Cocaine and automaintained responding in pigeons: rate-reducing effects and tolerance thereto with different durations of food delivery.

Pigeons were exposed to an automaintenance procedure in which 6-s key illuminations in one color (red or white) were immediately followed by 3-s food deliveries and key illuminations in the other color were followed by 9-s food deliveries. Both conditions engendered consistent responding. With both durations of food delivery, acute and chronic cocaine administrations (1.0-17.8 mg/kg) produced dose-dependent decreases in mean percent trials (key illuminations) with a response and mean total response per session. Tolerance developed to the disruptive effects of cocaine on both response measures. Food duration did not significantly affect either response measure or significantly interact with cocaine dose or drug regimen. The orderliness of the present findings, like those of a related study examining whether probability of food delivery modulated the effects of cocaine on automaintained responding [Porritt, M., Arnold, M., Poling, A., Cocaine and automaintained responding in pigeons: rate-reducing effects and tolerance thereto with different CS-US pairing probabilities. Pharmacol Biochem Behav 2007; 87:405-411.], suggests that the automaintenance procedure is a useful assay for examining tolerance to drug effects on classically-conditioned responding. Unlike the results of that study, however, the present findings are inconsistent with a behavioral momentum analysis of drug effects on such responding.

Females' participation in psychopharmacology research as authors, editors, and subjects.

This study determined the involvement of women as first authors and other authors for every article published in Experimental and Clinical Psychopharmacology, Pharmacology Biochemistry and Behavior, and Psychopharmacology in 1991, 1996, 2001, and 2006. Their involvement as editors also was determined. Women's participation as authors, but not as editors, slightly increased over time. In 2006, 43% of first authors, 38% of other authors, and 24% of editors were women. The gender of subjects was examined for the same years and journals, but could not be determined for 6% and 9% of articles employing nonhuman and human subjects, respectively. In 2006, when subjects' gender could be determined, 77% of articles involving nonhuman subjects used only males, 9% only females, and 14% both males and females. In articles using human subjects in that same year, 17% involved only males, 6% only females, and 77% both males and females. Women researchers clearly make substantial contributions to the psychopharmacology literature, but are nonetheless underrepresented as editors. Findings regarding subjects indicate that there is growing recognition of the importance of gender as a determinant of drug effects, although the vast majority of nonhuman studies continue to involve only male subjects.