[Maximal response of the rat vas deferens. II. Studies on the effect of variations in external K+ and the response to noradrenaline of preparations which were depolarized and exposed to various concentrations of extracellular Ca+].

The mechanical response of the rat vas deferens observed following administration of single or cumulative doses of K+ was studied and then the influence of external Ca2+ on the K+ response was investigated. The response of the preparation to noradrenalin when the concentration of K+ and/or Ca2+ is different from the physiological one was also studied. The results indicate that the ability of K+ to increase free intracellular Ca2+ concentration is greater than that of noradrenalin; there is an increase in the maximal response to noradrenalin on increasing the external concentration of K+ and/or Ca2+.