Carbon disulphide induced sensitivity changes of rat anococcygeus muscle to noradrenaline (NA)

The sensitivity of rat anococcygeus muscle to noradrenaline (NA) was reduced following carbon disulphide (CS2) pretreatment. Preparations incubated in excess Ca++ (4.2 mmol.L-1) or Zero Ca++ (0.0 mmol.L-1) media showed decrease in sensitivity to NA. Reserpinization failed to induce supersensitivity to NA in any Mg++ concentration in the media. Reserpinized tissue in Mg++ free media with EDTA showed increased sensitivity while decreased sensitivity and maximum response to NA in Mg++ (1.2 mmol.L-1) and excess Mg++ (3.6m mol.L-1) concentration of the medium. In the presence of EDTA, the inhibition observed with CS2 in excess Mg++ (3.6m mol.L-1) medium was comparatively much less in both non-reserpinized and reserpinized preparations. In normal Ca++ and its deficient medium decrease in sensitivity to CS2 and the relevant maximum response to NA were observed. In excess Ca++, the CS2 effect depressed corresponding to its maximal response to NA. Thus CS2 may be inhibiting responses to NA by interfering with Ca++ utilization.