Ephedrine and amphetamine induced pecking in chickens: possible indirect D-1/D-2 dopaminergic mechanism.

The involvement of dopaminergic mechanism in pecking behaviour has been suggested. In the present work, the involvement of D-1/D-2 dopamine receptors in pecking induced by ephedrine and amphetamine in chickens has been studied. Both ephedrine and amphetamine induced pecking in a dose-dependent manner. Pretreatment of animals with D-1 antagonist SCH 23390, D-2 antagonist sulpiride or reserpine decreased the pecking response induced by both drugs. Phenoxybenzamine or propranolol (alpha- or beta-adrenergic blockers, respectively) and the antimuscarinic drug atropine did not decrease the response of these drugs. The results may indicate that the pecking induced by these drugs in chickens are mediated indirectly through D-1/D-2 dopaminergic mechanisms.