Circling behaviour in rats with unilateral lesions of the nigrostriatum induced by 6-hydroxydopamine: changes induced by oral administration of cytidine-5'-diphosphocholine.
A unilateral administration of 6-hydroxydopamine into the nigrostriatal system of the rat was responsible for ipsiversive circling behaviour in response to administration and, in time, of contraversive circling behaviour in response to L-DOPA and apomorphine. This contraversive circling behaviour appears to be mediated by the development, on the lesioned side, of supersensitivity of postsynaptic dopamine receptors. Subchronic treatment with cytidine-5'-diphosphocholine (p.o.) by itself was devoid of behavioural effects. The CDP-choline did not modify the apomorphine-induced stimulant effect but potentiated the circling behaviour produced by L-DOPA and amphetamine. The data show that the effects of CDP-choline were mediated by a presynaptic mechanism: the potentiation of the effects of L-DOPA cannot be explained by an activation of tyrosine hydroxylase, but seems to be related to an improvement of release of newly synthesized dopamine from exogenous L-DOPA.
D000284:Administration, Oral; D000661:Amphetamine / Q000494:pharmacology; D000818:Animals; D001058:Apomorphine / Q000494:pharmacology; D001522:Behavior, Animal / Q000187:drug effects / Q000502:physiology*; D002794:Choline / Q000031:analogs & derivatives*; D003342:Corpus Striatum / Q000187:drug effects / Q000473:pathology / Q000502:physiology*; D003566:Cytidine Diphosphate Choline / Q000494:pharmacology*; D006892:Hydroxydopamines / Q000494:pharmacology*; D007980:Levodopa / Q000494:pharmacology; D008297:Male; D016627:Oxidopamine; D051381:Rats; D011919:Rats, Inbred Strains; D013378:Substantia Nigra / Q000187:drug effects / Q000473:pathology / Q000502:physiology*
D006892:Hydroxydopamines; D007980:Levodopa; D003566:Cytidine Diphosphate Choline; D016627:Oxidopamine; D000661:Amphetamine; D001058:Apomorphine; D002794:Choline