The effects of Adrenergic agents on the dopaminergic-induced sniffing

  There is evidence indicating that adrenoceptor mechanisms may influence some of the behaviors in rat. However the role of adrenoceptor agents on sniffing has not been identified. In the present study, the influence of adrenoceptor agents on sniffing induced by apomorphine and amphetamine has been investigated. Male Albino rats, weighing 150-250 g were used for all experiments. The behavior was measured based on the method we used previously. Sniffing was scored every 15 sec according to the following scale: 0=absent, 1=sniffing. At each 60 min period, the sniffing score ± SEM of at least 9 rats was scored Score 0 indicates no sniffing, score 240 indicated maximum sniffing. Effects of adrenergic agonists and antagonists on sniffing induced by amphetamine and apomorphine have been tested in rats. Intraperitoneal (IP) administration of different doses of amphetamine (2-8 mg/kg) induced a dose-related sniffing. IP administration of apomorphine (0.5 mg/kg) also induced sniffing. Different doses of clonidine, phenylephrine and prazocin decreased sniffing induced by both amphetamine and apomorphine. Yohimbine reduced inhibitory influence of clonidine on amphetamine- and apomorphine-induced sniffing. However the response of phenylephrine was not altered by prazocin pretreatment. It is concluded that α2 adrenoceptor stimulation is able to reduce sniffing induced by dopaminergic system.