PATTERNS OF MESSENGER-RNA EXPRESSION FOR ADRENERGIC-RECEPTOR SUBTYPESIN THE RAT-KIDNEY

The distribution of mRNA for the rat alpha-1A/D, alpha-1B, alpha-2A/D (RG20), alpha-2B (RNG), alpha-2C (RG10), beta-1 and beta-2 adrenergic receptors were studied in the rat kidney using in situ hybridization. After hybridized sections were exposed to autoradiography film or dipp ed in photographic emulsion and counterstained with hematoxylin and eo sin, specific and selective labeling patterns characteristic for each probe in the kidney were observed. Labeling with the probe to the alph a-1A/D receptor was only observed in vessels in the renal parenchyma a nd in the ureter. Alpha-1B receptor mRNA was demonstrated in the outer and inner stripe of the outer medulla, corresponding to segment S3 of proximal tubules and the thick ascending limb of loop of Henle. Alpha -2A/D receptor mRNA was distributed in the inner stripe of the outer m edulla and in the inner medulla, corresponding to collecting tubules, and in the ureter. The strongest signal in the kidney was obtained wit h the alpha-2B receptor probe, showing labeling in the outer stripe of the outer medulla with tubular rays radiating into the cortex, coinci ding with segment S3 of proximal tubules. Weak labeling obtained with the alpha-2C receptor probe was present in the renal medulla. Labeling obtained with the probe to the beta-1 receptor was seen in the entire cortex and to a lesser extent also in the outer medulla. In addition, beta-1 receptor mRNA was shown in perirenal adipose tissue and in the ureter. Labeling obtained with the probe to the beta-2 receptor was d emonstrated in the outer and inner stripe of the outer medulla. The re sults show that adrenoceptor mRNA are found in unique, Let sometimes o verlapping, regions of the kidney and therefore may have unique roles in renal physiology.-