P.1.g.072 Benzodiazepine acts on the defense response, but not on the aversive information processing, elicited by the inferior colliculus of rats

Abstract

have counteractive effects on downstream signalling molecules, including glycogen synthase kinase 3 and n-methyl-D-aspartate receptors. Functional interaction between 5-HT1A and 5-HT2A receptors has been suggested, but its molecular basis is not clarified. The aim of the current study was to gain insight in downstream signalling molecules involved in the interaction between 5-HT1A and 5-HT2A receptors. Methods: Rat primary cortical neurons derived from 18-dayold Sprague-Dawley rat embryos cerebral cortices and lymphoblastoid cell lines derived from lymphocytes of three healthy control individuals were used as two independent cell culture models. 5-HT1A and 5-HT2A receptors expression levels were determined with quantitative real-time polymerase chain reaction and western blot. An antibody array allowing the simultaneous detection of 18 well-characterized intracellular signalling molecules when phosphorylated or cleaved was used for screening the effect of 5-HT1A and 5-HT2A receptors agonists on intracellular signalling molecules in rat cortical neurons. Western blot was used for validation of intracellular signalling molecules involved in 5-HT1A and 5-HT2A receptors interaction in both cortical neurons and lymphoblastoid cell lines. Results: We confirmed 5-HT1A and 5-HT2A receptors mRNA and protein expression in rat cortical neurons. The antibody array results of 15min treatment with vehicle, 1 mM of the 5-HT2A receptor agonist 2,5-dimethoxy-4-iodoamphetamine hydrochloride (DOI), 1mM of the 5-HT1A receptor agonist 8-hydroxy-2(dipropylamino)tetralin hydrobromide (8-OH-DPAT), or 15min pre-treatment with 1mM 8-OH-DPAT followed by 15min treatment with 1mM DOI suggested phosphorylation of the extracellular signal-regulated kinase (Erk1/2) at Thr202/Tyr204 and phosphorylation of the stress-activated protein kinase/Jun-aminoterminal kinase (SAPK/JNK) at Thr183/Tyr185 as potential intracellular signalling molecules modifications involved in the crosstalk between 5-HT1A and 5-HT2A receptors agonists after shortterm treatment. The antibody array results of 24 h treatment with vehicle, 1mM of the 5-HT2A receptor agonist DOI, 1 mM of the 5-HT1A receptor agonist 8-OH-DPAT, or 15min pre-treatment with 1mM 8-OH-DPAT followed by 24 h treatment with 1mMDOI suggested phosphorylation of protein kinase B (Akt) at Ser473 as an intracellular signalling modification that may be involved in the cross-talk between 5-HT1A and 5-HT2A receptors agonists after longer term treatment. We are currently carrying out validation of the antibody array results with western blot in rat cortical neurons and lymphoblastoid cell lines. Conclusions: Our results suggest that intracellular signalling molecules may be involved in the cross-talk between 5-HT1A and 5-HT2A receptors agonists in cell culture models. The characterization of signalling molecules implicated in 5-HT1A and 5-HT2A receptors cross-talk may help to better understand the dysfunction of these receptor subtypes in psychiatric disorders and possibly even to identify potential new therapeutic targets.