Interneurones are probably not involved in the presynaptic dopaminergic control of dopamine release in rabbit caudate nucleus.
Slices of rabbit caudate nucleus were preincubated with 3H-dopamine and then superfused. The influence of apomorphine and haloperidol on the overflow of tritium evoked by 20 mmol/l potassium was investigated in the presence and in the absence of tetrodotoxin. The potassium-evoked overflow was largely calcium-dependent and consisted mainly of 3H-dopamine. The dopamine receptor agonist apomorphine 0.01-1.0 mumol/l reduced, whereas the antagonist haloperidol 0.1 mumol/l enhanced the potassium-evoked overflow of tritium. The effects of apomorphine and haloperidol were as pronounced in the presence as in the absence of tetrodotoxin 0.3 mumol/l. It is concluded that the presynaptic dopaminergic modulation of dopamine release is not mediated by a tetrodotoxin-sensitive interneuronal pathway.
D000200:Action Potentials / Q000187:drug effects; D000818:Animals; D001058:Apomorphine / Q000494:pharmacology; D002421:Caudate Nucleus / Q000187:drug effects / Q000502:physiology*; D004298:Dopamine / Q000378:metabolism*; D006220:Haloperidol / Q000494:pharmacology; D066298:In Vitro Techniques; D007395:Interneurons / Q000502:physiology*; D011188:Potassium / Q000494:pharmacology; D011817:Rabbits; D011954:Receptors, Dopamine / Q000187:drug effects; D013779:Tetrodotoxin / Q000494:pharmacology
D011954:Receptors, Dopamine; D013779:Tetrodotoxin; D006220:Haloperidol; D001058:Apomorphine; D011188:Potassium; D004298:Dopamine