Savino E A, Catanzaro O L
Acta Physiol Pharmacol Latinoam. 1985;35(1):119-27.
The isolated tail artery when exposed to 0.14-2.80 microM tityustoxin (a purified peptide from the venom of the scorpion Tityus serrulatus) underwent a transient contraction which was followed by a long lasting period of unresponsiveness to further additions of the toxin. Reserpine pretreatment, the addition of phentolamine, tetrodotoxin, verapamil or lowering the sodium concentration abolished the responses to the toxin. Cocaine potentiated it. Tityustoxin caused a slight leftward shift of the dose-response curves to adrenaline and norepinephrine and a large potentiation of the frequency-response curves to electrical stimulation. The latter effect was greater within the lower range of frequencies assayed, which coincide with those of the physiological discharge of sympathetic nerves. These data indicate that in the tail artery the tityustoxin acts indirectly on the smooth muscle through the release of endogenous catecholamines. Most likely, changes of the properties of the sodium channels and calcium influx are involved in this effect at the nerve endings. The potentiation of the frequency-response curves suggests that the arterial hypertension produced by the scorpion sting may result mainly from an abnormally elevated overflow of sympathetic transmitters.
分离出的尾动脉在暴露于0.14 - 2.80微摩尔/升的锯尾蝎毒素（一种从锯尾蝎毒液中纯化得到的肽）时，会经历短暂的收缩，随后是对进一步添加毒素无反应的持久阶段。利血平预处理、添加酚妥拉明、河豚毒素、维拉帕米或降低钠浓度可消除对毒素的反应。可卡因可增强这种反应。锯尾蝎毒素使肾上腺素和去甲肾上腺素的剂量 - 反应曲线略有左移，并使电刺激的频率 - 反应曲线大幅增强。后一种效应在测定的较低频率范围内更大，这与交感神经的生理放电频率一致。这些数据表明，在尾动脉中，锯尾蝎毒素通过释放内源性儿茶酚胺间接作用于平滑肌。很可能，钠通道特性的改变和钙内流参与了神经末梢的这种效应。频率 - 反应曲线的增强表明，蝎蜇引起的动脉高血压可能主要源于交感递质异常升高的溢出。
