Yuh-Chen Kuo

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.

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

OBJECTIVES The role of the parasympathetic pathway in seminal vesicle (SV) contraction has not been well described. The purpose of this study was to study parasympathetic effects, the dominant muscarinic receptors subtype(s), and nitric oxide (NO) effects for SV contraction. METHODS In vivo, SV pressure of mature male Wistar rats were recorded after electric stimulation (ES) of each pelvic nerve (PN; parasympathetic pathway) alone; bilateral PNs simultaneously, the L6 and S1 branches of the left PN; the left PN after ablation of sympathetic influence; the lesser splanchnic nerve (LSN) after ablation of parasympathetic influence; and the LSN after pretreatment of 4 muscarinic receptor antagonists or a NO donor-3-Morpholinosydnonimine (SIN-1). RESULTS ES to the left PN caused frequency-dependent SV contraction, with similar results after ES to the right PN and bilateral PNS. ES to the L6 branch of the left PN caused significantly greater SV response than to the S1 branch. Ablation of sympathetic influence did not affect SV response to parasympathetic stimulation and vice versa. The inhibitory effects of 4-DAMP (M3 antagonist) and atropine (nonselective muscarinic antagonist) on SV response to ES were similar and significantly greater than those of pirenzepine (M1 antagonist) and methoctramine (M2 antagonist). Pretreatment of SIN-1 partially suppressed the SV response of ES to left PN. CONCLUSIONS ES via the parasympathetic pathway independently induces contraction of rat SV; NO partially suppresses the SV pressure response to parasympathetic ES.

Determination of Human Penile Electrical Resistance and Implication on Safety for Electrosurgery of Penis

INTRODUCTION Electrosurgery has been a surgical application since the late 19th century. Although many urologists take this daily application for granted, the effects of electrical treatment on penile nerves and vessels have not been well documented. AIM To investigate the electrical characteristics of the penis and erectile tissues and to discover the potential hazards of electrosurgery on the penis. METHODS Measurement of the electrical characteristics of three human penises in order to create models to analyze the effect of electricity on penile nerves and vessels. MAIN OUTCOME MEASURES Electrical resistivity of the penile shaft, electrical current density, and electric field strength on penile nerves and vessels, proportion of generated heat on the penis and electrical current density of the electrosurgery return electrode. RESULTS Electrical resistivity (ρ) of the penile shaft is 127.14 Ω · cm at 500 kHz. Electrical current density (J) of the penis shaft is 71.06 mA/cm(2) , nerve (60.23 mA/cm(2) ), vessel (67.93 mA/cm(2) ), and return electrode (2.11 mA/cm(2) ). Electrical field strength (E) of the whole penis shaft is 9.03 volt/cm. The proportion of generated heat on the penis is four times as much as on other body parts of the circuit. CONCLUSIONS Potential and subclinical injury to erectile tissue caused by electrosurgery on the penis cannot be underestimated. The injury mechanism can be attributed to a thermal (electrical current) effect and a nonthermal (mainly electrical field) effect. Ways to avoid the electrosurgical injury are: using less power (W)/electrical field and less time, biopolar electrosurgery confining the injured area, ligation to achieve hemostasis, and new laser technologies.

Clinical Study of Oral Trazodone in the Treatment of 25 Impotent Patients

Trazodone is an oral antidepressant that has been reported to prolong erections of potent men and to improve erections of impotent patients. We administered 50 mg trazodone three times a day to twenty-five impotent patients. Four patients discontinued the medication within the first week due to severe drowsiness in three patients and difficulty in urination in one. Of the re-maining 21 patients, four were diagnosed with psychogenic impotence and 17 with organic im-potence. After four weeks of medication, the results were evaluated by questionnaires. The overall response rate to the mediction was 52.4%. Among the patients with organic impotence, there was no significant difference in response to the medication between the differ-ent age groups. However, the overall response rate to the medicaton was much higher in the patients who were impotent for 18 months or less (75.0%) than in the patients who suffered from impotency more than 18 months (22.2%, p=0.0296). There was no obvious change n libido in thse patients. Side effects included a high percentage of drowsiness (84%), weakness (48%), dry mouth (40%) and blurred vision (24%). Impaired renal function also occurred in two patients. In conclusion, trazodone is effective for some mpotent patients. It was more effective in treating patients who suffered from impotency for 18 months or less. Thus, the earlier impotence is diagnosed the better chance there is for successful treatment. Te side effects should be moni-tored carefully. A large double-blind series is needed to confirm the results and determine the optimal dose of trazodone. (J Urol R.O.C., 9:7-11,1998)