Selective expression of serotonin receptor transcripts in the mammalian cochlea and its subdivisions

Expression of serotonin receptor (5-HTR) mRNA has been determined in the ma mmalian cochlea and its subdivisions by reverse transcriptase-polymerase ch ain reaction (RT-PCR) analysis. Specific primers targeting individual 5-HTR s 1-7 directed amplification of 5-HTR subtypes 1A, 1B, 2B, 2C, 3, 5B, and 6 from mouse cochlea cDNA. No evidence of expression was obtained for 5-HTRs 1D, 2A, 4 (L and S), 5A, and 7. The distribution of receptor mRNA within t he cochlea was determined with application of RT-PCR to morphologically def ined microdissected subfractions of the rat cochlea. Messages for 5-HTR sub types 1A, 1B, 2B, and 6 were present in the organ of Corti, lateral wall, a nd spiral ganglion subfractions. Messages for 5-HTR subtypes 2C, 3 and 5B w ere found in the spiral ganglion, but not in the organ of Corti or lateral wall fractions. The existence of transcripts for 5-HTRs 1A, IB, 2B and 6 in the organ of Corti is consistent with a role for these receptors in seroto nin-mediated modulation of the mechanosensory signal. (C) 1999 Elsevier Sci ence B.V. All rights reserved.