Characterization of serotonergic receptors in rabbit, porcine and human conjunctivae

Purpose. To characterize the serotonin (5-HT) receptors linked to the modulation of adenylyl cyclase activity in rabbit, porcine and human conjunctivae. Methods. Serotonin receptor-subtype expression was examined using reverse transcription-polymerase chain reaction (RT-PCR) and receptor subtype-specific polyclonal antibodies for the immunofluorescent labeling of conjunctival cryosections. In addition, measurements of the effects of serotonergics on the short-circuit current (I sc) across rabbit and porcine conjunctivae were contrasted. Results. RT-PCR assays indicated the expression of 5-HT 1B and 5-HT 1D receptors, subtypes negatively coupled to adenylyl cyclase, in the rabbit conjunctiva. This approach also suggested the co-expression of 5-HT 1B, 5-HT 1D, 5-HT 1F, 5-HT 4 and 5-HT 7 mRNA’s in the porcine conjunctiva, and 5-HT 1D, 5-HT 1F and 5-HT 7 in the human conjunctiva. Since the 5-HT 4 and 5-HT 7 receptors are positively linked to adenylyl cyclase, these results implied that the porcine and human t...