Catecholaminergic responses in vas deferens isolated from rats submitted to acute swimming stress

The study was performed to examine the responses to catecholamines in vas deferens isolated from rats submitted to acute swimming-induced stress. It was demonstrated that acute stress induces a significant subsensitivity of rat vas deferens to norepinephrine. This subsensitivity was inhibited when the experiment was carried out in the presence of either cocaine (10-5 M) or timolol (10-5 M). On the other hand, the rat vas deferens sensitivity to methoxamine was significantly increased by acute swimming-induced stress. Thus, despite acute swimming stress inducing a reduction in response to norepinephrine, the alpha1-adrenoceptor-mediated contractile response was increased. Additionally there were increases in neuronal uptake and beta2-adrenoceptor activity that opposes the alpha1-adrenoceptor activity. Integrated, these phenomena are responsible for the rat vas deferens subsensitivity to norepinephrine which may be involved in body homeostasis in stressogenic situations.