山莨菪碱对A_(23187)诱导的血小板内游离钙升高的影响

EFFECTS OF ANISODAMINE ON [Ca^(++) ]i RISES EVOKED BY A_(23187) IN HUMAN PLATELETS

应用Quin-2测得含有1mmol/L CaCl_2和2mmol/L EGTA的介质中血小板内静息游离钙浓度为52.1±5.2nmol/L和28.4±5.1nmol/L。A_(23187)诱导的血小板在有钙或无钙时胞浆游离钙增加的峰值分别为145.8±30.8nmol/L和34.4±2.4nmol/L,山莨菪碱对静息游离钙和无外源钙时A_(23187)刺激的游离钙无影响,山莨菪碱(100μmol/L,25μmol/L)、维拉帕米(10μmol/L)分别降低有外源钙时A_(23187)诱导的游离钙峰值38%、34%、25%。山莨菪碱具有钙拮抗作用。

Intracellular [Ca+ + ]i was examined using Quin-2. Resting [Ca+ + ]i in platelets loaded with Quin-2 in media containing either 1 mmol/L CaCl2. or 2 mmol/L EGTA was 52.1±5.2nmol/L, 28.4+5.1 nmol/L, respectively. The concentration of external calcium appears to play an important role in cytosolic Cat++ hemeostasis in platelets. Stimulation with A2 3187( 25nmol/L ) caused [Ca++]i to peak at 145±30.8 nmol/L in the presense of extracellular 1mmol/L CaCl2 and 34.4±2.4 nmol/L after addition of 2 mmol/L EGTA. These data suggested that the most of this rise results from calcium entry across the plasma membrane, with a small contribution to the discharge of intracellular pool of Ca++. Anisodamine ( 100μmol/L ) had no effects on resting [Ca + + ]i and A23187-evoked [Ca++]i level in the absence of CaCl2, Anisodamine ( 100μmol/L, 25μmol/L), verapamil ( 10μmol/L ) decreased the A23187 -evoked [Ca++ ]i rises in the presence of CaCl2 by 38%, 34%, 25%, respectively. These results provided a mechanism for the calcium antagonistic effects of Anisodamine.