Distribution of alpha(1)-adrenoceptor subtype proteins in different tissues of neonatal and adult rats

Distribution of alpha(1)-adrenoceptor (alpha(1)AR) subtype (alpha(1A), alph a(1B), alpha(1D)) proteins in brain, heart, kidney, and liver of 1-week-old rats and in brain, heart, aorta, kidney, liver, vas deferens, prostate, an d adrenal glands of adult rats was investigated by Western analysis, using receptor subtype specific polyclonal antibodies. High levels of immunoreact ive alpha(1A)AR and alpha(1D)AR in brain and heart and of alpha(1B)AR in li ver and heart of neonatal rats were detected. In adult rat tissues, the abu ndance of alpha(1A)AR protein was most marked in the brain, intermediate in heart, aorta, liver, vas deferens, and adrenals, and minimal in the kidney and prostate; relative to other tissues, the expression of alpha(1B)AR was higher in brain and heart and that of alpha(1D)AR in brain. All the three receptor subtypes increased with age in the brain cortex, whereas the abund ance of alpha(1B)AR increased in the heart but decreased in the liver; alph a(1A)AR and alpha(1D)AR in liver, kidney, and heart were not affected by ag e. It is concluded that alpha(1)AR subtypes are widely expressed in differe nt neonatal and adult rat tissues.