Induction of odorant-evoked current transients in Xenopus oocytes injected with mRNA isolated from the olfactory mucosa of Rana pipiens.

Total mRNA isolated from the olfactory mucosa of the frog, Rana pipiens, and from rat pup brains was microinjected into mature oocytes isolated from Xenopus laevis. Both populations of voltage-clamped oocytes as well as controls were non-responsive to an odorant mixture and other ligands two days later. On the 3rd day, oocytes microinjected with rat brain mRNA responded to 5-hydroxytryptamine but not to an odorant mixture, while oocytes injected with Rana pipiens olfactory mucosal mRNA responded to an odorant mixture but not to other ligands. The magnitude of the small-amplitude, long-duration inward current transients recorded in response to odorant stimulation was enhanced by preincubating the oocytes with 8-bromo cAMP. The data suggest that odorant-gated ion channels associated with sensory transduction in the primary olfactory system were translated and inserted into the oocyte membrane. The results also indicate that the Xenopus oocyte system may be a useful preparation in which to investigate further the expression of membrane events associated with olfactory transduction.