Couto A S, Moraes-Santos T, Azevedo A D, Almeida A P, Freire-Maia L
Departamentos de Farmacologia, Universidade Federal de Minas Gerais, Brazil.
Toxicon. 1992 Mar;30(3):339-43. doi: 10.1016/0041-0101(92)90874-5.
By using a pair of silver/silver-chloride electrodes it was possible to record, simultaneously, the atrial electrogram and the atrial contractile force of rat atria, in an organ bath, containing Krebs-Ringer solution (30 degrees C, pH 7.4, bubbled with 95% O2 and 5% CO2). Addition of toxin Ts-gamma, purified from Tityus serrulatus scorpion venom, into the bath (1 microgram/ml), evoked complex effects characterized by an initial reduction of both rate and contractile force, followed by increase of force and reduction of rate and finally by reduction of both rate and force. The increase of contractile force was prevented by metoprolol and is, therefore, adrenergic in nature. The reduction of rate was concomitant with changes in the atrial electrogram in which a positive P wave was replaced by a diphasic P wave, while the positive Ta wave was depressed. Experiments with tetrodotoxin, atropine and physostigmine indicate that these effects are due to the release of acetylcholine from vagal endings.
通过使用一对银/氯化银电极，能够在含有 Krebs - Ringer 溶液（30 摄氏度，pH 7.4，用 95%氧气和 5%二氧化碳鼓泡）的器官浴中同时记录大鼠心房的心电图和心房收缩力。向浴液中添加从锯齿脂鲤蝎毒液中纯化得到的毒素 Ts -γ（1 微克/毫升）会引发复杂的效应，其特征是最初心率和收缩力均降低，随后力量增加、心率降低，最后心率和力量都降低。美托洛尔可阻止收缩力的增加，因此这种增加本质上是肾上腺素能的。心率降低与心房心电图的变化同时出现，其中正向 P 波被双相 P 波取代，而正向 Ta 波降低。用河豚毒素、阿托品和毒扁豆碱进行的实验表明，这些效应是由于迷走神经末梢释放乙酰胆碱所致。
