Effects of nicotine on sniffing induced by amphetamine and apomorphine have
been tested in rats. Intraperitoneal (i.p.) administration of nicotine (0.
5 and 1 mg/kg), amphetamine (1-6 mg/kg) or apomorphine (0.1-1 mg/kg) induce
d sniffing. Nicotine (0.25-1 mg/kg) potentiates sniffing induced by ampheta
mine (1 mg/kg). Nicotine (1 mg/kg) also potentiates the response induced by
different doses (0.1-1 mg/kg) of apomorphine. Atropine induced sniffing an
d increased the response of both amphetamine and nicotine. Higher doses of
hexamethonium decreased the sniffing response induced by amphetamine and th
e response induced by combination of amphetamine and nicotine. Sulpiride re
duced the response induced by nicotine or amphetamine plus nicotine, while
SCH23390 reduced normal sniffing behaviour of the animals and sniffing indu
ced by either amphetamine or amphetamine plus nicotine. The data may indica
te that nicotinic receptor mechanism(s) may be involved in the sniffing ind
uced by dopaminergic receptor stimulation. (C) 2000 published by Elsevier S
cience B.V.