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Introduction Corporal smooth muscle relaxation is mediated mainly but not completely by nitric oxide. Endocannabinoids modulate the various neurotransmitter systems. Aim In the present study, a possible role of endocannabinoids on non-nitrergic nonadrenergic noncholinergic (NANC)-mediated relaxations was investigated. Methods In precontracted tissues, control electrical field stimulation (EFS)-induced NANC relaxation responses were obtained using varying frequencies of stimulation in the presence of L-arginine methyl ester (L-NAME), guanethidine, and atropine. To investigate the effects of cannabinoids on EFS-evoked non-nitrergic NANC relaxation responses, a similar experimental procedure was applied in the presence of cannabinoid receptor antagonists AM251 or AM630; vanilloid receptor antagonist capsazepine; or cannabinoid receptor agonists anandamide, arachidonyl-2-chloroethylamide (ACEA), or JHW015. Main Outcome Measures Effects of cannabinoid receptor antagonists and agonists on EFS-evoked non-nitrergic NANC relaxation responses. Results L-NAME abolished EFS-induced relaxation responses at lower frequencies (2–4 Hz) and inhibited the relaxation responses at higher frequencies (8–32 Hz). AM251 and AM630 either together or separately inhibited, whereas anandamide, ACEA, and JHW015 enhanced non-nitrergic NANC relaxation responses. Anandamide did not alter EFS-induced non-nitrergic NANC relaxations in the presence of AM251 and AM630. Capsazepine enhanced non-nitrergic NANC relaxation responses. Conclusion These results suggest that non-nitrergic NANC relaxations may be mediated partially by cannabinoid-like neuronal factors acting at both cannabinoid CB1 and cannabinoid CB2 receptors.

It is not known whether there is an impairment in vas deferens motility after unilateral testicular torsion/detorsion. Therefore, we aimed to determine whether the electrical field stimulation (EFS)-evoked biphasic contractions are altered in ipsilateral and contralateral rat vasa deferentia obtained from animals exposed to the unilateral testicular torsion/detorsion procedure. We also evaluated the effects of melatonin (MLT), which is a strong antioxidant, on these contractile responses. Rats were subjected to torsion of the left testis for 2 h and then detorsion was performed. Contractility studies were carried out 2 h or 24 h after detorsion. Vas deferens strips were prepared from both the ipsilateral and the contralateral site 2 h or 24 h after the detorsion procedure to record EFS-evoked biphasic twitch responses. The same experimental protocol was repeated for the MLT-treated rats. Both phases of EFS-evoked contractions were decreased after torsion/detorsion in the ipsilateral vas deferens. MLT treatment increased torsion/detorsion-induced reduction of both phases of contractions after 2 h and 24 h. In the contralateral vas deferens, the first phase of EFS-evoked contractions was not changed, while the second phase of contractions was diminished 2 h and 24 h after detorsion. Although MLT decreased the second phase of contractions 2 h and 24 h after detorsion, it reduced the first phase of contractions only 2 h after detorsion. These results suggest that MLT produces an inhibition on EFS-evoked biphasic twitch responses in the ipsilateral and contralateral rat vasa deferentia following unilateral testicular torsion/detorsion in the rat.

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The results suggest that long period of tourniquet application altered endothelium-dependent muscarinic receptor-mediated relaxation responses. This is the first functional study that examined the effects of tourniquet application on corpus cavernosum tissue. In conclusion, it can be suggested that if tourniquet is necessary in penile surgery the application time of up to 20 min is more appropriate instead of prolonged usage.