Secretory potentials in the submaxillary gland of the cat

Sympathetic nerve stimulation caused biphasic secretory potentials in cat submaxillary gland cells. The initial phase was a transient hyperpolarization. It was seldom seen after single shocks but nearly always occurred at high stimulation frequencies (10-20 Hz). It was imitated by phenylephrine and completely eliminated by dihydroergotamine or phentolamine and thus considered to be mediated via alpha-adrenoceptors. The late phase, a depolarization, was seen even at low stimulation frequencies and could often be evoked by single shocks. Both alpha- and beta-block reduced this response. Parasympathetic nerve stimulation evoked transient hyperpolarizations. The secretory potentials mediated via all the three receptors classes were paralleled by decreased input resistances across the acinar cell membranes.