AND LOCALIZATION OF A G-PROTEIN-COUPLED INWARDLY RECTIFYING K+ CHANNEL IN THE RAT

The cellular distribution of the mRNA of the inwardly rectifying K+ ch annel KGA (GIRK1) was investigated in rat tissue by in situ hybridizat ion. KGA was originally cloned from the heart and represents the first G protein-activated K+ channel identified. It is expressed in periphe ral tissue solely in the atrium, but not in the ventricle, skeletal mu scle, lung and kidney. In the central nervous system KGA is most promi nently expressed in the Ammon's horn and dentate gyrus of the hippocam pus, neocortical layers II-VI, cerebellar granular layer, olfactory bu lb, anterior pituitary, thalamic nuclei and several distinct nuclei of the lower brainstem. The abundant expression of KGA in many CNS neuro ns supports its important role as a major target channel for G protein mediated receptor function.