الفهرس 
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Abstract
The present study was the first attempt to study the effect of different aflatoxin analogs; AFB1, AFG1 and AFG2, on isolated preparations, as well as, to evaluate the protective role of vitamin C and B, singly and in combination, against their toxicity. The heart was prepared in pithed frog Normal activity was recorded, then the toxin was injected intramuscullary at a dose of (0.001 mg/frog), and finally records were taken at 15, 30, 45 and 60 minutes following injection. To evaluate the protective effect of vitamin C & B, they were injected for 4 consuctive days at doses of vitamin C (10 mg/kg b. wt.), vitamin B (3.6 mg/kg b. wt.), and mixture (vit C=5 mg/kg b. wt. + vit B=1.8 mg/kg b. wt.) before application of toxins and recording. To study the physiological properties of the skeletal muscle, the gastrocnemius muscle was separared and hinged to kymograph. Normal actvity was recorded, then the toxin was added at a concentration of 0.001 mg/frog, with or without vitamins and finally records were taken at 15, 30, 45 and 60 minutes. Concentrations of vitamins for the skeletal muscle were 10 mg/muscle of vitamin C, 3.6 mg/muscle of Vitamin B and 5 mg/muscle of vitamin C + 1.8 mg/muscle of vitamin B. Control preparations were treated with the frog Ringer?s solution. The results showed that acute treatment with AFB1 causes a significant decrease on the heart rate and twitch force of the myocardium while less potent effects were resulted on the acute treatment with AFG1 and AFG2 in decreasing order.whereas incubation of the gastrocnemius muscle with AFB1 and AFG1 showed a significant increase of the twitch force with a significant elongation of its duration on the contrary, AFG2 showed no significant effect on the gastrocnemius muscle. In conclusion, AFB1, AFG1 and AFG2 have an inhibiting effect on the heart and the contraction of cardiac muscle in the order of decreasing potency the direct effect of aflatoxins on the skeletal muscle was restricted to AFB1 and AfG1 , the present experiments also indicated that vitamin C and B complex, in particular their combination, are beneficial in combating the toxicity of aflatoxins in the cardiac and skeletal muscles.