| RESEARCH PAPER
|Year : 1987 | Volume
| Issue : 2 | Page : 108-116
Effect of chronic lead toxicity on the sensitivity of anococcygeus muscle of rat
RS Shah, AN Jain, Devan Aruna, RK Goyal
1. The present investigation was undertaken to study the effects of chronic lead toxicity on the sensitivity of rat anococcygeus muscle to various agonists.
2. Treatment of rats with lead acetate (6.5 mg/kg/day, i,p. for 21 days) resulted in significant elevation of blood level and ( -aminolevulnic acid in urine ( ( -ALA-U).
3. The anococcygeus muscle isolated from lead treated rats exhibited supersensitivity to noradrenaline, dopamine, carbachol and 5-hydroxytryptamine.
4. Deprivation of Cat-t from the bathing medium did not alter significantly the responses to these agonists, however the supersensitivity was completely abolished in anococcy-geus muscle preparations obtained from lead treated animals.
5. The supersensitivity to these agonists was maintained in lead treated preparations bathed in medium containing high Ca++.
6. Ca Cl2 produced a dose depeodent contraction in the presence of sub-threshold dose of various agonists. These responses were significantly increased in lead treated preparations.
7. Our data indicate that chronic lead toxicity produces supersensitivity to various agonists in rat anococcygeus muscle.The mechanism of this supersensitivity may be related to an increased availability of calcium and/or increased sensitivity to the calcium of the tissues.
R S Shah
Source of Support: None, Conflict of Interest: None