title: K+-dependent stimulation of dopamine synthesis in striatal synaptosomes is mediated by protein kinase C.
abstract: Dopamine synthesis rate was measured in striatal synaptosomes. Removal of Na+ increased synthesis rate; this was blocked in Ca2+-free medium and by addition of the Ca2+/calmodulin inhibitor N-6-aminohexyl-5-chloro-1-naphthalenesulfonamide (W7). The increase in dopamine synthesis rate caused by the addition of the phorbol ester 12-O-tetradecanoylphorbol-13-acetate (TPA) was blocked by the protein kinase C inhibitor polymyxin B. K+-stimulated synthesis was unchanged in Ca2+-free medium or by addition of W7; it was blocked by polymyxin B. The effect of 50 mM K+ was additive with that of 8-Br cyclic AMP and of Na+ removal; the combined effect of 50 mM K+ and TPA was no greater than that of either alone. These results suggest that stimulation of dopamine synthesis in striatal synaptosomes by 50 mM K+ is mediated by protein kinase C.
authors.affiliation: University Laboratory of Physiology, Oxford, England.
authors.forename: M
authors.initials: M
authors.lastname: Chowdhury
authors.forename: M
authors.initials: M
authors.lastname: Fillenz
mesh_terms: D015124:8-Bromo Cyclic Adenosine Monophosphate / Q000494:pharmacology; D000243:Adenosine Deaminase / Q000378:metabolism; D000818:Animals; D002118:Calcium / Q000494:pharmacology; D003342:Corpus Striatum / Q000187:drug effects / Q000378:metabolism*; D004298:Dopamine / Q000096:biosynthesis*; D008297:Male; D011188:Potassium / Q000494:pharmacology*; D011493:Protein Kinase C / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains; D012964:Sodium / Q000494:pharmacology; D013449:Sulfonamides / Q000494:pharmacology; D013574:Synaptosomes / Q000187:drug effects / Q000378:metabolism*; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology
chemical_list: D013449:Sulfonamides; D015124:8-Bromo Cyclic Adenosine Monophosphate; C017967:W 7; D012964:Sodium; D011493:Protein Kinase C; D000243:Adenosine Deaminase; D013755:Tetradecanoylphorbol Acetate; D011188:Potassium; D002118:Calcium; D004298:Dopamine