Pharmacological evidence for the involvement of 1-(2-pyridinyl)-piperazine (1-PmP) in the interaction of buspirone or gepirone with noradrenergic systems.

We investigated in mice the effects of one of the principal metabolites of buspirone and gepirone, 1-(2-pyridinyl)-piperazine (1-PmP), on hypothermia and reduced locomotion induced by clonidine (0.25 and 0.06 mg/kg, respectively), tests related to brain alpha-adrenergic function. Both effects were antagonized dose dependently by 1-PmP (1-16 mg/kg i.p.). Moreover, pretreatment with proadifen (50 mg/kg) prevented the reversal by buspirone and gepirone of clonidine-induced hypothermia. This suggests that 1-PmP could be responsible for some of the apparent noradrenergic effects of buspirone and gepirone.