Aharinejad S, Egerbacher M, Nourani F, Böck P, Friederici C, Schraufnagel D E
Department of Anatomy, University of Vienna, Austria.
Anat Rec. 1996 Nov;246(3):356-63. doi: 10.1002/(SICI)1097-0185(199611)246:3<356::AID-AR6>3.0.CO;2-W.
The pulmonary veins of rats have regular focal narrowing by tufts of smooth muscle (sphincters) that can contract in response to a variety of stimuli, but these structures are not well studied in other species, and there is little information about their innervation and control.
The pulmonary veins of 21 cattle were cast with methacrylate, and the casts were studied by scanning electron microscopy, or the fixed tissue was studied by light microscopy with immunocytochemistry and transmission electron microscopy.
Constrictions occurred in series along the course of veins (9.6/500 microns), giving the cast veins a string-of-pearl look, with narrowing of 33-81% of the outer diameter. No resin appeared beyond the most narrowed veins. The percentage of contraction did not correlate with the diameter of the veins. With immunohistochemistry using antibodies to S-100, protein gene peptide 9.5, neuron-specific enolase, neurofilament 200, and glial fibrillary acidic protein and with transmission electron microscopy, we could identify no neuronal elements associated with the venous smooth muscle tufts. Bronchial smooth muscle bundles in the same sections stained positively.
The veins of cattle are unlike the rat because the focal venous smooth muscle protrudes deeply into the venous lumen and may completely obstruct perfusion. If the focal venous muscle has no innervation (this study) and can constrict without blood flow (as shown previously), then the venous constriction and, hence, local blood flow regulation must be controlled by local mediators.
大鼠肺静脉有由平滑肌束（括约肌）引起的规则性局灶性狭窄，这些平滑肌束可对多种刺激产生收缩反应，但在其他物种中对这些结构的研究较少，关于其神经支配和控制的信息也很少。
用甲基丙烯酸酯对21头牛的肺静脉进行铸型，通过扫描电子显微镜研究铸型，或通过免疫细胞化学和透射电子显微镜的光学显微镜研究固定组织。
在静脉走行过程中出现一系列狭窄（9.6/500微米），使铸型静脉呈现串珠样外观，外径狭窄33% - 81%。在最狭窄的静脉之外没有树脂出现。收缩百分比与静脉直径无关。使用针对S - 100、蛋白基因肽9.5、神经元特异性烯醇化酶、神经丝200和胶质纤维酸性蛋白的抗体进行免疫组织化学以及透射电子显微镜检查，我们未发现与静脉平滑肌束相关的神经元成分。同一切片中的支气管平滑肌束呈阳性染色。
牛的静脉与大鼠不同，因为局灶性静脉平滑肌深深突入静脉腔，可能完全阻塞灌注。如果局灶性静脉肌无神经支配（本研究）且能在无血流情况下收缩（如先前所示），那么静脉收缩以及局部血流调节必定由局部介质控制。
