Neuronal response to dopamine in rat neostriatum. A push-pull perfusion study.
In light of the sustained controversy surrounding the effects of dopamine (DA) in the striatum, this investigation sought to identify the pharmacological effects of locally infused DA on neuronal function. A push-pull perfusion technique of discrete drug application was employed, with single unit extracellular recording, in attempts to establish a clear dose-effect relationship between DA and neuronal activity. Locally perfused DA was found to modulate the discharge rate of striatal neurons over the entire test range (10(-7)-10(-10)M). Varied responses were detected, with 7% of the units exhibiting facilitation and 55% depression; 11% of these displayed biphasic excitation/inhibition. Taking everything into consideration, no strict dose-response relationship was evident for excitation and depression. However, the degree of depression appeared to be directly related to the concentration of DA which was perfused, especially when considered as a function of the initial discharge rate. Upon repeated perfusion of DA, the neuronal responsiveness progressively declined. These observations are consistent with data derived from extracellular, iontophoretic studies on the same neuronal population.
D000818:Animals; D003342:Corpus Striatum / Q000187:drug effects*; D003864:Depression, Chemical; D004298:Dopamine / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D007478:Iontophoresis; D008297:Male; D009474:Neurons / Q000187:drug effects* / Q000502:physiology; D010477:Perfusion; D051381:Rats; D011919:Rats, Inbred Strains
D004298:Dopamine