title: Influence of thyroid hormone on 5-HT(1A) and 5-HT(2A) receptor-mediated regulation of hippocampal BDNF mRNA expression.
abstract: The aim of the present study was to determine the influence of thyroid hormone, T3, on the regulation of hippocampal BDNF expression by 5-HT receptor agonists. Chronic T3 administration prior to treatment with the 5-HT(1A) agonist, 8-OH-DPAT, significantly decreased BDNF mRNA in the dentate gyrus region of the hippocampus. Administration of 8-OH-DPAT did not alter hippocampal BDNF mRNA expression in naive, euthyroid rats. Pretreatment with the 5-HT(1A) antagonist, WAY 100635, completely blocked the 8-OH-DPAT-induced down-regulation of BDNF mRNA in chronic T3-treated rats. Acute T3 administration prior to 8-OH-DPAT treatment led to a small, but significant, decrease in hippocampal dentate gyrus BDNF mRNA. Acute or chronic administration of T3 did not alter the decrease in hippocampal BDNF mRNA induced by the 5-HT(2A/2C) receptor agonist, DOI. The influence of 8-OH-DPAT and DOI on hippocampal BDNF mRNA was also unaltered in rats rendered hypothyroid by propylthiouracil administration. Chronic T3 treatment or hypothyroidism did not influence the basal expression of hippocampal BDNF mRNA. The affinity and density of 5-HT(1A) receptors, and the hippocampal expression of 5-HT(1A) mRNA were also not influenced by chronic T3 treatment. The results of this study clearly demonstrate a powerful interaction between thyroid hormone and the 5-HT(1A) receptor in the regulation of hippocampal BDNF expression. Crosstalk between signal transduction cascades influenced by T3 and 5-HT(1A) receptors may mediate the synergistic effects of these systems on hippocampal BDNF expression.
authors.affiliation: University Department of Clinical Pharmacology, University of Oxford, Radcliffe Infirmary, Woodstock Road, OX2 6HE, Oxford, UK. vvaidya@tifr.res.in
authors.forename: V A
authors.initials: VA
authors.lastname: Vaidya
authors.forename: M E
authors.initials: ME
authors.lastname: Castro
authors.forename: Q
authors.initials: Q
authors.lastname: Pei
authors.forename: M E
authors.initials: ME
authors.lastname: Sprakes
authors.forename: D G
authors.initials: DG
authors.lastname: Grahame-Smith
mesh_terms: D017371:8-Hydroxy-2-(di-n-propylamino)tetralin / Q000494:pharmacology; D000818:Animals; D013956:Antithyroid Agents / Q000494:pharmacology; D001345:Autoradiography; D019208:Brain-Derived Neurotrophic Factor / Q000096:biosynthesis*; D006624:Hippocampus / Q000187:drug effects / Q000378:metabolism*; D017403:In Situ Hybridization; D008297:Male; D011441:Propylthiouracil / Q000494:pharmacology; D012333:RNA, Messenger / Q000096:biosynthesis* / Q000235:genetics; D051381:Rats; D017207:Rats, Sprague-Dawley; D044402:Receptor, Serotonin, 5-HT2A; D011985:Receptors, Serotonin / Q000187:drug effects*; D044263:Receptors, Serotonin, 5-HT1; D017366:Serotonin Receptor Agonists / Q000494:pharmacology; D013963:Thyroid Hormones / Q000494:pharmacology*; D014284:Triiodothyronine / Q000097:blood / Q000494:pharmacology
chemical_list: D013956:Antithyroid Agents; D019208:Brain-Derived Neurotrophic Factor; D012333:RNA, Messenger; D044402:Receptor, Serotonin, 5-HT2A; D011985:Receptors, Serotonin; D044263:Receptors, Serotonin, 5-HT1; D017366:Serotonin Receptor Agonists; D013963:Thyroid Hormones; D014284:Triiodothyronine; D011441:Propylthiouracil; D017371:8-Hydroxy-2-(di-n-propylamino)tetralin