Rebuffat P, Mazzocchi G, Coi A, Gottardo G, Nussdorfer G G
Department of Anatomy, University of Padua, Italy.
Anat Anz. 1989;169(2):149-55.
The effects of chronic water/sodium restriction and acute water/sodium load on the "specific granule" population of rat atrial cardiocytes were investigated by stereology. The volume density (Vv) of atrial granules, which contain atrial natriuretic peptide (ANP), displayed a 135%-rise in water/sodium-restricted animals. The injection of 2.5 ml of isotonic saline to water/sodium-restricted rats provoked a striking degranulation of atrial myoendocrine cells (Vv of granules decreased by about 31%). The administration of an equal volume of hypertonic (5%) saline caused a more pronounced effect (Vv decreased by about 51%). These findings are in agreement with the view that chronic water/sodium restriction blocks the exocytotic release of atrial granules, without lowering the rate of their production. Moreover, they suggest that not only blood volume expansion, but also sodium ions can be a potent stimulating factor of ANP release.
通过体视学方法研究了慢性水/钠限制和急性水/钠负荷对大鼠心房心肌细胞“特异性颗粒”群体的影响。含有心房利钠肽（ANP）的心房颗粒的体积密度（Vv）在水/钠限制的动物中显示出135%的升高。向水/钠限制的大鼠注射2.5 ml等渗盐水会引起心房肌内分泌细胞显著的脱颗粒（颗粒的Vv降低约31%）。给予等体积的高渗（5%）盐水会产生更明显的效果（Vv降低约51%）。这些发现与以下观点一致，即慢性水/钠限制会阻断心房颗粒的胞吐释放，而不会降低其产生速率。此外，它们表明不仅血容量扩张，而且钠离子也可以是ANP释放的有效刺激因子。
