K. Suemaru et al., CHARACTERISTICS OF TAIL-TREMOR INDUCED BY NICOTINE IN RATS, Naunyn-Schmiedeberg's archives of pharmacology, 350(2), 1994, pp. 153-157
To characterize the tail-tremor and locomotor hyperactivity induced by
repeated nicotine administration, the effects of nicotinic, alpha-adr
energic and dopaminergic blockers were investigated in rats. Daily adm
inistration of nicotine (0.5 mg/kg, s.c.) induced tail-tremor from the
4th day, which became more marked in intensity by subsequent administ
ration. Locomotor hyperactivity was also induced by nicotine, which wa
s enhanced by dally administration. The tail-tremor and locomotor hype
ractivity induced by repeated nicotine administration were inhibited b
y mecamylamine (0.1-1 mg/kg, i.p.) but not by hexamethonium (0.5 and 1
mg/kg, i.p.). Clonidine (0.02 and 0.04 mg/kg, i.p.) and prazosin (0.5
and 1 mg/kg, i.p.) reduced tail-tremor more markedly than hyperactivi
ty. However, haloperidol (0.05-0.2 mg/kg, i.p.) and chlorpromazine (1-
5 mg/kg, i.p.) reduced hyperactivity more markedly than tail-tremor. T
hese results suggest that nicotine-induced tail-tremor and hyperactivi
ty are due to an increased susceptibility of central nicotinic recepto
rs of nicotine followed by catecholaminergic mechanisms, and that tail
-tremor may be more associated with the noradrenergic system than the
dopaminergic system.