Localisation and expression of β-adrenoceptor subtype mRNAs in human lung

Abstract

The cellular localisation and distribution of mRNAs encoding β-adrenoceptor subtypes in human lung were studied by in situ hybridisation and Northern blot analysis. The 851-bp SmaI/PvuII fragment of human β 1-adrenoceptor cDNA, the 439-bp SmaI fragment of human β 2-adrenoceptor cDNA and the 975-bp SmaI fragment of human β 3-adrenoceptor 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 β 1- and β 2-adrenoceptor mRNAs with no detectable level of β 3-adrenoceptor mRNA, while rabbit perirenal adipose tissue expressed β 1-, β 2- and β 3-adrenoceptor mRNAs. Cultured human airway epithelial cells and airway smooth muscle cells expressed only β 2-adrenoceptor mRNA. In situ hybridisation in human lung, using 35S-labelled antisense RNA probes revealed a high level of expression of β 1- and β 2-adrenoceptor mRNAs in the pulmonary blood vessels, high level of expression of β 2-adrenoceptor mRNA in the alveolar walls with less expression of β 1-adrenoceptor mRNA. There was a moderate expression of β 2-adrenoceptor but not β 1-adrenoceptor mRNA in airway epithelium and smooth muscle of peripheral airways and no detectable β 3-adrenoceptor mRNA in any lung structures.