Brain uptake of alpha-[14C]methyl-para-tyrosine in the rat.
The blood-brain permeabilities of L-[3H]tyrosine and the tyrosine hydroxylase (TH) inhibitor alpha-[14C]methyl-para-tyrosine ([14C]AMPT) were determined in rat striatum, a brain region rich in TH activity, and in other brain regions containing relatively little TH activity. In striatum, the unidirectional clearance rate (K1) for L-[3H]tyrosine (6.2 ml hg-1 min-1) was significantly greater than the rates for L-[14C]AMPT (2.8 ml hg-1 min-1) and D-[14C]AMPT (0.8 ml hg-1 min-1). The apparent volume of distribution (Vf) for L-[14C]AMPT in striatum (72.5 +/- 4.0 ml hg-1) did not differ from the Vf in other brain regions. The homogeneous distribution of L-[14C]AMPT in rat brain indicates that labeled AMPT is unsuitable for the study of TH in vivo by quantitative autoradiography.
Cumming
P
P
Montreal Neurological Institute, Brain Imaging Unit, Quebec, Canada.
Venkatachalam
T K
TK
Rajagopal
S
S
Diksic
M
M
Gjedde
A
A
D000818:Animals; D001345:Autoradiography; D001921:Brain / Q000033:anatomy & histology / Q000378:metabolism*; D004295:Dihydroxyphenylalanine / Q000096:biosynthesis; D008297:Male; D008781:Methyltyrosines / Q000493:pharmacokinetics*; D051381:Rats; D017208:Rats, Wistar; D013237:Stereoisomerism; D014446:Tyrosine 3-Monooxygenase / Q000037:antagonists & inhibitors*; D019805:alpha-Methyltyrosine
D008781:Methyltyrosines; D004295:Dihydroxyphenylalanine; D019805:alpha-Methyltyrosine; D014446:Tyrosine 3-Monooxygenase