EFFECTS OF LEAD-EXPOSURE ON LICKING AND YAWNING BEHAVIOR IN RATS

In the present study, effects of lead exposure on licking and yawning behaviour have been studied. The dopaminergic receptor agonist, apomor phine (0.15, 0.25 and 0.5 mg/kg), induced dose-dependent licking in ra ts. The maximum response was obtained with 0.5 mg/kg of the apomorphin e. Lead acetate (0.05%) exposure significantly increased apomorphine-i nduced licking. Yawning induced by the D-2 dopaminergic agonist, bromo criptine (2, 3, 4, 8 mg/kg), and the cholinergic drug, physostigmine ( 0.1 or 0.3 mg/kg), was significantly decreased by lead acetate (0.05%) exposure. It may be concluded that the behaviour induced by dopaminer gic or cholinergic agents can be affected by lead subchronic exposure.