MODIFICATION OF HYPOTHALAMIC-PITUITARY-ADRENOCORTICAL ACTIVITY BY SEROTONERGIC AGENTS IN THE RAT

The effects of tandospirone, enciprazine, gepirone, buspirone (5-HT1A agents) and carvotroline (5-HT2) on hypothalamic-pituitary-adrenocorti cal activity (HPA) activity were studied. These drugs increased the pl asma corticosterone levels in a dose-dependent manner. Their ED50 valu es were 3.8, 31.8, 3.1, 3.4 and 7.0 mg/kg, respectively. Drug effects peaked between 30 min and 1 h, and plasma corticosterone levels return ed to control levels after 2 h. When the drugs were given in conjuncti on with a rotatory stress, gepirone and enciprazine increased and carv otroline decreased plasma corticosterone levels. Dexamethasone (0.1 mg /kg) pretreatment reduced drug-activated HPA axis activity.