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 hybridization and Northern blot analysis. The 851-bp SmaI/PvuII fragment of human β1- adrenoceptor cDNA, the 439-bp SmaI fragment of human β2-adrenoceptor cDNA and the 975-bp SmaI fragment of human β2-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 β1- and β2-adrenoceptor mRNAs with no detectable level of β3-adrenoceptor mRNA, while rabbit perirenal adipose tissue expressed β1-, β2 and β3- adrenoceptor mRNAs. Cultured human airway epithelial cells and airway smooth muscle cells expressed only β2-adrenoceptor mRNA. In situ hybridization in human lung, using 35S-labelled antisense RNA probes revealed a high level of expression of β1- and β2-adrenoceptor mRNAs in the pulmonary blood vessels, high level of expression of β2-adrenoceptor mRNA in the alveolar walls with less expression of β1-adrenoceptor mRNA. There was a moderate expression of β2-adrenoceptor but not β1-adrenoceptor mRNA in airway epithelium and smooth muscle of peripheral airways and no detectable β3- adrenoceptor mRNA in any lung structures.