An ethologically based, stimulus and gender-sensitive nonhuman primate model for anxiety.

1. Adult male and female squirrel monkeys were tested for behavioral responses to 5 min. social separation (alone in test room) followed by 30-sec. exposure to 2 humans wearing a leather capture glove. 2. Trials were preceded by intramuscular injection of an anticholinergic drug, benactyzine hydrochloride, in doses of 0.0, 0.6, 1.0, 2.0, and 3.0 mg/kg. 3. Measured behaviors were number and type of vocalization and locomotor activity (duration in sec) in each of the two testing conditions. 4. A dose-response relationship for bark/yap vocalizations during the 30-sec trials was established, with 1.0 mg/kg being the most effective dose. 5. Males and females differed in the number of barks/yaps produced during 30-sec. trials at every drug dose. 6. The present testing paradigm provides the basis for efficiently determining the extent of gender differences in dose/response relationships for drugs of possible therapeutic value in the treatment of anxiety-related behavioral disorders.