Investigations into the relationship between the dopaminergic system and ascorbic acid in rat striatum.
Levels of dopamine (DA), 3,4-dihydroxyphenylacetic acid (DOPAC), ascorbic acid (AA) and dehydroascorbic acid (DHAA) were determined by HPLC in the striatum of male Wistar rats after single or repeated injections of apomorphine (1 mg/kg/day s.c.) and/or haloperidol (1 mg/kg/day i.p.), and 24 h after the last drug administration. Apomorphine significantly reduced the DOPAC/DA ratio and increased the DHAA/AA ratio; these ratio changes were significantly correlated (r = -0.9969, P less than 0.0005). Haloperidol greatly increased the DOPAC/DA ratio; the DHAA/AA ratio was also slightly increased, but there was no significant correlation. When apomorphine was associated with haloperidol, the resulting DOPAC/DA ratio was significantly lower than after haloperidol alone; the DHAA/AA ratio was also significantly reduced in contrast to the effect of apomorphine alone. It is concluded that a non-selective DA receptor activation mediates, in a correlated way, both the inhibition of DA turnover and the increase of AA oxidation in the rat striatum.
Desole
M S
MS
Institute of Pharmacology, University of Sassari, Italy.
Miele
M
M
Enrico
P
P
Esposito
G
G
Fresu
L
L
De Natale
G
G
Miele
E
E
D000818:Animals; D001058:Apomorphine / Q000494:pharmacology; D001205:Ascorbic Acid / Q000378:metabolism*; D003342:Corpus Striatum / Q000378:metabolism*; D004298:Dopamine / Q000378:metabolism*; D018492:Dopamine Antagonists; D006220:Haloperidol / Q000494:pharmacology; D066298:In Vitro Techniques; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains
D018492:Dopamine Antagonists; D006220:Haloperidol; D001058:Apomorphine; D001205:Ascorbic Acid; D004298:Dopamine