Pindolol potentiates the effect of fluoxetine on hippocampal seizures in rats

Recent studies have shown that behavioral and neurochemical changes induced by selective serotonin (5-HT) reuptake inhibitors such as fluoxetine are potentiated by coadministration of a 5-HT1A receptor antagonist. The present study assessed the effects of concomitant administration of fluoxetine and a 5-HT1A receptor antagonist, pindolol, on focal hippocampal (HIP) seizures elicited by electrical stimulation in rats. A 10 mg/kg dose of fluoxetine, which was ineffective by itself, produced a significant increase in the afterdischarge threshold of HIP seizures when combined with pindolol at 10 mg/kg. The inhibitory effect of this combination was eliminated by pretreatment with parachlorophenylalanine, a depletor of brain 5-HT. These findings suggest that treatments designed to increase 5-HT neurotransmission inhibit the generation of HIP seizures. A combination of fluoxetine with a 5-HT1A receptor antagonist could thus be therapeutically useful for the treatment of depressive symptoms in patients with epilepsy.