Influence of the acute stress on agonist-stimulated phosphoinositide hydrolysis in the rat cerebral cortex

Abstract

1. The present study was carried out in order to elucidate the influence of the acute stress on alpha 1-adrenergic, serotonin-2 (5-HT2) and muscarinic cholinergic (M-Ach) receptors-mediated phosphoinositide (PI) hydrolysis in rat cerebral cortex slices. 2. In rat cerebral cortex slices, noradrenaline (NA), serotonin (5-HT) and carbachol stimulated [3H]inositol-monophosphate (IP1) accumulation in a concentration-dependent manner. 3. The forced swimming test (FST) for 15 min induced a significant reduction of 5-HT-stimulated [3H]IP1 accumulation, but this stress situation did not produce a significant alteration of NA- and carbachol-stimulated [3H]IP1 accumulation. 4. The FST for 15 min did not affect the density and affinity of alpha 1-adrenergic, 5-HT2 and M-Ach receptors. 5. In a mild acute stress situation, the intracellular signal transduction mediated by 5-HT was promptly inhibited as compared to the signal transduction mediated by NA or carbachol. This inhibition may be induced by an acute uncoupling of 5-HT2 receptor-mediated intracellular signal transduction.