The effects of 2-[p-(Dimethylamino)styryl] pyridine methiodide(DSPM)on slow response action potential(SRAP)and slow inward current(Isi) of guinea pig papillary muscles were studied by intracellular microelectrodes and...The effects of 2-[p-(Dimethylamino)styryl] pyridine methiodide(DSPM)on slow response action potential(SRAP)and slow inward current(Isi) of guinea pig papillary muscles were studied by intracellular microelectrodes and voltage clamp techniques.The APA and V_(max) of SRAP induced by high K￣+were decreased after 50 min of perfusion with DSPM solu- tion. Isi was suppressed from a peak value of8.8± 1.6μA to 5.7± 1.8μA, The results indicated that DSPM has a selective blocking effect on calcium channel.展开更多
Objective To study the antineoplastic effect of the calcium channel blocker verapamil and 5-fluorouracil intraperitoneal chemotherapy onhepatocarcinoma-bearing rats, and examine the action between calcium channel bloc...Objective To study the antineoplastic effect of the calcium channel blocker verapamil and 5-fluorouracil intraperitoneal chemotherapy onhepatocarcinoma-bearing rats, and examine the action between calcium channel blockers and cytotoxic drugs.Methods We adopted the method of subcapsular implantation of carcinoma tissues of walker-256 in the left liver lobe as a model of livercarcinoma-bearing rats. All experimental animals were divided into four groups. On the sixth day post implantation, in group A (controlgroup) 6 ml of saline was injected intraperitoneally once a day for 3 days. In group B (single chemotherapy group) 6 ml of 5-Fu 75 mg/kg was injected intraperitoneally once a day for 3 days. In group C (combination of treatment group) both 5-Fu (75 mg/kg) and verapamil(25 mg/kg) were administered simultaneously as in A and B. In group D (simple verapamil group) only 6 ml of verapamil (25 mg/kg)was administered as above.Results Compared with groups A, B and D, The volume of cancer and the contents of liver cancer DNA and protein were significantlyreduced. The rates of inhibiting cancer (89.9% in group C and 35.4% in group B) were significantly increased in group C. Group C hadsignificantly long survival time compared to groups A, B and D ( P < 0.05) . By light microscopy, a number of focal necroses were foundin cancer tissue in group C.Conclusion Calcium channel blockers can enhance the antineoplastic effect of 5-Fu intraperitoneal chemotherapy to liver cancer ; Theuse of verapamil can not increase the toxicity of 5-Fu.展开更多
The effects of berbamine, an alkaloid of dibenzylisoquinoline, on PAF produc tion in human neutrophils and on platelet aggregation induced by PAF were studied and compared with those of the calcium antagonist verapam...The effects of berbamine, an alkaloid of dibenzylisoquinoline, on PAF produc tion in human neutrophils and on platelet aggregation induced by PAF were studied and compared with those of the calcium antagonist verapamil. Preincubation with berbamine (50 mmol / L, 100 mmol / L) or verapamil (10 mmol / L, 100 mmol / L) was shown to significantly inhibit A 23187 stimulated PAF synthesis. Berbamine and verapamil were found to inhibit platelet aggregation induced by PAF 70 pmol / L in a dose dependent manner. These results suggest that the inhibitory effects of berbamine and verapamil on A 23187 stimulated PAF synthesis in human neutrophils and PAF induced platelet aggregation are possibly brought about by inhibiting cellular calcium influx.展开更多
文摘The effects of 2-[p-(Dimethylamino)styryl] pyridine methiodide(DSPM)on slow response action potential(SRAP)and slow inward current(Isi) of guinea pig papillary muscles were studied by intracellular microelectrodes and voltage clamp techniques.The APA and V_(max) of SRAP induced by high K￣+were decreased after 50 min of perfusion with DSPM solu- tion. Isi was suppressed from a peak value of8.8± 1.6μA to 5.7± 1.8μA, The results indicated that DSPM has a selective blocking effect on calcium channel.
文摘Objective To study the antineoplastic effect of the calcium channel blocker verapamil and 5-fluorouracil intraperitoneal chemotherapy onhepatocarcinoma-bearing rats, and examine the action between calcium channel blockers and cytotoxic drugs.Methods We adopted the method of subcapsular implantation of carcinoma tissues of walker-256 in the left liver lobe as a model of livercarcinoma-bearing rats. All experimental animals were divided into four groups. On the sixth day post implantation, in group A (controlgroup) 6 ml of saline was injected intraperitoneally once a day for 3 days. In group B (single chemotherapy group) 6 ml of 5-Fu 75 mg/kg was injected intraperitoneally once a day for 3 days. In group C (combination of treatment group) both 5-Fu (75 mg/kg) and verapamil(25 mg/kg) were administered simultaneously as in A and B. In group D (simple verapamil group) only 6 ml of verapamil (25 mg/kg)was administered as above.Results Compared with groups A, B and D, The volume of cancer and the contents of liver cancer DNA and protein were significantlyreduced. The rates of inhibiting cancer (89.9% in group C and 35.4% in group B) were significantly increased in group C. Group C hadsignificantly long survival time compared to groups A, B and D ( P < 0.05) . By light microscopy, a number of focal necroses were foundin cancer tissue in group C.Conclusion Calcium channel blockers can enhance the antineoplastic effect of 5-Fu intraperitoneal chemotherapy to liver cancer ; Theuse of verapamil can not increase the toxicity of 5-Fu.
文摘The effects of berbamine, an alkaloid of dibenzylisoquinoline, on PAF produc tion in human neutrophils and on platelet aggregation induced by PAF were studied and compared with those of the calcium antagonist verapamil. Preincubation with berbamine (50 mmol / L, 100 mmol / L) or verapamil (10 mmol / L, 100 mmol / L) was shown to significantly inhibit A 23187 stimulated PAF synthesis. Berbamine and verapamil were found to inhibit platelet aggregation induced by PAF 70 pmol / L in a dose dependent manner. These results suggest that the inhibitory effects of berbamine and verapamil on A 23187 stimulated PAF synthesis in human neutrophils and PAF induced platelet aggregation are possibly brought about by inhibiting cellular calcium influx.
