Intravenous self-administration of cathinone by rats

Cathinone is the principal psychoactive constituent in leaves of the khat shrub. In some parts of the world, khat leaves are commonly chewed for their stimulant effects. While it has been demonstrated that rhesus monkeys will self-administer cathinone, there has been no demonstration of cathinone self-administration in rats. Two experiments were therefore conducted on rats fitted with intravenous catheters. On an FR 1 reinforcement schedule, the dose response curve for cathinone was shifted to the left of that for cocaine by a factor of approximately two. Within the sessions, cocaine infusions tended to be spaced evenly, whereas cathinone infusions were generally more frequent in the early portions of the session than later. In a second experiment, pretreatment with the dopamine D1-type receptor antagonist SCH 23390, at 10 mg/kg, significantly increased the number of infusions obtained. Pretreatment with the D2-type receptor antagonist spiperone caused only a slight, non-significant increase in cathinone self-administration. These results demonstrate that cathinone is a potent reinforcer in rats and suggest a role for D1-type dopamine receptors in mediating its reinforcing effects.