THE DISTRIBUTION CHARACTERISTICS AND EFFECTS OF BNP IN CENTRAL AND PERIPHERAL TISSUES IN RATS

【摘要】 <正> The present study first investigated the existence, distribution, biochemical characteristics and biological effects of immunoreactive brain natriuretic peptidc (ir-BNP), a novel natriuretic peptide, in central nervous system and some perpheral tissues in rats, Using the highly specific radioimmunoassay, we found that ir-BNP was .distributed in the hypothalamus, spinal cord, pituitary, atrium and lung, the highest content was in the atrium (2.86±0.31pmol/g tissue) and the lowest in the pituitary (0.01±0.002pmol pituitary), the concentration of plasma ir-BNP was 11.65pg/ml. Hypothalamus ir-BNP was mainly present in the nerve fibers of the lateral hypothalamus and the atrial ir-BNP mainly in the cardiocytes by immunohistochemical method. Two (high and low) molecular forms of ir-BNP were found in tissues by the gel filtration chromatography and HPLC, the ratio of the high molecular weight ir-BNP to the low molecular form was 1:1.2-2.7. The bioactivity of vasodilation effect of the low molecular form was更多还原

【Abstract】 The present study first investigated the existence, distribution, biochemical characteristics and biological effects of immunoreactive brain natriuretic peptidc (ir-BNP), a novel natriuretic peptide, in central nervous system and some perpheral tissues in rats, Using the highly specific radioimmunoassay, we found that ir-BNP was .distributed in the hypothalamus, spinal cord, pituitary, atrium and lung, the highest content was in the atrium (2.86±0.31pmol/g tissue) and the lowest in the pituitary (0.01±0.002pmol pituitary), the concentration of plasma ir-BNP was 11.65pg/ml. Hypothalamus ir-BNP was mainly present in the nerve fibers of the lateral hypothalamus and the atrial ir-BNP mainly in the cardiocytes by immunohistochemical method. Two (high and low) molecular forms of ir-BNP were found in tissues by the gel filtration chromatography and HPLC, the ratio of the high molecular weight ir-BNP to the low molecular form was 1:1.2-2.7. The bioactivity of vasodilation effect of the low molecular form was much higher than that of high molecular form. It was found that the specific BNP receptor presented in central nervous system using radioreceptor analysis, the Scatchard plot analysis revealed that Kd was 0.16nM and Bmex was 57.8fmol/mg protein, the binding site of BNP was not only binding to BNP, but also to ANP. BNP, like ANP, could dilate aorta (IC 50 = 2.6×10-7M) in vitro.These data suggested that BNP, like ANP, is a novel neurotransmitter and a circulatory hormone, widely distributed in various tissues and involved in the regulation of water-electrolytes balance and cardiovascular activity.更多还原