Acute treatment with alcohol affects calcium signaling and contraction associated with apoptosis in vas deferens of periadolescent rats.

Our purpose was to verify if alcohol causes alterations on translocation of Ca(2+) and tension induced by KCl or noradrenaline in vas deferens of periadolescent Wistar rats. A single dose of alcohol (i.p. 3.0g/kg) or saline as control, was given 4h before sacrifice. Longitudinal strips of prostatic portion were mounted in vitro for simultaneous measurements of intracellular Ca(2+) and contractions. Fluorescence and tension were measured in strips loaded with the fluorescent dye fura-2. The mean values (±S.E.M.) of fluorescence ratios (F340/380) evoked by KCl were significantly lower by about 70% after alcohol, in relation to control. It was about 50% lower when evoked by noradrenaline. In relation to tension, the respective mean values (±S.E.M.) were lower by about 60% in organs treated with KCl or by about 80% after noradrenaline. In some experiments, before noradrenaline contraction, the vas deferens was incubated with verapamil 10(-6)M for 30min. In these experiments, contractions by noradrenaline in the presence of verapamil were decreased by about 70% by alcohol. Alcohol decreases cytosolic calcium and contractility after KCl and noradrenaline, as compared with controls. In addition, alcohol promoted damage of lumen structures. Prostatic portion showed no striking morphometric change after treatment, but the number of TUNEL positive cells in muscular layer, basal lamina and lumen were increased by alcohol, indicating apoptosis, compared with controls. This investigation shows that alcohol treatment alters signaling of calcium which in turn compromises the contraction associated with a process of apoptosis of periadolescent rats.

Changes of cytosolic calcium and contractility of young rat vas deferens by acute treatment with amphetamine, fluoxetine or sibutramine.

Previous studies conducted in our laboratory indicated that administration of amphetamine, fluoxetine or sibutramine affects the sympathetic nervous system of the rat vas deferens. Therefore, our goal was to verify the role of calcium in vasa deferentia from young rats pretreated with a single dose of these drugs. Young 40-day-old male Wistar rats were pretreated with amphetamine 3 mg/kg, fluoxetine 10 mg/kg or sibutramine 6 mg/kg for 4 h before the experiments. CaCl(2) (10 mM) was used to induce contraction through time-effect curves in calcium-free solution to measure phasic and tonic components. We also evaluated the calcium-induced fluorescence of vas deferens cut into thin slices. In rats pretreated with amphetamine, we found an increase of the tonic contraction component which was reduced by verapamil. The phasic and tonic responses were increased in the group treated with fluoxetine, but only the tonic response was more sensitive to the antagonism by verapamil. The group treated with sibutramine showed an increase of phasic response whereas the tonic component was decreased. In this group an increase of the affinity for verapamil antagonism was found. In the calcium fluorescence study it was observed that the group treated with amphetamine, fluoxetine or sibutramine showed higher basal Ca(2+) fluorescence after stimulus with KCl (70 mM), noradrenaline (10(-4)M) or acetylcholine (10(-4)M). In all pretreated groups the calcium fluorescence was diminished by nifedipine 10(-7)M. Therefore, the pretreatment with amphetamine, fluoxetine or sibutramine seems to affect the calcium contractility and homeostasis in young rat vas deferens.