Altered calcium-handling properties of jejunal smooth muscle from the nematode-infected rat

• Published in: Gastroenterology (New York, N.Y. 1943) Vol. 91; no. 6; p. 1462
• Main Authors: Fox-Robichaud, A E, Collins, S M
• Format: Journal Article
• Language: English
• Published: United States 01.12.1986
• Subjects: Animals; Calcium - physiology; Carbachol - pharmacology; In Vitro Techniques; Intestinal Diseases, Parasitic - metabolism; Intestinal Diseases, Parasitic - physiopathology; Jejunum - metabolism; Jejunum - physiopathology; Male; Muscle Contraction - drug effects; Muscle, Smooth - physiopathology; Nematode Infections - metabolism; Nematode Infections - physiopathology; Nippostrongylus; Nitrendipine - pharmacology; Quinuclidinyl Benzilate - metabolism; Radioligand Assay; Rats; Rats, Inbred Strains; Receptors, Muscarinic - metabolism; Serotonin - pharmacology
• DOI: 10.1016/0016-5085(86)90202-7
• ISSN: 0016-5085

We examined changes in contractility of jejunal longitudinal muscle from rats infected 8 days previously with the enteric parasite Nippostrongylus brasiliensis. In uninfected control rats, carbachol-induced contraction was maximal at 1 microM carbachol. In muscle from infected rats, there was no change in ED50 for carbachol, but contraction induced by 1 microM carbachol was increased greater than 75% over that in control rats. No significant differences were observed in muscarinic receptor binding characteristics in smooth muscle cells from control and infected rats when [3H]QNB was used as radioligand. Contraction induced by 5-hydroxytryptamine was also substantially greater in muscle from infected rats. In control rats, carbachol-induced contraction was largely independent of extracellular Ca2+, whereas in muscle from infected rats, withdrawing extracellular Ca2+ reduced contraction to below control levels. Furthermore, whereas adding nitrendipine in the presence of extracellular Ca2+ had no effect on carbachol-induced contraction in control rats, it significantly inhibited contraction in muscle from infected rats.