ELECTROPHYSIOLOGICAL EVIDENCE FOR THE PRESENCE OF RECEPTORS FOR CHOLECYSTOKININ AND BOMBESIN ON CULTURED ASTROCYTES OF RAT CENTRAL-NERVOUS-SYSTEM

The action of cholecystokinin (CCK) and bombesin (Bom) was studied on the membrane potential of astrocytes in explant cultures of rat cortex , cerebellum, brain stem and spinal cord. Both peptides (10(-8) and 10 (-7) M) caused a hyperpolarization of most astrocytes studied. The hyp erpolarization by CCK was markedly reduced or blocked by the CCKB-anta gonist L-365,260 whereas addition of the Bom-antagonist [D-Phe(12),Leu (14)]-Bom antagonized the effects of Bom, suggesting a specific action of these peptides. When CCK and Bom were tested on the same cell, bot h peptides were effective, indicating a colocalization of receptors fo r CCK and Bom on the glial membrane. Our electrophysiological investig ations provide strong evidence for the existence of functional CCK and Bom receptors on astrocytes.