Acute administration of cocaine regulates the phosphorylation of serine-19, -31 and -40 in tyrosine hydroxylase.
Acute cocaine can inhibit catecholamine biosynthesis by regulating the enzymatic activity of tyrosine hydroxylase via alterations in the phosphorylation state of the enzyme. The mechanisms underlying acute cocaine-dependent regulation of tyrosine hydroxylase phosphorylation have not been determined. In this study, 0, 15 or 30 mg/kg cocaine was administered intraperitoneally to rats and the phosphorylation state of tyrosine hydroxylase in the brain was examined using antibodies specific for the phosphorylated forms of serine-19, -31 and -40 in tyrosine hydroxylase. In the caudate and nucleus accumbens, cocaine dose-dependently decreased the levels of phosphorylated serine-19, -31 and -40. In the ventral tegmental area, the levels of phosphorylated serine-19, but not serine-31 and -40, were decreased by 15 and 30 mg/kg cocaine. In the amygdala, the levels of phosphorylated serine-19, but not serine-31 or -40, were decreased. The functional effects of these alterations in phosphorylation state were assessed by measuring tyrosine hydroxylase activity in vivo (accumulation of DOPA after administration of the decarboxylase inhibitor NSD-1015). Acute administration of 30 mg/kg cocaine significantly decreased l-DOPA production in caudate and accumbens but not in amygdala. These data suggest that the phosphorylation of serine-31 or -40, but not serine-19, is involved in the regulation of tyrosine hydroxylase activity by acute cocaine.
Jedynak
Jakub P
JP
Behavioral Neuroscience Branch, The National Institute on Drug Abuse, Intramural Research Program, Baltimore, Maryland 21224, USA.
Ali
Syed F
SF
Haycock
John W
JW
Hope
Bruce T
BT
D000679:Amygdala / Q000187:drug effects / Q000378:metabolism; D000818:Animals; D065105:Aromatic Amino Acid Decarboxylase Inhibitors; D001665:Binding Sites / Q000187:drug effects; D015153:Blotting, Western; D001921:Brain / Q000187:drug effects* / Q000378:metabolism; D002421:Caudate Nucleus / Q000187:drug effects / Q000378:metabolism; D003042:Cocaine / Q000008:administration & dosage*; D004295:Dihydroxyphenylalanine / Q000032:analysis / Q000096:biosynthesis; D004305:Dose-Response Relationship, Drug; D004789:Enzyme Activation / Q000187:drug effects; D004791:Enzyme Inhibitors / Q000494:pharmacology; D007274:Injections, Intraperitoneal; D008297:Male; D009714:Nucleus Accumbens / Q000187:drug effects / Q000378:metabolism; D010766:Phosphorylation / Q000187:drug effects; D051381:Rats; D017207:Rats, Sprague-Dawley; D012694:Serine / Q000378:metabolism*; D014446:Tyrosine 3-Monooxygenase / Q000187:drug effects* / Q000378:metabolism*; D017557:Ventral Tegmental Area / Q000187:drug effects / Q000378:metabolism
D065105:Aromatic Amino Acid Decarboxylase Inhibitors; D004791:Enzyme Inhibitors; D012694:Serine; D004295:Dihydroxyphenylalanine; D014446:Tyrosine 3-Monooxygenase; D003042:Cocaine