The effect of domperidone on the electrical response of cockroach salivary gland acinar cells

Abstract

The effects of domperidone on the electrical response of the cockroach salivary gland to applied dopamine and to nerve stimulation have been investigated. Dopamine and nerve stimulation induced a hyperpolarization of the salivary gland acinar cells, which was occasionally followed by a depolarization. At 1 and 10 microM domperidone had no effect on the responses; however, at higher concentrations domperidone (50 and 100 microM) potentiated the hyperpolarization induced by both dopamine and nerve stimulation. Domperidone (50 microM) also potentiated the hyperpolarization induced by 5-HT. Thus the potentiation probably results from a post synaptic action independent of either the dopamine or 5-hydroxytryptamine receptor. In addition, domperidone (50 and 100 microM) had two delayed effects; one, presynaptic, led to a reduction in the response to nerve stimulation; the other, postsynaptic, led to the abolition of the depolarizing phase of the response.