Cholecystokinin and anxiety in normal volunteers: an investigation of the anxiogenic properties of pentagastrin and reversal by the cholecystokinin receptor subtype B antagonist L-365,260.

1. Two studies were undertaken to develop a model of experimentally induced anxiety in normal volunteers based on cholecystokinin (CCK) receptor agonism/antagonism. 2. In Study 1 rapid intravenous injections of the CCK receptor subtype B (CCKB) agonist pentagastrin (0.15, 0.3 and 0.6 micrograms kg-1) were found to produce dose-related increases in subjective ratings of anxiety compared with placebo. 3. In Study 2 the effects of pre-treatment with two doses of the CCKB receptor antagonist L-365,260 (10 mg, 50 mg p.o.) on the anxiety induced by pentagastrin 0.3 micrograms kg-1 i.v. were investigated. Detailed measurements of blood pressure and pulse rate were also undertaken. Pentagastrin produced changes in blood pressure and pulse rate which had a similar time course to that observed for subjective anxiety ratings. L-365,260 reversed both the autonomic and anxiogenic effects of pentagastrin. 4. The pentagastrin model would appear to be a useful tool for investigating potential anxiolytics in normal volunteers.