Erspamer G F, Severini C, Erspamer V, Melchiorri P
Institute of Medical Pharmacology III, University of Rome La Sapienza, Italy.
Neuropharmacology. 1989 Apr;28(4):319-28. doi: 10.1016/0028-3908(89)90025-7.
Semi-purified extracts of the skin of the Australian myobatrachid frog Pseudophryne coriacea (PS)displayed striking, reversible and, in part, dose-dependent effects on the systemic blood pressure of the rat and other experimental animals, as well as on the rat heart. The blood pressure response in the rat consisted typically in an abrupt, short-lasting fall, followed by a conspicuous, more persistent rise. The fall in pressure was abolished by atropine and potentiated by physostigmine, indicating a cholinergic mechanism; rise was abolished by prazosin and guanethidine, suggesting a release of catecholamines from adrenergic nerve terminals in the vasculature. Tachyphylaxis was the obvious result of exhaustion of stores of catecholamines. On the heart, as shown in the electrocardiographic tracings, PS produced a variety of rhythm disorders, attributable both to the release of aminergic transmitters and to a direct effect on the myocardium. Whereas the pressure and electrocardiographic responses were virtually unaffected by calcium channel antagonists and agonists, all the effects of PS were sharply reduced or completely abolished by the sodium channel blocker tetrodotoxin. This suggests that activation of sodium channels may play a role in the mechanism of action of PS. However, the exact nature of ionic flux(es)influenced by the extract of frog skin remains to be established.
澳大利亚沼蟾科蛙类——粗皮伪蛙（Pseudophryne coriacea，PS）皮肤的半纯化提取物，对大鼠及其他实验动物的全身血压以及大鼠心脏呈现出显著、可逆且部分呈剂量依赖性的作用。大鼠的血压反应通常先是急剧、短暂的下降，随后是明显且更持久的上升。阿托品可消除血压下降，毒扁豆碱可增强此效应，表明存在胆碱能机制；哌唑嗪和胍乙啶可消除血压上升，提示有儿茶酚胺从血管系统中的肾上腺素能神经末梢释放出来。快速耐受性是儿茶酚胺储备耗竭的明显结果。在心脏方面，如心电图记录所示，PS会引发多种心律失常，这既归因于胺能递质的释放，也归因于对心肌的直接作用。尽管压力和心电图反应实际上不受钙通道拮抗剂和激动剂的影响，但PS的所有效应都被钠通道阻滞剂河豚毒素大幅降低或完全消除。这表明钠通道的激活可能在PS的作用机制中发挥作用。然而，蛙皮提取物所影响的离子通量的确切性质仍有待确定。
