LOCALIZATION AND EXPRESSION OF BETA-ADRENOCEPTOR SUBTYPE MESSENGER-RNAS IN HUMAN LUNG

The cellular localisation and distribution of mRNAs encoding beta-adre noceptor subtypes in human lung were studied by in situ hybridisation and Northern blot analysis. The 851-bp SmaI/PvuII fragment of human be ta(1)-adrenoceptor cDNA, the 439-bp SmaI fragment of human beta(2)-adr enoceptor cDNA and the 975-bp SmaI fragment of human beta(3)-adrenocep tor cDNA bound to single mRNA species of approximately 3.2 kb, 2.2 kb and 2.3 kb in size, respectively. Human lung and heart and rabbit lung expressed both beta(1)- and beta(2)-adrenoceptor mRNAs with no detect able level of beta(3)-adrenoceptor mRNA, while rabbit perirenal adipos e tissue expressed beta(1)-, beta(2)- and beta(3)-adrenoceptor mRNAs. Cultured human airway epithelial cells and airway smooth muscle cells expressed only beta(2)-adrenoceptor mRNA. In situ hybridisation in hum an lung, using S-35-labelled antisense RNA probes revealed a high leve l of expression of beta(1)- and beta(2)-adrenoceptor mRNAs in the pulm onary blood vessels, high level of expression of beta(2)-adrenoceptor mRNA in the alveolar walls with less expression of beta(1)-adrenocepto r mRNA. There was a moderate expression of beta(2)-adrenoceptor but no t beta(1)-adrenoceptor mRNA in airway epithelium and smooth muscle of peripheral airways and no delectable beta(3)-adrenoceptor mRNA in any lung structures.