Effect of the inhibition of dopamine uptake on the dopamine- and dimethyldopamine-induced-inhibition of the potassium-evoked release of [3H]acetylcholine from striatal slices.
1. Dimethyldopamine was eight times more potent than dopamine in activating the D2 receptor that inhibits the potassium-evoked release of [3H]acetylcholine from striatal slices. 2. Cocaine and mazindol produced an eight-fold shift in the concentration-response curve for dopamine, but not for dimethyldopamine. 3. The IC50 of dimethyldopamine for the inhibition of [3H]dopamine uptake was thirty times greater than that for dopamine. 4. Dopamine may be less potent than dimethyldopamine at the D2 receptor because dopamine has a higher affinity for the dopamine uptake system, resulting in its rapid removal from the vicinity of the receptor.
Farooqui
T
T
Division of Pharmacology, Ohio State University College of Pharmacy, Columbus 43210.
Wallace
R A
RA
Miller
D D
DD
Uretsky
N J
NJ
D000109:Acetylcholine / Q000378:metabolism*; D000818:Animals; D003042:Cocaine / Q000494:pharmacology; D003342:Corpus Striatum / Q000187:drug effects / Q000378:metabolism*; D004298:Dopamine / Q000031:analogs & derivatives* / Q000378:metabolism / Q000494:pharmacology; D018492:Dopamine Antagonists; D066298:In Vitro Techniques; D007700:Kinetics; D008297:Male; D008454:Mazindol / Q000494:pharmacology; D008781:Methyltyrosines / Q000494:pharmacology; D051379:Mice; D011188:Potassium / Q000037:antagonists & inhibitors* / Q000494:pharmacology; D011343:Procaine / Q000494:pharmacology; D000644:Quaternary Ammonium Compounds / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D012110:Reserpine / Q000494:pharmacology; D019805:alpha-Methyltyrosine
D018492:Dopamine Antagonists; D008781:Methyltyrosines; D000644:Quaternary Ammonium Compounds; C041923:N,N-dimethyldopamine; D011343:Procaine; D019805:alpha-Methyltyrosine; D012110:Reserpine; D008454:Mazindol; D003042:Cocaine; D000109:Acetylcholine; D011188:Potassium; D004298:Dopamine