Harris R A, Hanrahan J W
Department of Physiology, McGill University, Montreal, Quebec, Canada.
Am J Physiol. 1993 Sep;265(3 Pt 1):C781-91. doi: 10.1152/ajpcell.1993.265.3.C781.
We have studied the cytosolic free Ca2+ concentration ([Ca2+]i) response to histamine and other inflammatory mediators in a cystic fibrosis tracheal epithelial cell line (CF/T43) using digital fluorescence imaging. Brief pulses of histamine increased [Ca2+]i in a concentration-dependent manner with threshold, half-maximal, and maximal responses at approximately 5 microM, 120 microM, and 10 mM, respectively. The calcium response to sustained histamine exposure was markedly biphasic, consisting of an early peak (to approximately 2.4 microM [Ca2+]i) followed by a smaller second peak that lasted 45-60 s. Neither peak was directly dependent on Ca2+ influx. In contrast, stimulation with bradykinin gave a single peak followed by a smooth decay back to baseline levels. Sustained perfusion with histamine did not affect the bradykinin response, which is known to be mediated by inositol 1,4,5-trisphosphate (IP3). The H1-type histamine receptor blockers mepyramine, diphenhydramine, and (+)-chlorpheniramine were potent antagonists of the histamine response. Diphenhydramine was also a weak agonist at high concentrations (> or = 1 mM) and gave a biphasic response similar to that with histamine. The H2-type receptor blocker cimetidine and the H3-type receptor blocker thioperamide had no effect. Indomethacin failed to inhibit the second phase of the histamine-stimulated [Ca2+]i response, suggesting that the second [Ca2+]i peak is not due to secondary production of prostaglandins. Neomycin, which inhibits IP3 production, completely abolished the [Ca2+]i response to bradykinin stimulation but did not affect the second phase of the histamine response. The biphasic nature of the histamine response, the insensitivity of the second [Ca2+]i peak to neomycin, and the independence of bradykinin and histamine responses suggest that histamine may modulate [Ca2+]i through multiple IP3 and non-IP3 pathways.
我们使用数字荧光成像技术研究了囊性纤维化气管上皮细胞系（CF/T43）中胞质游离钙离子浓度（[Ca2+]i）对组胺及其他炎症介质的反应。组胺的短暂脉冲以浓度依赖的方式增加[Ca2+]i，其阈值、半最大反应和最大反应浓度分别约为5 microM、120 microM和10 mM。对持续组胺暴露的钙反应明显呈双相性，包括一个早期峰值（至约2.4 microM [Ca2+]i），随后是一个较小的第二个峰值，持续45 - 60秒。两个峰值均不直接依赖于钙离子内流。相比之下，缓激肽刺激产生一个单一峰值，随后平稳衰减至基线水平。持续用组胺灌注不影响缓激肽反应，已知缓激肽反应是由肌醇1,4,5 - 三磷酸（IP3）介导的。H1型组胺受体阻滞剂美吡拉敏、苯海拉明和（+） - 氯苯那敏是组胺反应的有效拮抗剂。苯海拉明在高浓度（≥1 mM）时也是一种弱激动剂，并产生与组胺相似的双相反应。H2型受体阻滞剂西咪替丁和H3型受体阻滞剂硫代哌啶没有作用。吲哚美辛未能抑制组胺刺激的[Ca2+]i反应的第二阶段，表明第二个[Ca2+]i峰值不是由于前列腺素的二次产生。抑制IP3产生的新霉素完全消除了对缓激肽刺激的[Ca2+]i反应，但不影响组胺反应的第二阶段。组胺反应的双相性质、第二个[Ca2+]i峰值对新霉素的不敏感性以及缓激肽和组胺反应的独立性表明，组胺可能通过多种IP3和非IP3途径调节[Ca2+]i。
