Changes in [3H]-imipramine binding sites in relation to muricide following olfactory bulbectomy and the effect of nomifensine in brain of rats.

The effects of olfactory bulbectomy (OB) and nomifensine (NOM) on the binding of [3H]-imipramine (3H-IMP) in brain of rat were investigated. Seventy-five per cent of OB rats exhibited muricide. Acute NOM suppressed muricide in 55% and chronic NOM suppressed it in 60 80% of OB rats. In killer rats, OB increased Bmax of high-affinity (HA) and low-affinity sites (LA) in cortex (Cx) and both Bmax and KD of HA in amygdala (AMG). In rats with muricide suppressed by acute NOM 10 mg.kg-1 i.p., Bmax and KD of HA in Cx and of both HA and LA in AMG were reduced. Injection of NOM for 10 days produced further reduction of Bmax, especially of HA binding in Cx. Neither OB nor NOM exerted any significant effect on binding constants in caudate-putamen and hypothalamus. The possible relation between the changes of 3H-IMP binding, exhibition of muricide by OB rats and the antimuricidal activity of NOM are discussed.