大脑血管内胆碱乙酰转移酶免疫反应活性(英文)

本文采用间接免疫荧光染色(双抗体法)和非标记抗体-过氧化物酶-抗过氧化物酶法(PAP法),使用抗纯化胆碱乙酰转移酶(CHAT)抗体,对猫和猪各种体积的脑软膜动静脉,脑实质内微血管以及脉络丛的乙酰胆碱能神经的存在和分布进行了研究。 结果表明,脑软膜动静脉的ChAT免疫反应性神经主要是成束状的,只有少数是由细小纤维组成,静脉的此类神经供应少于其动脉供应程度,同时,ChAT免疫反应纤维的密度又与血管的体积成比例,在小分枝的动静脉上(外径小于30μm)通常观察不到此类纤维的存在,脉络丛的动静脉有ChAT免疫反应性神经存在,但此类神经在实质内微血管则观察不到,以上结果与以前报告过的颅内和实质外动脉的乙酰胆碱酯酶(AChE)性纤维的密度比同类静脉所存在密度大的结果相符,而ChAT免疫反应纤维分布的方式则与报告过的AChE性纤维的分布方式不同,后者主要是由细小纤维组成,尽管离体的实质内微血管无ChAT免疫反应纤维,但胆碱能神经接近和“突触化”此类微血管的可能性不能排除,脑软膜血管一些内皮细胞胞浆内也有ChAT免疫反应活性存在,因此,本文结果与神经元和血管内皮两者的胆碱能机构在控制脑循环中起着重要作用之假说相一致。

Choline acetyltransferase immunoreactivities in cerebral blood vessels

The presence and distribution ofcholinergic nerves in pial arteries and veins of various sizes, intraparenchymal microvessels and choroid plexus in the cat and pig were examined by both indirect immunofluorescence and unlabelled antibody peroxidase-antiperoxidase (PAP) methods using antibodies against purified choline acetyltransferase (ChAT). ChAT-immunoreactive (ChAT-I) nerves, which are mostly as bundles and few fine fibers, are present in arteries and veins. The pial veins receive a sparser supply of ChAT-I fibers than do the pial arteries. The density of ChAT-I fibers appears to be proportional to the size of vessels. Smaller branch arteries and veins (O.D. smaller than 30 μm) usually receive no ChAT-I fibers. The arteries and veins of choroid plexus also receive ChAT-I nerves. No ChAT-I nerves were found to be associated with isolated intraparenchymal microvessels. These results are consistent with the previous reports that intracranial and extraparenchymal vessels receive acetylcholinesterase (AChE)-containing fibers, which are denser in arteries than in veins. The distribution patterns of ChAT-I fibers, however, are different from reported AChE-con-taining fibers which consist of more fine fibers than bundles. Although the isolated intraparenchymal microvessels receive no ChAT-I fibers, the possibility that cholinergic nerves may approach and"synapse" on these microvessels can not be ruled out. ChAT-immunoreactivity was also found in the cytoplasm of some endothelial cells of the pial vessels. These results are consistent with the hypothesis that both neuronal and endothelial cholinergic mecha-nisms play an important role in controlling brain circulation.