TY - JOUR T1 - Alterations of central serotonin and dopamine turnover in rats treated with ipsapirone and other 5-hydroxytryptamine1A agonists with potential anxiolytic properties. JF - Journal of Pharmacology and Experimental Therapeutics JO - J Pharmacol Exp Ther SP - 745 LP - 752 VL - 246 IS - 2 AU - M Hamon AU - C M Fattaccini AU - J Adrien AU - M C Gallissot AU - P Martin AU - H Gozlan Y1 - 1988/08/01 UR - http://jpet.aspetjournals.org/content/246/2/745.abstract N2 - Measurements of tissue levels of monoamines and their metabolites, and of the rates of 5-hydroxytryptophan and dihydroxy-phenylalanine accumulation after blockade of aromatic amino acid decarboxylase by benserazid indicated that ipsapirone (1-10 mg/kg i.p.) decreased 5-hydroxytryptamine (5-HT) turnover and accelerated dopamine (DA) turnover in various brain regions. The reduced 5-HT turnover probably resulted from the stimulation of 5-HT1A autoreceptors within the anterior raphe nuclei as in vitro tests [( 3H]-8-hydroxy-2-[di-n-propylamino]tetralin binding and adenylate cyclase assays) demonstrated that ipsapirone was a 5-HT1A agonist almost as potent as 8-OH-DPAT, and the same decrease in 5-hydroxytryptophan accumulation could be induced by the i.p. (5 mg/kg) or intraraphe (1 microgram) injection of ipsapirone. Ipsapirone-induced acceleration of DA turnover persisted after the selective degeneration of serotoninergic neurons by intraraphe 5,7-dihydroxytryptamine infusion, and could be reproduced by i.p. administration of other 5-HT1A agonists like buspirone and gepirone, but not 8-OH-DPAT. These results demonstrate that ipsapirone-induced acceleration of DA turnover did not result from the stimulation of 5-HT1A (auto)receptors, but involved additional target(s) of the drug. The possible participation of dopaminergic systems in the "anxiolytic" properties of ipsapirone should deserve further investigations. ER -