K. Suemaru et al., INVOLVEMENT OF THE CENTRAL CATECHOLAMINERGIC SYSTEM IN NICOTINE-INDUCED TAIL-TREMOR IN RATS, Acta medica Okayama, 52(1), 1998, pp. 49-53
The effect of 6-hydroxydopamine on repeated nicotine-induced tail-trem
or was investigated in rats. Tail-tremor induced by nicotine (0.5 mg/k
g/day, subcutaneously) became more pronounced in intensity with daily
administration for 9 days. Rats pretreated with 6-hydroxydopamine (250
mu g, intracerebroventricularly) showed almost the maximum degree of
tail-tremor during the whole experimental period, However, in rats pre
treated with 6-hydroxydopamine plus desipramine, enhancement of tail-t
remor was slight in the beginning but increased with the daily nicotin
e administration. Fourteen-day administration of nicotine did not resu
lt in significant changes in noradrenaline and dopamine levels in the
cortex, hypothalamus, striatum and nucleus accumbens. These results su
ggest that nicotine-induced tail-tremor is associated with the superse
nsitivity of postsynaptic catecholaminergic receptors in the central n
ervous system, and that the noradrenergic system may be more important
than the dopaminergic system in this phenomenon.