Topographically based search for an "ethogram" among a series of novel D-4dopamine receptor agonists and antagonists

The effects of three selective D-4 antagonists [CP-293,010, L-745,870, and Ro 61-6270] and two putative selective D-4 agonists [CP-226,269 and PD 1680 77] were compared with those of the generic D-2-like [D-2L/S, D-3, D-4] ant agonist haloperidol to identify any characteristic "ethogram," in terms of individual topographies of behavior within the natural rodent repertoire, a s evaluated using ethologically based approaches. Among the D-4 antagonists , neither L-745,870 (0.0016-1.0 mg/kg) nor Ro 61-6270 (0.2-25.0 mg/kg) infl uenced any behavior; whereas, CP-293,019 (0.2-25.0 mg/kg) induced episodes of nonstereotyped sniffing. sifting, and vacuous chewing; there were no con sistent effects on responsivity to the D-2-like agonist RU 24213. Among the putative D-4 agonists, CP-226,269 (0.2-25.0 mg/kg) failed to influence any behavior; whereas, PD 168077 (0.2-25.0 mg/kg) induced nonstereotyped shuff ling locomotion with uncoordinated movements, jerking, and yawning, which w ere insensitive to antagonism by CP-293,019, L-745,870, or haloperidol. The se findings fail to indicate any "ethogram" for selective manipulation of D -4 receptor function at the level of the interaction between motoric and ps ychological processes in sculpting behavioral topography over habituation o f exploration through to quiescence and focus attention on social, cognitiv e, or other levels of examination. (C) 2000 American College of Neuropsycho pharmacology. Published by Elsevier Science Inc.