The ontogeny of apomorphine-induced alterations of neostriatal dopamine release: effects on potassium-evoked release.
The effects of apomorphine (0.05, 0.1, and 1.0 mg/kg, s.c.) on K(+)-evoked dopamine release were studied through the use of in vivo microdialysis in the neostriatum of developing and adult rats. Fifteen-minute samples were collected from urethane-anesthetized rats 5, 10-11, 21-22, 35-36 days of age, and adults, and quantified by high performance liquid chromatography with electrochemical detection. Apomorphine attenuated K(+)-evoked dopamine release in all age groups, suggesting that the dopamine autoreceptor modulating release in the neostriatum is functional by 5 days of age. A dose-response effect of apomorphine was observed in all age groups except at 5 and 10 days of age. Absolute levels of extracellular dopamine were significantly lower at 5 and 10 days of age compared with the other ages, and the effectiveness of a high-K+ artificial cerebrospinal fluid to evoke dopamine release increased with age.
Gazzara
R A
RA
Department of Psychology, State University of New York at Binghamton 13902-6000.
Andersen
S L
SL
D000375:Aging / Q000378:metabolism*; D000704:Analysis of Variance; D000818:Animals; D001058:Apomorphine / Q000494:pharmacology*; D004298:Dopamine / Q000378:metabolism*; D008297:Male; D017551:Microdialysis; D017072:Neostriatum / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism*; D011188:Potassium / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley
D001058:Apomorphine; D011188:Potassium; D004298:Dopamine