Ursell P C, Mayes M
Department of Pathology, University of California at San Francisco 94143-0506, USA.
Anat Rec. 1996 Dec;246(4):465-72. doi: 10.1002/(SICI)1097-0185(199612)246:4<465::AID-AR6>3.0.CO;2-U.
Although nitric oxide seems important to cardiovascular function, the ontogenesis of this chemical messenger in the heart is unknown. To investigate this issue, we determined the distribution of nitric oxide synthase (NOS) in the rat heart at different stages during development.
Immunohistochemistry and the NADPH-diaphorase reaction were used to localize NOS activity-specifically, the endothelial isoform (eNOS) and neuronal isoform (bNOS)-in fetal (14- and 18-day gestation), neonatal (0-, 3-, and 6-day gestation), 12-day-old, 1-month-old, and mature adult Fischer 344 rat hearts.
There was sparse eNOS immunoreactivity in the endocardium of the youngest fetal hearts; antibody to eNOS did not localize any vessels within the noncompact myocardium at this stage. By the eighteenth day of embryonic development (e18), eNOS was present not only in endocardium but also in the intima of numerous small vessels within the compact myocardium. In the neonatal rat heart, vascular eNOS predominated, with extensive reaction product in arteries, veins, and numerous capillary size vessels within the myocardium; the endocardium also contained eNOS immunoreactivity. A similar distribution was maintained throughout the remainder of development. Only rare bNOS-immunoreactive neurons were detected in hearts at the three oldest ages.
(1) At e14, eNOS is confined to the endocardium of the developing rat heart; (2) as the myocardium becomes compact, vascular eNOS predominates over endocardial eNOS; (3) at birth, there is extensive eNOS in a distribution similar to the mature pattern; and (4) there is very little bNOS-immunoreactive neural tissue in the rat heart at any stage.
尽管一氧化氮似乎对心血管功能很重要，但这种化学信使在心脏中的发生过程尚不清楚。为了研究这个问题，我们确定了发育过程中不同阶段大鼠心脏中一氧化氮合酶（NOS）的分布。
采用免疫组织化学和NADPH - 黄递酶反应来特异性定位NOS活性，即内皮型（eNOS）和神经元型（bNOS），研究对象为胎龄14天和18天、新生（出生0天、3天和6天）、12日龄、1月龄以及成年成熟的Fischer 344大鼠心脏。
在最幼小的胎儿心脏的心内膜中，eNOS免疫反应性稀疏；在此阶段，eNOS抗体未在致密心肌内的任何血管中定位。到胚胎发育第18天（e18），eNOS不仅存在于心内膜，还存在于致密心肌内众多小血管的内膜中。在新生大鼠心脏中，血管eNOS占主导，动脉、静脉以及心肌内众多毛细血管大小的血管中有广泛的反应产物；心内膜也含有eNOS免疫反应性。在发育的其余阶段保持类似的分布。在三个最老年龄组的心脏中仅检测到罕见的bNOS免疫反应性神经元。
（1）在e14时，eNOS局限于发育中大鼠心脏的心内膜；（2）随着心肌变得致密，血管eNOS超过心内膜eNOS占主导；（3）出生时，有广泛的eNOS分布与成熟模式相似；（4）在大鼠心脏的任何阶段，bNOS免疫反应性神经组织都很少。
