Contractile property of skeletal muscle after dicrotophos exposure in rats

Abstract

Objective: To investigate the contractile characteristics of skeletal muscles after dicrotophos exposure. Methods: A preliminary study was performed to determine the effective dose of dicrotophos that causes at least 30 % reduction in red blood cell cholinesterase activity. The rats were injected with dicrotophos daily at LD6.25, LD12.5 and LD25 doses for 5 weeks. It was found that the LD12.5 dose caused the effect, starting at the 4th week of injection. Therefore, this dose was injected into the rats before examining the isometric twitch characteristics of gastrocnemius muscle and cholinesterase activity in red blood cells and muscle homogenates. Results: Significant decreases in peak tension and time to peak tension were observed in rats exposed to this dose of dicrotophos. These decreases agreed with cholinesterase activity in RBC and muscle homogenates. Conclusion: Dicrotophos exposure in rats caused decreased contractile activity providing direct evidence implying the muscle weakness often found in humans.