S. Nakamura et al., ENDOGENOUSLY RELEASED DOPA IS PROBABLY RELEVANT TO NICOTINE-INDUCED INCREASES IN LOCOMOTOR ACTIVITIES OF RATS, Japanese Journal of Pharmacology, 62(1), 1993, pp. 107-110
The relevance of endogenously released DOPA to the (+/-)-nicotine-indu
ced increase in locomotor activities was explored in rats. This increa
se was dose (0. 1 - 1.0 mg/kg, s. c.)-dependent, stereoselective and m
ecamylamine (1.0 mg/kg, s.c.)-sensitive, but was not antagonized by L-
dopa methyl ester (200 mug, i.v.t.), a competitive L-dopa antagonist.
Then, by microdialysis, low doses of alpha-methyl-p-tyrosine (alpha-MP
T, i.p.) at 1 - 10 mg/kg, were tested to find a dose that selectively
inhibits the basal DOPA release in the striata: the release was consis
tently inhibited by 3 mg/kg without any tendency to inhibit the basal
dopamine release. Pretreatment with this dose did inhibit the nicotine
-induced increases in locomotor activities. This suggests that endogen
ously released DOPA is in part relevant to the nicotine-induced behavi
or in rats.