摘要
Effects of hexametazidine [1,4-di(2,3,4-trimethoxybenzyl)piperazine] on the physiological properties of guinea-pig papillary muscles were investigated. Hexametazidine possesses a concentration-dependent negative inotropic effect (IC_(50)=81.8±16.9μmol/L).The effect of hexametazidine(30.8μmol/L)was antago- nized completely by increasing the concentration of Ca^(2+)from 1.8 to 5.4mmol/L. Hexametazidine(30.8μmol/L)increased the threshold concentration of adrenaline for inducing the automaticity of the muscles from 3.95±1.80 to 6.67±4.84μmol/L (P<0.05).It prolonged the functional refractory period from 218±14 to 254±20ms (P<0.05)at the concentration of 61.6μmol/L.Hexametazidine(6.2μmol/L)antago- nized the positive inotropic effect of isoprenaline competitively and of histamine non-competitively(pA 2 and pD2′ values were 5.45 and 4.13, respectively).
Effects of hexametazidine [1,4-di（2,3,4-trimethoxybenzyl）piperazine]on the physiological properties of guinea-pig papillary muscles were investigated.Hexametazidine possesses a concentration-dependent negative inotropic effect(IC<sub>50</sub>=81.8±16.9μmol/L).The effect of hexametazidine（30.8μmol/L）was antago-nized completely by increasing the concentration of Ca<sup>2+</sup>from 1.8 to 5.4mmol/L.Hexametazidine（30.8μmol/L）increased the threshold concentration of adrenalinefor inducing the automaticity of the muscles from 3.95±1.80 to 6.67±4.84μmol/L（P<0.05）.It prolonged the functional refractory period from 218±14 to 254±20ms（P<0.05）at the concentration of 61.6μmol/L.Hexametazidine（6.2μmol/L）antago-nized the positive inotropic effect of isoprenaline competitively and ofhistamine non-competitively（pA 2 and pD2′ values were 5.45 and 4.13,respectively）.
