Altura B M, Carella A, Altura B T
Prostaglandins Med. 1980 Aug;5(2):123-30. doi: 10.1016/0161-4630(80)90099-3.
The influence of artificial buffers, Tris, HEPES and MOPS, on PGA1, B2 and F2 alpha-induced contractile responses of isolated rat aorta and portal vein was investigated. All three buffers, in 5mM concentration, when substituted for bicarbonate and phosphate anions, differentially attenuated PG-induced contractile responses; the vein responses exhibited the greater sensitivity to artificial buffer inhibition. In the presence of the artificial buffers, the PG-induced fast phase contractile components on the arterial smooth muscle were obliterated and the slow, tonic components were markedly depressed. PG contractile concentration-effect curves were shifted, differentially, to the right, concomitant with differential reductions in maximum tensions. Reincubation of the vascular tissues in normal Krebs-Ringer bicarbonate for 30-60 min resulted in a complete restoration of full PG-induced contractions. These results support the idea that Tris, HEPES and MOPS may interfere with the binding, translocation and utilization of calcium ions in vascular smooth muscle cells. One must be cautious regarding conclusions drawn for calcium-dependent responses obtained in smooth muscles in which Tris, HEPES or MOPS was the sole buffering agent.
研究了人工缓冲剂三羟甲基氨基甲烷（Tris）、4-（2-羟乙基）-1-哌嗪乙磺酸（HEPES）和3-（N-吗啉代）丙磺酸（MOPS）对PGA1、B2和F2α诱导的离体大鼠主动脉和门静脉收缩反应的影响。当用5mM浓度的这三种缓冲剂替代碳酸氢根和磷酸根阴离子时，它们对PG诱导的收缩反应有不同程度的减弱作用；静脉反应对人工缓冲剂抑制的敏感性更高。在人工缓冲剂存在的情况下，PG诱导的动脉平滑肌快速相收缩成分消失，而缓慢的紧张性成分明显受到抑制。PG收缩浓度-效应曲线不同程度地向右移动，同时最大张力也有不同程度的降低。将血管组织在正常的 Krebs-Ringer 碳酸氢盐中再孵育30 - 60分钟，可使PG诱导的完全收缩反应完全恢复。这些结果支持这样一种观点，即Tris、HEPES和MOPS可能会干扰血管平滑肌细胞中钙离子的结合、转运和利用。对于在以Tris、HEPES或MOPS作为唯一缓冲剂的平滑肌中获得的钙依赖性反应得出的结论，必须谨慎对待。
