[The measurement of tyrosine hydroxylase activity in the brain of conscious rats].
OBJECTIVE
To set the measuring method of tyrosine hydroxylase activity in the brain of conscious rats.


METHODS
By using microdialysis and High Performance Liquid Chromatography-Electrochemical Detector system, the 3, 4-dihydrioxphenylalanine (DOPA) formation in the striatum of 6-hydroxdopamine-pretreated rats during infusion of an L-aromatic amino-acid decarboxylase inhibitor (NSD1015) was monitored.


RESULTS
The absence of DOPA in dialysates of 6-hydroxdopamine-pretreated rats, the measurable DOPA and the steady decreasing of 3,4-dihydroxyphenylacetic acid(DOPAC) during infusion of NSD1015 and the disappearance of DOPA after administration of alpha-methyl-rho-tyrosine indicated that the dialyzed DOPA was derived from dopaminergic nerve terminals. After intraperitoneal administration of dopamine receptor agonist apomorphine the DOPA output was deseased. After intraperitoneal administration of dopamine recepter antagonist haloperidol, the DOPA output was increased. The study showed that twenty-four hours ofter implantation of the probe with infusion of 0.01 mmol.L-1 NSD1015, the DOPA level in the striatum of 6-hydroxdopamine-pretreated rats was 0.39 +/- 0.12 pmol/min (X +/- S, n = 5).


CONCLUSIONS
The DOPA concentration in striatal dialysates could be considered as an index of tyrosion hydroxlase activity during infusion of 0.01 mM NSD1015. The method in vivo to monitor tyrosine hydroxlase activity in the brain is reliable.
Wang
Wei
W
Department of Geriatrics, Xiyuan Hospital, China Academy of TCM, Beijing 100091, China.
Zhao
De-zhong
DZ
Wang
Wei-xia
WX
Sun
Bin-hui
BH
D000818:Animals; D001058:Apomorphine / Q000494:pharmacology; D001921:Brain / Q000201:enzymology*; D004295:Dihydroxyphenylalanine / Q000378:metabolism; D018491:Dopamine Agonists / Q000494:pharmacology; D018492:Dopamine Antagonists / Q000494:pharmacology; D005260:Female; D006220:Haloperidol / Q000494:pharmacology; D008297:Male; D017551:Microdialysis; D051381:Rats; D017207:Rats, Sprague-Dawley; D014446:Tyrosine 3-Monooxygenase / Q000378:metabolism*
D018491:Dopamine Agonists; D018492:Dopamine Antagonists; D004295:Dihydroxyphenylalanine; D014446:Tyrosine 3-Monooxygenase; D006220:Haloperidol; D001058:Apomorphine