Bie P, Wang B C, Leadley R J, Goetz K L
Division of Experimental Medicine, St. Luke's Hospital and Foundation, Kansas City, Missouri 64111.
Am J Physiol. 1988 Feb;254(2 Pt 2):R161-9. doi: 10.1152/ajpregu.1988.254.2.R161.
The effects of alpha-human atrial natriuretic peptide (alpha-hANP) on cardiovascular and renal function in conscious dogs were evaluated in two experimental protocols. In one protocol, alpha-hANP was infused intravenously at increasing rates of 50, 100, and 200 ng.min-1.kg-1 (stepup infusion) during successive 20-min periods. The greatest responses occurred during the final 20-min period of the stepup infusion when the plasma concentration of immunoreactive atrial natriuretic peptide (irANP) was increased by 44-fold over preinfusion values; pressures in the aorta and both atria were decreased at this time, whereas glomerular filtration rate, urine flow, and sodium excretion were increased. In a second protocol, alpha-hANP was infused for 1 h at constant rates of either 12.5, 25, or 50 ng.min-1.kg-1; these constant infusions increased plasma irANP by 3-, 7-, and 12-fold, respectively. Each infusion rate decreased left and right atrial pressures and increased urine flow and sodium excretion. The two lowest infusion rates elevated plasma irANP to levels that would be expected to occur only during unusual physiological, or perhaps pathophysiological, conditions. The two highest infusion rates decreased plasma renin activity. Nevertheless, the accompanying maximal increases in sodium excretion were modest (41-72%). These data imply that small changes in circulating atrial peptides that presumably occur under normal physiological conditions would not have a dominant effect on the regulation of sodium excretion; the peptides may, however, play a modulatory role on sodium excretion under these conditions. It remains to be determined whether the ability of atrial peptides to lower cardiac filling pressures is of physiological significance.
在两个实验方案中评估了α-人心房利钠肽（α-hANP）对清醒犬心血管和肾功能的影响。在一个方案中，在连续20分钟的时间段内，以50、100和200 ng·min⁻¹·kg⁻¹的递增速率静脉输注α-hANP（逐步递增输注）。在逐步递增输注的最后20分钟期间出现最大反应，此时免疫反应性心房利钠肽（irANP）的血浆浓度比输注前值增加了44倍；此时主动脉和两个心房的压力降低，而肾小球滤过率、尿流量和钠排泄增加。在第二个方案中，以12.5、25或50 ng·min⁻¹·kg⁻¹的恒定速率输注α-hANP 1小时；这些恒定输注分别使血浆irANP增加了3倍、7倍和12倍。每个输注速率均降低了左、右心房压力，并增加了尿流量和钠排泄。两个最低输注速率将血浆irANP升高到仅在异常生理或可能病理生理条件下才会出现的水平。两个最高输注速率降低了血浆肾素活性。然而，伴随的钠排泄最大增加幅度适中（41%-72%）。这些数据表明，在正常生理条件下可能发生的循环心房肽的微小变化对钠排泄的调节不会产生主导作用；然而，在这些条件下，这些肽可能对钠排泄起调节作用。心房肽降低心脏充盈压力的能力是否具有生理意义仍有待确定。
