Conde M V, Marín J, Salaíces M, Marco E J, Gómez B, Lluch S
Am J Physiol. 1978 Aug;235(2):H131-5. doi: 10.1152/ajpheart.1978.235.2.H131.
The effects of field electrical stimulation on the contractile response of the isolated middle cerebral artery of the goat were evaluated before and after the use of experimental procedures designed to test the adrenergic component involved. Supramaximal stimuli produced frequency-dependent increases in tension. This response was significantly reduced by phentolamine (10(-6) M), tetrodotoxin (3 X 10(-6) M), and bretylium (5 X 10(-5) M), but not by cocaine (10(-6) M). Arterial segments from goats pretreated with reserpine and from goats in which both superior cervical sympathetic ganglia had been removed 12 days prior to the experiment also showed a significant decrease in the contraction elicited by electrical stimulation. The norepinephrine concentration of the arteries of the circle of Willis from control goats was 2.10 microgram per gram of tissue. Reserpine or gangliectomy reduced the catecholamine content to undetectable levels. It is likely that a major part of the contractile response of cerebral arteries to electrical stimulation is due to release of endogenous norepinephrine which in turn activates the alpha-adrenergic receptors.
在使用旨在测试所涉及的肾上腺素能成分的实验程序之前和之后，评估了场电刺激对山羊离体大脑中动脉收缩反应的影响。超最大刺激产生了频率依赖性的张力增加。酚妥拉明（10⁻⁶ M）、河豚毒素（3×10⁻⁶ M）和溴苄铵（5×10⁻⁵ M）可显著降低这种反应，但可卡因（10⁻⁶ M）则无此作用。用利血平预处理的山羊以及在实验前12天切除双侧颈上交感神经节的山羊的动脉段，电刺激引起的收缩也显著降低。对照山羊 Willis 环动脉的去甲肾上腺素浓度为每克组织2.10微克。利血平或神经节切除将儿茶酚胺含量降低到无法检测的水平。大脑动脉对电刺激的收缩反应很可能主要是由于内源性去甲肾上腺素的释放，而去甲肾上腺素又反过来激活α-肾上腺素能受体。
