PRESUMED ISOLATION STRESS BUT NOT RESERPINE AFFECTS CEREBRAL VASOACTIVE INTESTINAL POLYPEPTIDE (VIP) IN THE RAT

The concentration of Vasoactive Intestinal Polypeptide (VIP) was exami ned in rats in prefrontal cortex, occipital cortex, hippocampus, and h ypothalamus 24 h (short-term) and 21 days (long-term) after a single I P injection of reserpine (4 mg/kg). Reserpine treatment induced no cha nges in cerebral VIP, neither in the short-term nor in the long-term g roup. VIP content of the prefrontal cortices of the long-term animals was significantly higher than the prefrontal VIP concentrations found in the short-term animals. The finding that the prefrontal cortical VI P concentrations differed in short- and long-term animals regardless o f reserpine treatment is tentatively explained as a consequence of iso lation stress.