Action of dopamine and serotonin on the membrane potential of cultured astrocytes

The actions of dopamine, apomorphine and serotonin on the membrane potential of cultured astrocytes from rat spinal cord and striatum were examined. All three compounds caused a hyperpolarization of the majority of astrocytes tested. A small number of cells was depolarized and on a relatively large number of cells the amines had no effect. The dopamine antagonists cis-flupenthixol and domperidone reversibly blocked the effects of dopamine whereas the action of serotonin was antagonized by ketanserin. It is therefore concluded that the effect of both amines are due to activation of specific dopamine and serotonin receptors, respectively. Our electrophysiological data together with autoradiographic binding studies provide evidence that astrocytes possess receptors for dopamine and serotonin in addition to adrenoceptors and histamine receptors.