Nicotine in High Concentration Causes Contraction of Isolated Strips of Rabbit Corpus Cavernosum

It is well known that cigarette smoke can cause erectile dysfunction by affecting the penile vascular system. However, the exact effects of nicotine on the corpus cavernosum remains poorly understood. Nicotine has been reported to cause relaxation of the corpus cavernosum; it has also been reported to cause both contraction and relaxation. Therefore, high concentrations of nicotine were studied in strips from the rabbit corpus cavernosum to better understand its effects. The proximal penile corpus cavernosal strips from male rabbits weighing approximately 4 kg were used in organ bath studies. Nicotine in high concentrations (10(-5)~10(-4) M) produced dose-dependent contractions of the corpus cavernosal strips. The incubation with 10(-5) M hexamethonium (nicotinic receptor antagonist) significantly inhibited the magnitude of the nicotine associated contractions. The nicotine-induced contractions were not only significantly inhibited by pretreatment with 10(-5) M indomethacin (nonspecific cyclooxygenase inhibitor) and with 10(-6) M NS-398 (selective cyclooxygenase inhibitor), but also with 10(-6) M Y-27632 (Rho kinase inhibitor). Ozagrel (thromboxane A2 synthase inhibitor) and SQ-29548 (highly selective TP receptor antagonist) pretreatments significantly reduced the nicotine-induced contractile amplitude of the strips. High concentrations of nicotine caused contraction of isolated rabbit corpus cavernosal strips. This contraction appeared to be mediated by activation of nicotinic receptors. Rho-kinase and cyclooxygenase pathways, especially cyclooxygenase-2 and thromboxane A2, might play a pivotal role in the mechanism associated with nicotine-induced contraction of the rabbit corpus cavernosum.

Relaxing Effect of Acetylcholine on Phenylephrine-Induced Contraction of Isolated Rabbit Prostate Strips Is Mediated by Neuronal Nitric Oxide Synthase

PURPOSE: The location of acetylcholinesterase-containing nerve fibers suggests a role for acetylcholine in both contractility and secretion in the prostate gland. The colocalization of nitrergic nerves with cholinergic nerves, and the cotransmission of nitric oxide with acetylcholine in cholinergic nerves, has been demonstrated in the prostate glands of various species. Thus, we investigated the effects of acetylcholine on phenylephrine-induced contraction and the correlation between cholinergic transmission and nitric oxide synthase by using isolated prostate strips of rabbits. MATERIALS AND METHODS: Isolated prostate strips were contracted with phenylephrine and then treated with cumulative concentrations of acetylcholine. Changes in acetylcholine-induced relaxation after preincubation with NG-nitroarginine methyl ester, 7-nitroindazole, and aminoguanidine were measured. The effects of selective muscarinic receptor antagonists were also evaluated. RESULTS: In the longitudinal phenylephrine-contracted strip, the cumulative application of acetylcholine (10(-9) to 10(-4) M) elicited a concentration-dependent relaxation effect. Acetylcholine-induced relaxation was inhibited not only by nitric oxide synthase inhibitors (10 microM L-NAME or 10 microM 7-nitroindazole) but also by 10 microM atropine and some selective muscarinic receptor antagonists (10(-6) M 11-([2-[(diethylamino)methyl]-1-piperdinyl]acetyl)-5,11-dihydro-6H-pyrido[2,3-b][1,4]benzodiazepine-6-one and 10(-6) M 4-diphenylacetoxy-N-methyl-piperidine). In contrast, relaxation was significantly increased by pretreatment of the strips with 10 mM L-arginine. CONCLUSIONS: Acetylcholine relaxed phenylephrine-induced contractions of isolated rabbit prostate strips. This relaxation may be mediated via both cholinergic and constitutive nitric oxide synthase with both the M2 and M3 receptors possibly playing key roles.

The Effects of 5-alpha Reductase Inhibitor on Contr action of Erectile Tissue and Secretion of Seminal Fluid in Male Rabbits: Preliminary Study / 대한남성과학회지

PURPOSE: Adverse sexual experiences such as erectile dysfunction (ED), loss of libido, and ejaculation disorders have been consistent side effects of 5-alpha reductase inhibitors (5ARI). The aim of this study was to evaluate the effects of 5ARI (finasteride) treatment on semen parameters and contraction of the corpus cavernosum and seminal vesicles in male rabbits. MATERIALS AND METHODS: Adult male New Zealand White rabbits (n=10) were randomized into 2 groups: finasteride-treatment (5ARI) group and vehicle-treatment (control) group. The 5ARI group received daily oral finasteride (10 mg/day) by gavage for 4~6 weeks, and the control group received the same concentration of the vehicle. The semen volume and semen parameters between the 2 groups were compared; thereafter, contraction or relaxation responses of smooth muscle strips of the corpus cavernosum and seminal vesicles were observed in an organ bath. RESULTS: Semen magnesium (14.2 vs 5.1 mg/dl) and protein (2.2 vs 1.6 g/dl) concentrations were significantly lower in the 5ARI group than in the control group. The concentrations of other parameters such as electrolytes (Na/K/Cl), fructose, and citrate did not differ between the 2 groups. The contractile responses to norepinephrine (NE) significantly increased in the 5ARI group compared to the control group and the relaxation responses to acetylcholine (ACh) or sodium nitroprusside (SNP) also increased in the 5ARI group. The contractile responses of the seminal vesicular strips to NE significantly decreased in the 5ARI group compared with the control group. CONCLUSIONS: The results suggest that finasteride may decrease contraction of seminal vesicle tissue and alter semen parameters. The effect of finasteride on erectile tissue was double-faced; enhancing both contraction and relaxation. Further study is needed in this respect.

Bilateral Recurrent Thigh Abscesses for Five Years after a Transobturator Tape Implantation for Stress Urinary Incontinence

The synthetic, tension-free midurethral sling procedure using transobturator tape (TOT) was introduced in 2001 and has become the most widely used procedure for the treatment of female urinary incontinence worldwide. However, infectious complications associated with erosions have occasionally been reported because of a foreign body reaction to the polypropylene mesh. We observed a case of a bilateral recurrent thigh abscess manifesting 5 years after a TOT sling procedure. The patient had recurrent thigh abscesses with repeated incisions and drainages in the past 1 year. Five months earlier, she had undergone a procedure to remove the eroded suburethral mesh, but incompletely. The right thigh abscess recurred, and ultimately the residual mesh was completely excised with abscess drainage. Complete mesh removal is very important to prevent abscess recurrence, and it is necessary for any urologist treating women who have undergone the TOT procedure to be aware of the possibility of abscesses occurring for a long time after the operation.