A Schneider1, P Riess, A Elbers, E Neugebauer, U Schaefer. 1. Biochemical and Experimental Division, II. Department of Surgery, University of Cologne, Ostmerheimer Str. 200, 51109 Cologne, Germany.
Abstract
OBJECTIVE AND DESIGN: One of the factors defining cellular response might be the distribution and density of receptor subtypes on cell membranes. It was our aim to quantify and compare histamine H2 receptor expression in primary vascular cell types. We have therefore generated antibodies directed against the second extra-cellular loop of the H2 receptor. METHODS: The specificity of polyclonal anti-H2 receptor antibodies designed for this purpose was examined by Western blot analysis and immunohistochemistry. H2 receptor expression was quantified by ELISA. Regulation of H2 receptor gene expression was analyzed by competitive RT-PCR. RESULTS: Our results indicate that the polyclonal antibodies specifically interact with the histamine H2 receptor. Furthermore, utilizing these antibodies we were able to show significant differences in H2 receptor levels in human umbilical arterial and vein endothelial cells as well as smooth muscle cells. CONCLUSIONS: We conclude that the antibodies generated against the extra-cellular domain of the H2 receptor are specific and can be utilized to detect and quantify H2 receptor expression. Furthermore, the significant differences in H2 receptor expression in different vascular cell types might play a critical role in defining histamine induced cellular responses during physiological or pathophysiological processes.
OBJECTIVE AND DESIGN: One of the factors defining cellular response might be the distribution and density of receptor subtypes on cell membranes. It was our aim to quantify and compare histamine H2 receptor expression in primary vascular cell types. We have therefore generated antibodies directed against the second extra-cellular loop of the H2 receptor. METHODS: The specificity of polyclonal anti-H2 receptor antibodies designed for this purpose was examined by Western blot analysis and immunohistochemistry. H2 receptor expression was quantified by ELISA. Regulation of H2 receptor gene expression was analyzed by competitive RT-PCR. RESULTS: Our results indicate that the polyclonal antibodies specifically interact with the histamine H2 receptor. Furthermore, utilizing these antibodies we were able to show significant differences in H2 receptor levels in human umbilical arterial and vein endothelial cells as well as smooth muscle cells. CONCLUSIONS: We conclude that the antibodies generated against the extra-cellular domain of the H2 receptor are specific and can be utilized to detect and quantify H2 receptor expression. Furthermore, the significant differences in H2 receptor expression in different vascular cell types might play a critical role in defining histamine induced cellular responses during physiological or pathophysiological processes.