Role of 5-HT(2a) and 5-HT(2B/2C) receptors in the behavioral interactions between serotonin and catecholamine reuptake inhibitors.

L R McMahon, K A Cunningham

Neuropsychopharmacology : official publication of the American College of Neuropsychopharmacology 2001 Mar

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Dysfunction of monoamine neurotransmission seems to contribute to such pathopsychological states as depression, schizophrenia, and drug abuse. The present study examined the effects of the selective serotonin (5-hydroxytryptamine; 5-HT) reuptake inhibitor (SSRI) and antidepressant fluvoxamine on locomotor activity in rats following administration of the catecholamine reuptake inhibitor mazindol. Mazindol (1 mg/kg) did not alter locomotor activity; whereas, fluvoxamine (20 mg/kg) given alone induced a brief period of hypomotility. Hyperactivity was elicited in a dose-related manner when fluvoxamine (5-20 mg/kg) was combined with mazindol (1 mg/kg). The hyperactivity elicited by fluvoxamine (20 mg/kg) plus mazindol (1 mg/kg) was significantly attenuated by the 5-HT(2A) receptor antagonist M100907 (2 mg/kg) and potentiated by the 5-HT(2B/2C) receptor antagonist SB 206553 (2 mg/kg). Neither antagonist significantly altered basal activity. The hyperactivity evoked by the combination of fluvoxamine and mazindol seems to be mediated in part by 5-HT(2A) receptors; whereas, 5-HT(2B/2C) receptors may serve to limit this effect. Thus, the balance of activation between 5-HT(2A) and 5-HT(2B/2C) receptors seems to contribute to the expression of locomotor hyperactivity evoked via combination of a 5-HT and a catecholamine reuptake inhibitor. A disruption in this balance may contribute to the expression of affective disorders, schizophrenia, and drug abuse.

Citation

L R McMahon, K A Cunningham. Role of 5-HT(2a) and 5-HT(2B/2C) receptors in the behavioral interactions between serotonin and catecholamine reuptake inhibitors. Neuropsychopharmacology : official publication of the American College of Neuropsychopharmacology. 2001 Mar;24(3):319-29