Effects of the specific serotonin reuptake inhibitor, citalopram, upon local cerebral blood flow and glucose utilisation in the rat

The effects of the potent selective 5-HT reuptake blocking agent, citalopram (10 mg/kg, i.v.), on local cerebral blood flow (lCBF) and local cerebral metabolic rate of glucose (lCMRglu) were measured using [ 14 C ]iodoantipyrine (IAP) and [ 14 C ]2-deoxyglucose (2-DG) autoradiography, respectively. Significant decreases in lCBF were observed in nine of the 27 brain areas analysed, with significant decreases in lCMRglu observed in 17 areas. While decreases in blood flow were observed, it cannot be concluded that these were in fact the result of a direct action of 5-HT upon serotonergic receptors in cerebrovascular smooth muscle, since the dynamic relationship between flow and metabolism remains largely intact. The reductions in lCBF may be explained entirely by the secondary effects of depressed cerebral metabolic demand induced by citalopram which would, once again, question the role of specifically perivascular serotonergic nerve activity in the tonic control of cerebral blood flow.