FAILURE OF INTRAVENOUS PENTAGASTRIN CHALLENGE TO INDUCE PANIC-LIKE EFFECTS IN RHESUS-MONKEYS

We examined the ability of intravenous (i.v.) challenge with pentagast rin to induce behavioural and cardiovascular effects consistent with p anic attack in conscious rhesus monkeys. For behavioural evaluation, 4 naive male rhesus monkeys familiar with minimal manual restraint nece ssary for drug administration received a rapid i.v. bolus of pentagast rin (4, 8 or 16 mug/kg) or water on four separate occasions according to a randomised cross-over design. Behaviour was rated by a blind obse rver continuously during, and for the first 5 min immediately followin g i.v. injections while the monkey sat on the handler's lap, and then for a further 25 min in an individual observation cage. In separate ex periments, the ability of pentagastrin to alter cardiovascular paramet ers which may accompany panic or anxiety (elevated heart rate and bloo d pressure) was explored. For cardiovascular studies, 8 male or female rhesus monkeys with femoral artery catheters were chair restrained an d received a bolus injection of pentagastrin (4, 8 or 16 mug/kg) or sa line into the saphenous vein at 30 min intervals. Blood pressure and h eart rate were monitored continuously using a Statham Gould pressure t ransducer. Pentagastrin induced no consistent behavioural or cardiovas cular changes. Similar pilot studies using CCK4 also failed to reveal such effects. We conclude that CCK-induced panic-like effects may not be demonstrable following challenge with pentagastrin under laboratory conditions in rhesus monkeys.