Alborch E, Torregrosa G, Terrasa J C, Estrada C
Brain Res. 1984 Oct 29;321(1):103-10. doi: 10.1016/0006-8993(84)90685-1.
The effects of gamma-aminobutyric acid (GABA) and muscimol upon cerebral blood flow were evaluated in the unanesthetized goat. Cerebral blood flow was continuously measured by means of an electromagnetic flow probe chronically implanted on the internal maxillary artery after occlusion and thrombosis of the distal extracerebral vessels. Administration of GABA (1-100 micrograms) directly into the cerebral circulation produced dose-dependent increases in cerebral blood flow, without accompanying systemic effects. Muscimol mimicked the effects of GABA at doses 10 times lower. Administration of picrotoxin (1-3 mg) into the internal maxillary artery did not significantly change cerebral blood flow, but inhibited in a dose-dependent manner the vasodilation induced by GABA. Selective blockade of beta-adrenergic or muscarinic cholinergic receptors by propranolol or atropine, respectively, did not modify the cerebrovascular response to the GABAergic agonists. These results indicate that GABA increases total cerebral blood flow, acting on specific receptor sites in the cerebral blood vessels. The absence of influence of picrotoxin on resting cerebral blood flow suggests that the GABAergic receptors are not tonically activated under physiological conditions.
在未麻醉的山羊身上评估了γ-氨基丁酸（GABA）和蝇蕈醇对脑血流量的影响。在大脑外血管远端闭塞和血栓形成后，通过长期植入上颌内动脉的电磁流量探头连续测量脑血流量。将GABA（1 - 100微克）直接注入脑循环会使脑血流量呈剂量依赖性增加，且无伴随的全身效应。蝇蕈醇在低10倍的剂量下模拟了GABA的作用。将印防己毒素（1 - 3毫克）注入上颌内动脉不会显著改变脑血流量，但会以剂量依赖性方式抑制GABA诱导的血管舒张。分别用普萘洛尔或阿托品选择性阻断β-肾上腺素能或毒蕈碱胆碱能受体，不会改变脑血管对GABA能激动剂的反应。这些结果表明，GABA通过作用于脑血管中的特定受体位点来增加总脑血流量。印防己毒素对静息脑血流量无影响，这表明在生理条件下GABA能受体不会被持续激活。
