Biphasic modulation of spontaneous activities of entopeduncular neurons by systemic application of apomorphine in anesthetized cats.
The responses of entopeduncular neurons to apomorphine were investigated with extracellular recording methods in anesthetized cats. Apomorphine was applied intravenously in increasing doses, which cumulatively doubled with each addition (5-640 micrograms/kg). The spontaneous firing rates of entopeduncular neurons, which were inhibited by electrical stimulation of the caudate nucleus, increased when lower doses of apomorphine (5-20 micrograms/kg) were applied. However, higher doses (40-640 micrograms/kg) produced a dose-dependent decrease in the firing rate. The results suggest that there are direct and indirect effects of systemically administered apomorphine on entopeduncular neurons which may contribute to biphasic responses in the spontaneous discharge rate.
D000200:Action Potentials / Q000187:drug effects; D000818:Animals; D001058:Apomorphine / Q000008:administration & dosage*; D001479:Basal Ganglia / Q000187:drug effects / Q000502:physiology; D002415:Cats; D004305:Dose-Response Relationship, Drug; D005917:Globus Pallidus / Q000187:drug effects* / Q000502:physiology; D007275:Injections, Intravenous; D009474:Neurons / Q000187:drug effects* / Q000502:physiology; D011930:Reaction Time / Q000187:drug effects*
D001058:Apomorphine