Abstract
We have determined the pharmacological characteristics of the rat 5-ht6 receptor stably expressed in CHO cells. Moreover, using RT-PCR experiments the in vivo expression of the gene encoding this receptor was studied in rat at various embryonic days (ED) starting from ED10 to birth (PN0) and at post-natal days (PN) up to PN36. The pharmacological analysis of the [3H]5-HT binding in stably transfected CHO cells expressing rat 5-ht6 receptors revealed the presence of a single class of high affinity saturable binding sites for 5-HT corresponding to an affinity constant: Kd = 27.2±3.4 nM. This receptor also exhibited a high affinity for a number of typical and atypical antipsychotics, tricyclic antidepressant drugs and ergot alkaloïds. In stably transfected CHO cells, serotonin elicited a potent stimulation of adenylyl cyclase activity which was blocked by antipsychotic and antidepressant drugs. These results confirm the hypothesis that 5-ht6 receptors may correspond to an important target for atypical antipsychotics and reveal an original pharmacological profile for this receptor. The study of the ontogeny of the 5-ht6 mRNA in rat develo** brain showed that 5-ht6 mRNA were first detectable with a high level on ED12, slighly decreased up to ED17 and then remained stable at high level until the adult age. The ontogenetic pattern of 5-ht6 mRNA expression appeared to correlate with the occurence of the first cell bodies of serotonergic neurons; the early expression of 5-ht6 mRNA and the fact that this receptor is positively coupled to the production of cAMP may suggest a role for 5-ht6 receptor in the early growth process involving the serotonergic system.
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Received: 31 October 1997 / Accepted: 24 January 1998
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Grimaldi, B., Bonnin, A., Fillion, MP. et al. Characterization of 5-ht6 receptor and expression of 5-ht6 mRNA in the rat brain during ontogenetic development. Naunyn-Schmiedeberg's Arch Pharmacol 357, 393–400 (1998). https://doi.org/10.1007/PL00005184
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DOI: https://doi.org/10.1007/PL00005184