The electrophysiology of dopamine (D2) receptors: a study of the actions of dopamine on corticostriatal transmission.
Electrophysiological recordings from the cells of the neostriatum in rats anaesthetised with halothane revealed only inhibitory actions of dopamine applied iontophoretically close to the cells. Inhibition of cortical driving seemed to have a slightly higher threshold in most cells but dopamine inhibited spontaneous action potentials, glutamate-induced responses, and cortical driving in the cells studied. Fluphenazine applied iontophoretically blocked the actions of dopamine but was itself without effect on the neuronal responses. Sulpiride, in contrast, was without effect on the spontaneous activity of the cells and was ineffective in blocking the action of applied dopamine. Sulpiride, nevertheless, increased the response to cortical stimulation though it had no action on the response to applied glutamate. These results suggest that the sub-class of dopamine receptors on the terminals of the corticostriatal pathway may be inhibitory on glutamate release and preferentially sensitive to blockade by sulpiride.
D000109:Acetylcholine / Q000494:pharmacology; D000818:Animals; D014150:Antipsychotic Agents / Q000494:pharmacology; D002540:Cerebral Cortex / Q000502:physiology*; D003342:Corpus Striatum / Q000502:physiology*; D004298:Dopamine / Q000494:pharmacology*; D004594:Electrophysiology; D005971:Glutamates / Q000494:pharmacology; D007478:Iontophoresis; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains; D011954:Receptors, Dopamine / Q000502:physiology*; D013469:Sulpiride / Q000494:pharmacology; D009435:Synaptic Transmission / Q000187:drug effects*
D014150:Antipsychotic Agents; D005971:Glutamates; D011954:Receptors, Dopamine; D013469:Sulpiride; D000109:Acetylcholine; D004298:Dopamine