Inhibitory effect of lead on 5-hydroxytryptamine induced contractions of isolated ileum of rat

• Published in: Agents and Actions Vol. 33; no. 3-4; pp. 337 - 342
• Main Authors: Gandhi, D N, Venkatakrishna-Bhatt, H
• Format: Journal Article
• Language: English
• Published: Switzerland 01-07-1991
• Subjects: Animals; Calcium - metabolism; Edetic Acid - pharmacology; Ileum - drug effects; Ileum - metabolism; Lead - pharmacology; Male; Methysergide - pharmacology; Muscle Contraction - drug effects; Muscle, Smooth - drug effects; Permeability; Phentolamine - pharmacology; Rats; Rats, Inbred Strains; Serotonin - pharmacology; Serotonin Antagonists - pharmacology
• ISSN: 0065-4299; 1420-908X
• DOI: 10.1007/BF01986583

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.