脑钠素对心钠素分泌的影响

脑钠素(brain natriuretic peptide,BNP)是由26个氨基酸组成的多肽,其结构和功能与心钠素(atrial natriuretic peptide,ANP)极为相似,且两者在体内作用于同一受体,因而BNP与ANP的分泌可能互相影响,对此我们做了初步研究。结果表明,给大鼠静脉滴注BNP(40μg/kg)可使心房中ANP含量和血中ANP浓度明显增加,同时血中神经肽Y(Neuropeptide Y)浓度也明显升高。而体内外灌流实验表明,BNP不能直接刺激心房分泌ANP。我们认为,BNP引起血中ANP浓度的增加是由于BNP与ANP竞争同一受体引起的。BNP占据了ANP受体而使得与ANP结合的受体减少,其结果导致心房合成和分泌ANP增加。BNP引起的NPY浓度升高是机体对BNP引起的血压降低的代偿性反应。

Effect of Brain Natriuretic Peptide on Secretion of Atrial Natriuretic Peptide in Rats

Brain natriuretic peptide (BNP) is a 26 amino acid peptide which not only shows a high sequence homology to atrial natriuretic peptide (ANP), but also has very similar pharmacological effects to that of ANP. It have also been found that BNP interacts with ANP receptor. We consider that the secretions of BNP and ANP must interrelate and interact with each other. Based on that fact, we conducted the present study. Our results show that the infusion of BNP (40ug/kg) for 60 minutes leads to an increase of both ANP level in plasma and ANP content in atria, In vitro BNP (10mol/L) perfusion cannot stimulate the atrium to secrete ANP. We consider that the increase of both ANP level in plasma and ANP content in atriums is a result of an increase of synthesis and secretion of ANP in atria, but it is not a direct effect of BNP on atria. We infer that because of the binding of BNP to ANP receptor, there is a decrease in quantity of ANP receptors and it leads to a compensatory increase of ANP. We also found that NPY plasma concentration increased foolowing the infusion of BNP. We consider that it is a result of conpensation to weaken the vasodilatory effect of BNP on arteries.