Sarin muscle cells

Fleisher reported that both sarin and VX increased the sensitivity of the isolated frog s rectus abdominis to external application of acetylcholine and at the same time decreased the activity of cholinesterase in the external surfaces of the muscle cells. Sarin at 5 x 10-7 M reduced the threshold concentration of acetylcholine for inducing contraction of the muscle to 8% of that required before application of sarin. The same concentration of VX reduced the threshold concentration of acetylcholine to 6.7% of that needed previously. Contemporaneously, the activity of cholinesterase in the external surfaces of the muscle cells was reduced to 8.1% and 0% of that before application of sarin and VX, respectively. Addition of 2-PAM I at 5 x 10 M to the baths in which the muscles were suspended had little effect on the activity of the enzyme in homogenates of the muscles, but restored 75% and 91%, respectively, of the activity of cholinesterase in the external surfaces of the muscles exposed to sarin and VX. At the same time, the concentration of acetylcholine required to induce contraction of the muscles was raised to 53.3% and 58.3% of the original threshold concentrations, respectively, for the muscles exposed to sarin and to VX. 

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