Responses of central neurones to piribedil and 2-bromo-alpha-ergocryptine: comparison with dopamine and apomorphine.
The effects of two putative dopamine receptor agonists, piribedil and 2-bromo-alpha-ergocryptine were studied by means of microiontophoresis. Their effects were compared with those of dopamine and apomorphine on neurones of the frontal cortex and of the caudate nucleus both of which are rich in dopaminergic terminals. Piribedil and S. 584, its dihydroxyphenyl derivative, displayed a potent dopamine-like inhibition in both these areas. 2-Bromo-alpha-ergocryptine exerted significant inhibition on cortical neurones which were spontaneously active but only weak or negligible inhibition on cortical and caudate glutamate-driven units. These observations raise the possibilities that 2-bromo-alpha-ergocryptine (1) mediates its inhibitory effect via a predominant presynaptic action; (2) acts preferentially on cortical neurones.
D000818:Animals; D001058:Apomorphine / Q000494:pharmacology*; D001921:Brain / Q000166:cytology / Q000187:drug effects*; D001971:Bromocriptine / Q000494:pharmacology*; D002415:Cats; D002421:Caudate Nucleus / Q000166:cytology / Q000187:drug effects; D002540:Cerebral Cortex / Q000166:cytology / Q000187:drug effects; D004298:Dopamine / Q000494:pharmacology*; D005260:Female; D008297:Male; D009474:Neurons / Q000187:drug effects*; D010879:Piperazines / Q000494:pharmacology*; D010891:Piribedil / Q000494:pharmacology*; D051381:Rats; D013997:Time Factors
D010879:Piperazines; D001971:Bromocriptine; D010891:Piribedil; D001058:Apomorphine; D004298:Dopamine