Involvement of 5‐HT1A‐ and α2‐receptors in the decreased 5‐hydroxytryptamine release and metabolism in rat suprachiasmatic nucleus after intravenous 8‐hydroxy‐2‐ (n‐dipropylamino) tetralin
Open Access
- 1 October 1986
- journal article
- research article
- Published by Wiley in British Journal of Pharmacology
- Vol. 89 (2), 277-286
- https://doi.org/10.1111/j.1476-5381.1986.tb10257.x
Abstract
1 The 5-hydroxytryptamine1A-receptor agonist 8-hydroxy-2-(n-dipropylamino) tetralin (8-OH-DPAT, 0.1 mg kg−1 i.v.) decreased the height of the extracellular 5-hydroxyindoleacetic acid (5-HIAA) oxidation peak recorded in the suprachiasmatic nucleus (SCN) of the anaesthetized rat by use of differential pulse voltammetry. 2 The decrease in extracellular 5-HIAA produced by 8-OH-DPAT could be partially attenuated by prior administration of the non-selective 5-HT receptor antagonist methiothepin (1 mg kg−1 i.v.). The 5-HT2-receptor antagonist ritanserin (0.2 mg kg−1 i.v.) did not appear to block the effects of 8-OH-DPAT. 3 The selective ligand for 5-HT1A recognition sites TVX Q 7821 (isapirone, 1 mg kg−1 i.v.) decreased the extracellular level of 5-HIAA in the SCN but to a lesser extent than 8-OH-DPAT. The response to 8-OH-DPAT was attenuated by prior administration of TVX Q 7821 to a level suggesting that TVX Q 7821 had blocked the effect of intravenous 8-OH-DPAT. 4 Idazoxan (0.2 mg kg−1 i.v.) an α2-adrenoceptor antagonist, completely blocked the effect of 8-OH-DPAT on the 5-HIAA oxidation peak recorded in the SCN, whilst having no effect on the 5-HIAA oxidation peak when given alone. 5 At a dose of 0.5 mg kg−1 i.v. idazoxan induced a 120% increase in the height of the indole oxidation peak, suggesting that 5-HT release and metabolism in the rat SCN may be influenced by tonic adrenergic inputs. 6 The data in this paper suggest that 5-HT1A- and α2-receptors are involved in the effects of i.v. administered 8-OH-DPAT on 5-HT release and metabolism in the SCN in vivo.This publication has 28 references indexed in Scilit:
- Anatomical and physiological characteristics of vestibular neurons mediating the horizontal vestibulo‐ocular reflex of the squirrel monkeyJournal of Comparative Neurology, 1987
- Differential selectivities of RU 24969 and 8-OH-DPAT for the purported 5-HT1A and 5-HT1B binding sites. Correlation between 5-HT1A affinity and hypotensive activityEuropean Journal of Pharmacology, 1985
- The putative 5-HT1 receptor agonist, RU 24969, inhibits the efflux of 5-hydroxytryptamine from rat frontal cortex slices by stimulation of the 5-HT autoreceptorJournal of Pharmacy and Pharmacology, 1985
- [3H]5‐Hydroxytryptamine Binding Sites: Species and Tissue VariationJournal of Neurochemistry, 1984
- Voltammetric measurements of 5-hydroxyindole compounds in the suprachiasmatic nuclei: Circadian fluctuationsBrain Research, 1983
- 8-hydroxy-2-(di-n-propylamino)tetralin, 8-OH-DPAT, a potent and selective simplified ergot congener with central 5-HT-receptor stimulating activityJournal of Neural Transmission, 1982
- Comparison of the pharmacological characteristics of 5 HT1 and 5 HT2 binding sites with those of serotonin autoreceptors which modulate serotonin releaseNaunyn-Schmiedebergs Archiv für experimentelle Pathologie und Pharmakologie, 1982
- Receptor binding profile of R 41 468, A novel antagonist at 5-HT2 receptorsLife Sciences, 1981
- Discrimination of Multiple [3H]5‐Hydroxytryptamine Binding Sites by the Neuroleptic Spiperone in Rat BrainJournal of Neurochemistry, 1981
- Normal pulse polarography with carbon fiber electrodes for in vitro and in vivo determination of catecholaminesAnalytical Chemistry, 1979