Inhibitory effect of lead on 5-hydroxytryptamine induced contractions of isolated ileum of rat.
The present study examined the effects of lead (Pb) on the 5-hydroxytryptamine (5-HT) contracture and calcium (Ca++) kinetics of ileum of rat. Isolated ileum preparations incubated in excess Ca++ (2.8 mM) or in Ca++ free Tyrode solution showed decrease in sensitivity to 5-HT. The inhibitory action of Pb reduced the sensitivity and decrease maximum responses to 5-HT in any Mg++ concentration of the medium. In the normal Ca++ and its deficient medium deterioration in sensitivity to Pb and the relevant maximum response to 5-HT were observed. In excess Ca++, the Pb effect depressed corresponding to its maximal response to 5-HT. The presence of EDTA depressed the Pb effect irrespective of the Ca++ influence on the receptors. Thus Pb may be inhibiting responses to 5-HT by interfering Ca++ utilization.
Gandhi
D N
DN
Department of Neurobehavioural Toxicology, National Institute of Occupational Health, Gujarat, India.
Venkatakrishna-Bhatt
H
H
D000818:Animals; D002118:Calcium / Q000378:metabolism; D004492:Edetic Acid / Q000494:pharmacology; D007082:Ileum / Q000187:drug effects / Q000378:metabolism; D007854:Lead / Q000494:pharmacology*; D008297:Male; D008784:Methysergide / Q000494:pharmacology; D009119:Muscle Contraction / Q000187:drug effects; D009130:Muscle, Smooth / Q000187:drug effects*; D010539:Permeability; D010646:Phentolamine / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D012701:Serotonin / Q000494:pharmacology*; D012702:Serotonin Antagonists / Q000494:pharmacology*
D012702:Serotonin Antagonists; D007854:Lead; D012701:Serotonin; D004492:Edetic Acid; D002118:Calcium; D008784:Methysergide; D010646:Phentolamine