Carbamazepine inhibits the potentiation by adenosine analogues of agonist induced inositolphosphate formation in hippocampal astrocyte cultures

Carbamazepine (CBZ) resembles lithium in its beneficial effects in therapy and prophylaxis of affective disorders. Since lithium is presumed to act via an attenuation of the inositolphos-phate/Ca2+-second messenger system, it is of particular interest whether or not CBZ might also have inhibitory effects on this type of signal transduction. CBZ is an antagonist of adenosine A1-receptor subtypes. We show here that activation of adenosine A1-receptors potentiates the phenylephrine induced formation of inositolphosphates in hippocampal astrocytes and that this potentiating effect is inhibited by CBZ at a therapeutically relevant concentration. These results indicate that CBZ can by antagonism of adenosine A1-receptors inhibit the inositolphosphate/Ca2+-signalling in neural pathways regulated by adenosine.