better to do the operation on 1 side only. If spermatozoa are absent after 3 months, the other side may then be operated on.     

Inhibitory effect of serotonergic drugs on contractile response of the rat vas deferens to electrical nerve stimulation: in vivo study

PURPOSE: To evaluate, in vivo, the inhibitory effects of certain serotonergic drugs on the contractile response of the rat seminal tract to electrical stimulation of the hypogastric nerve. MATERIALS AND METHODS: Twenty-five Sprague Dawley rats (250 to 300 gm. each) were equally divided into 5 groups based on experimental agent; normal saline, clomipramine, sertraline, paroxetine, and fluoxetine. The hypogastric nerve was electrically stimulated and the intraluminal pressure of the vas deferens was measured, both pretreatment and 30 minutes after intravenous injection of four different doses (0.1 to 20 x the therapeutic dose) of each agent. Variations of responses relative to the time after administration of each agent (at 10- and 20-fold concentration) were also observed. RESULTS: All serotonergic drugs caused dose-dependent inhibition of elevation in intraluminal pressure of the vas deferens (p <0.05). The inhibitory effect of clomipramine was significantly better (p <0. 05) than that of fluoxetine at a 1-fold dose, while no significant differences were noted among clomipramine, sertraline and paroxetine. At doses of 10- and 20-fold, clomipramine had the strongest inhibitory effect, followed by sertraline and paroxetine, then fluoxetine (p <0.05). No differences were found in the inhibitory effects of the drugs studied, as a function of the time after injection. CONCLUSIONS: Clomipramine was the most potent drug for inhibition of elevation in intraluminal pressure of the rat vas deferens induced by electrical stimulation of the rat hypogastric nerve. The stronger inhibitory effect of clomipramine than the selective serotonin reuptake blockers suggests a possible peripheral action of clomipramine in addition to its central serotonergic action.     

On the surgery of the vas deferens

Vasectomy is an effective measure preventing postoperative epididymectomy in prostatic and urethral surgery. The reasons why it proves sometimes ineffective are discussed. The stumps of the divided vas should be exteriorised in order to obviate complications which may arise when the stumps are burried in the scrotum. Various methods of temporary reversible occlusion of the vas were tried in prostatic patients as substitutes for vasectomy. The results of those attempts are presented. The technique of vasectomy is presented in which the stumps of the severed vas are exteriorised. Reasons for this procedure are given. Various methods were tried to produce temporary and reversible occlusion of the vas instead of vasectomy. The most promising way seems to be the ligature of the vas which is then exteriorised and wrapped with skinflap.     

Presentation of fused vas deferens

Transverse testicular ectopia is a rare condition that usually presents as a unilateral nonpalpable testis and a contralateral descended testis with an associated hernia. Currently, with the use of diagnostic laparoscopy, transverse testicular ectopia is found before groin exploration. We reviewed 2 cases that were referred to our institution. Both patients had a common vas deferens with proximal fusion. To our knowledge, a fused vas deferens has only been reported three other times in published reports. Our second case is unique in that this is the first time a common vas deferens has been reported outside of transverse testicular ectopia.     

Age-related changes in contractile force of rabbit detrusor muscle to prostaglandin E1, E2 and F2 alpha

Contractile responses of urinary bladder muscle strips to prostaglandin (PG) E1, E2 and F2 alpha were compared in young and old rabbits. All PGs tested caused an increase in contractile force of urinary bladder muscle strips from young (3 weeks) and old (greater than 2 years) rabbits. The contractile response was most marked with PGE2 at concentrations of 10(-10)-10(-7) M in muscle strips from both young and old rabbits. At a high concentration (10(-5) M), the contractile response was most marked with PGF2 alpha in young rabbit bladder muscle strips, whereas in old rabbit bladder muscle strips the magnitude of the responses to PGE2 and PGF2 alpha were equal at 10(-6) M and both were greater than the response to PGE1. The contractile response to PGE1 was greater in old detrusor than in young detrusor at concentrations greater than or equal to 10(-6) M, whereas the contractile response to PGE2 (10(-7)-10(-5) M) and PGF2 alpha (10(-6)-10(-5) M) were greater in young detrusor than in old detrusor. These data show that rabbit detrusor muscle shows a contractile response to PGE1, E2 and F2 alpha and that the magnitude of these responses vary with age.