双波长分光光度法测定复方盐酸金霉素软膏中2主药的含量

目的:建立同时测定复方盐酸金霉素软膏中盐酸金霉素和盐酸丁卡因含量的方法。方法:采用双波长分光光度法,在311、368、387·5nm波长处测定其吸光度,并计算含量。结果:盐酸金霉素和盐酸丁卡因检测浓度的线性范围分别为9·90～29·71、5·99～17·98μg·mL-1(r=0·9999);平均回收率分别为99·37%(RSD=0·31%,n=9)、98·31%(RSD=0·23%,n=9)。结论:本方法操作简便、快速,结果准确,可用于该制剂的含量测定。     

Mechanism of the ATP-induced rise in cytosolic Ca2+ in freshly isolated smooth muscle cells from human saphenous vein

Effects of exogenous adenosine 5-triphosphate (ATP) were studied by measurements of intracellular Ca²⁺ concentration ([Ca²⁺]_i) and membrane currents in myocytes freshly isolated from the human saphenous vein. At a holding potential of –60 mV, ATP (10 M) elicited a transient inward current and increased [Ca²⁺]_i. These effects of ATP were inhibited by ,-methylene adenosine 5-triphosphate (AMPCPP, 10 M). The ATP-gated current corresponded to a non-selective cation conductance allowing Ca²⁺ entry. The ATP-induced [Ca²⁺]_i rise was abolished in Ca²⁺-free solution and was reduced to 30.1±5.5% (n=14) of the control response when ATP was applied immediately after caffeine, and to 23.7±3.8% (n=11) in the presence of thapsigargin. The Ca²⁺-induced Ca²⁺ release blocker tetracaine inhibited the rise in [Ca²⁺]_i induced by both caffeine and ATP, with apparent inhibitory constants of 70 M and 100 M, respectively. Of the ATP-induced increase in [Ca²⁺]_i 29.3±3.9% (n=8) was tetracaine resistant. It is concluded that the effects of ATP in human saphenous vein myocytes are only mediated by activation of P_2x receptor channels. The ATP-induced [Ca²⁺]_i rise is due to both Ca²⁺ entry and Ca²⁺ release activated by Ca²⁺ ions that enter the cell through P_2x receptor channels.