Toda N, Okamura T, Miyazaki M
Eur J Pharmacol. 1984 Nov 13;106(2):291-9. doi: 10.1016/0014-2999(84)90716-7.
Responses to vasoconstrictor agents were compared in helical strips of proximal and distal middle cerebral arteries isolated from the same dogs. Contractions induced by 30 mM K+ per cross-sectional areas in the large and small artery strips did not differ significantly so that contractions induced by the agents could be compared relative to those induced by K+. The contractions induced by serotonin were greater in the proximal than in the distal arteries. Histamine produced a greater contraction in the proximal arteries under resting conditions. Distal arteries partially precontracted with prostaglandin F2 alpha responded to histamine with relaxations. The histamine-induced contraction was attenuated by chlorpheniramine, whereas the relaxation was suppressed by cimetidine. Prostaglandin F2 alpha or carbocyclic thromboxane A2 produced similar magnitudes of contractions in the proximal and distal arteries. Thrombin contracted the distal arteries to a greater extent. Contractions induced by norepinephrine or bradykinin did not differ in the proximal and distal arteries. It may be concluded that the ratio of histaminergic H1 and H2 receptor functions decreases peripherally along middle cerebral arteries, whereas the contractile response to bradykinin was not influenced in these arteries of a relatively short distance. The functions of receptor sites for serotonin and thrombin appear to be quite different in large and small cerebral arteries of such a short distance, but alpha-adrenoceptor functions seem to be identical.
在从同一只犬分离出的大脑中动脉近端和远端的螺旋条带中比较了对血管收缩剂的反应。大动脉条带和小动脉条带中每横截面积30 mM K⁺诱导的收缩无显著差异，因此可以将这些药剂诱导的收缩与K⁺诱导的收缩相比较。5-羟色胺诱导的近端动脉收缩大于远端动脉。在静息条件下，组胺在近端动脉产生更大的收缩。用前列腺素F2α部分预收缩的远端动脉对组胺产生舒张反应。氯苯那敏减弱组胺诱导的收缩，而西咪替丁抑制舒张反应。前列腺素F2α或碳环血栓素A2在近端和远端动脉产生的收缩幅度相似。凝血酶使远端动脉收缩程度更大。去甲肾上腺素或缓激肽诱导的近端和远端动脉收缩无差异。可以得出结论，组胺能H1和H2受体功能的比例沿大脑中动脉外周降低，而在相对较短距离的这些动脉中，对缓激肽的收缩反应不受影响。在如此短距离的大脑大动脉和小动脉中，5-羟色胺和凝血酶受体位点的功能似乎有很大不同，但α-肾上腺素能受体功能似乎相同。
