Time schedule of apomorphine administration determines the degree of globus pallidus excitation

Abstract

Intravenous administration of a single 320 μg/kg bolus of apomorphine signicantly increased the unit activity of rat globus pallidus neurons. Significantly attenuated responses to apomorphine were observed when 320 μg/kg apomorphine was administered i.v. in divided doses (5, 35, 280 μg/kg) 3–5 min apart of when 320 μgg/kg apomorphine was given i.v. 8 min after nonexcitatory ‘priming’ dose (20 μg/kg i.v.) of apomorphine. These results suggest that the expression and magnitude of apomorphine-induced excitation of pallidal neurons is influenced by the time schedule of drug administration.