THE ANTAGONISM OF IPSAPIRONE INDUCED BIOBEHAVIORAL RESPONSES BY + - PINDOLOL IN HIGH AND LOW IMPULSIVES/

The present study was conducted to investigate whether +/- pindolol an tagonizes ipsapirone induced biobehavioral changes in a personality de pendent way. Our previous work demonstrated that high impulsives show higher immune cell responses than low impulsive subjects upon treatmen t with ipsapirone. A total number of 80 healthy male volunteers receiv ed placebo (N = 20) or 10mg ipsapirone (N = 20), 30mg +/- pindolol (N 20), or a combination of 30mg +/- pindolol and 10mg ipsapirone (N = 20 ). Each group consisted of 10 low and 10 high impulsive subjects. Sinc e 5-HT related drugs induce thermoregulatory responses, the study took place in a climate chamber with a constant ambient temperature. Blood samples (for measurement of CD4+ cell counts) were drawn from an indw elling catheter invisibly for the subjects. The results clearly demons trate that the ipsapirone induced decreases in body temperature and nu mber of peripheral CD4+ cells are more pronounced in high impulsives. +/- Pindolol antagonizes the thermoregulatory and CD4+ cell responses. The results are discussed with respect to mechanisms of alteration in 5-HT function related to impulsivity.