The Effect of Acute and Chronic Ethanol on Dopamine Turnover in the Caudate Nucleus of the Rat

Abstract

It is ge nerally bel ieved that acute and chro nic e thanol (EtO H) ad ministra tion alters th e ac t ivity of ca techolam ines in the brain , however, th e specific effects of EtO H on th e dopam inergic system are disputed ( I) . Acute EtOH ad m inis tration has been vari ously reported to decrease (2 ,3), increase (4,5) , and ca use no change (6 ,7) in dopamine (DA) synthesis and turnover. Lik ewise , chronic EtO H treatmen ts have been reported to decrease (2 ,8) and increase (9, I0) DA synthesis and turnover. Many of these apparently co nflicting results are ex plained by the use of d ifferent anima l models (rat (2, 3 ,6,7, I0) , rabbi t (6), and mouse (4,5,9», different meth ods of EtO H ad min ist ration (intraperitoneal (3 ,4,6,7), oral (2,5) , and inh ala tio n (9», and no assurance of a lcoho lic dependence with ch ron ic ex posure (2, I0). Furth er , the majority of th ese stu d ies were ca rr ied out prior to th e development of a very se nsitive h igh per for mance liquid ch romatography (H PLC) tech nique which ca n detect minute amounts of DA, d ih yrox yphenylalan ine (DO PA) , and di hydroxyp henylacetic acid (DO PAC) (11 ,12). Sin ce DA receptor superse ns itivity has been fou nd in the mesoli mbic syste m of EtOH-dependent rats (1, 13) and because EtOH increases DA release in vivo (14) (indica ting th at EtO H does affect the dopaminergic syste m), we elect ed to exa mine th e effec ts o f ac ute and chron ic EtO H ad mi nistration o n th e dopaminergic syste m in th e rat ca udate nucleus .