Dóra E, Kovách A G
J Cereb Blood Flow Metab. 1983 Jun;3(2):161-9. doi: 10.1038/jcbfm.1983.23.
We investigated the effects of topically administered catecholamines and acetylcholine (ACh) on the cerebrocortical microcirculation and NAD/NADH redox state in chloralose-anesthetized cats. NADH fluorescence of the brain cortex and the volume of small intracortical vessels were measured by fluororeflectometry, and in most of the experiments the pial vessels were photographed simultaneously through a cranial window. Cerebrocortical vascular volume (CVV) and the diameter of the pial vessels were decreased, and NADH was oxidized by concentrations of epinephrine and norepinephrine as low as 3 x 10(-8) M. Pial veins constricted approximately twice as much as pial arteries. ACh dilatated pial arteries, slightly constricted pial veins, and increased CVV, but had no effect on the NAD/NADH redox state. Since pial and intracortical vessels were constricted markedly by catecholamines, and since these vascular reactions appeared at a lower concentration than is presumed to occur in the synaptic cleft, our results support the regulating role of these substances in cerebral circulation. NADH oxidation, obtained with catecholamines, was interpreted to be due to enhanced tissue respiration. The finding that ACh dilatated pial arteries and increased CVV, but failed to influence the NAD/NADH redox state, might indicate that the brain cortices of normal animals are bioenergetically nonhypoxic. If cortical microregions where the oxygen tension is close to zero were biochemically hypoxic, NADH oxidation should have occurred during ACh administration.
我们研究了局部应用儿茶酚胺和乙酰胆碱（ACh）对水合氯醛麻醉猫的大脑皮质微循环和NAD/NADH氧化还原状态的影响。通过荧光反射法测量大脑皮质的NADH荧光和皮质内小血管的容积，并且在大多数实验中，通过颅骨开窗同时拍摄软脑膜血管。大脑皮质血管容积（CVV）和软脑膜血管直径减小，低至3×10⁻⁸ M的肾上腺素和去甲肾上腺素浓度即可使NADH氧化。软脑膜静脉收缩程度约为软脑膜动脉的两倍。ACh使软脑膜动脉扩张，使软脑膜静脉轻度收缩，并增加CVV，但对NAD/NADH氧化还原状态无影响。由于儿茶酚胺可使软脑膜和皮质内血管明显收缩，且这些血管反应出现在低于推测在突触间隙中发生的浓度时，我们的结果支持这些物质在脑循环中的调节作用。儿茶酚胺引起的NADH氧化被解释为由于组织呼吸增强。ACh使软脑膜动脉扩张并增加CVV，但未影响NAD/NADH氧化还原状态这一发现，可能表明正常动物的大脑皮质在生物能量方面没有缺氧。如果氧张力接近零的皮质微区在生化方面缺氧，那么在给予ACh期间应该会发生NADH氧化。
