TRIHEXYPHENIDYL INTERACTIONS WITH THE DOPAMINE D-1-SELECTIVE RECEPTORAGONIST SKF-82958 AND THE D-2-SELECTIVE RECEPTOR AGONIST N-0923 IN METHYL-4-PHENYL-1,2,3,6-TETRAHYDROPYRIDINE-INDUCED HEMIPARKINSONIAN MONKEYS
Ef. Domino et Ls. Ni, TRIHEXYPHENIDYL INTERACTIONS WITH THE DOPAMINE D-1-SELECTIVE RECEPTORAGONIST SKF-82958 AND THE D-2-SELECTIVE RECEPTOR AGONIST N-0923 IN METHYL-4-PHENYL-1,2,3,6-TETRAHYDROPYRIDINE-INDUCED HEMIPARKINSONIAN MONKEYS, The Journal of pharmacology and experimental therapeutics, 284(1), 1998, pp. 307-311
The effects of the antiparkinsonian agent trihexyphenidyl, a selective
M-1 muscarinic cholinergic receptor antagonist, were studied in doses
of 100, 320 and 1000 mu g/kg i.m. alone. Trihexyphenidyl was then stu
died in combination with the selective dopamine receptor D-1 agonist S
KF-82958 3-allyl-1-phenyl-2,3,4,5-tetrahydro-1H-benzazepine hydrobromi
de] and the selective D-2 agonist N-0923 (N-propyl-N-2-thienylethyl)am
ino-5-hydroxytetralin HCl] on rotational behavior in five ethyl-4-phen
yl-1,2,3,6-tetrahydropyridine-lesioned hemiparkinsonian monkeys. Given
alone, trihexyphenidyl had no effect on ipsiversive and slightly enha
nced contraversive circling. Contraversive circling produced by 74.8 a
nd 234 mu g/kg SKF-82958 i.m. was potentiated by increasing doses of t
rihexyphenidyl. On the other hand, contraversive circling produced by
10 and 32 mu g/kg N-0923 i.m. was progressively reduced with increasin
g doses of trihexyphenidyl. The results obtained indicate differential
actions on circling behavior between a selective M-1 muscarinic choli
nergic receptor antagonist and selective D-1 and D-2 receptor agonists
in the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine monkey model of h
emiparkinsonism.