Molecular characterization and in situ localization of a full-length cyclic nucleotide-gated channel in rat brain

Ion channels gated directly by cyclic nucleotides are required for the tran sduction of sensory signals in photoreceptor cells and olfactory cells. Cyc lic nucleotide-gated (CNG) channels may also be expressed in the central ne rvous system because partial transcripts that share homology with CNG chann els have been found therein. We have now isolated and cloned a full-length CNG channel cDNA from adult rat brain. The sequence is identical to that of the alpha-subunit originally found in the olfactory epithelium (CNC alpha 3). In situ hybridization, using probes specific for the CNC alpha 3 mRNA, suggest that this channel is expressed widely in the rat brain, albeit most ly at relatively low levels. Certain neuronal populations, however, such as deep cerebellar nuclei, olfactory bulb mitral cells and cerebellar Purkinj e neurons, appeared specially enriched. The study demonstrates for the firs t time that a full-length CNG channel mRNA is expressed in the brain, suppo rting the possibility that CNG channels are involved in central neural comm unication and plasticity. The sequence reported in this paper has been depo sited in the GenBank data base (accession no. AF126808).