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Enterotoxin Escherichia coli STa activates a nitric oxide‐dependent myenteric plexus secretory reflex in the rat ileum.
Author(s) -
Rolfe V,
Levin R J
Publication year - 1994
Publication title -
the journal of physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.802
H-Index - 240
eISSN - 1469-7793
pISSN - 0022-3751
DOI - 10.1113/jphysiol.1994.sp020091
Subject(s) - carbachol , tetrodotoxin , nitric oxide , chemistry , ileum , secretion , in vivo , capsaicin , reflex , endocrinology , medicine , pharmacology , biology , receptor , biochemistry , microbiology and biotechnology
1. Mucosally added enterotoxin Escherichia coli STa increased the electrogenic Cl‐ secretion measured as the short‐circuit current (Isc) across isolated muscle‐stripped and muscle‐unstripped rat mid‐ilea incubated in vitro. 2. Pretreatment with serosal L‐NAME (N omega‐nitro‐L‐arginine methyl ester) or tetrodotoxin (TTX) significantly reduced the maximum Isc and the duration of action of STa in the unstripped but not stripped ilea. D‐NAME (serosal), indomethacin or 5‐hydroxy‐tryptamine‐desensitization was ineffective on STa‐induced Isc in either stripped or unstripped ilea. 3. Serosal capsaicin reduced the maximum Isc of STa and its duration of action in unstripped ilea. 4. L‐Arginine induced a significantly larger increase in the Isc across unstripped ilea than across stripped ilea; this could be significantly reduced by serosal L‐NAME or TTX, although these were ineffective in stripped ilea. 5. Pretreatment of anaesthetized rats with I.P. L‐NAME suppressed the fluid secretion induced by luminal STa in ilea in vivo but had no effect on that induced by luminal carbachol. 6. Mucosal STa increased electrogenic Cl‐ secretion across intact rat ileum in vitro by activating a capsaicin‐sensitive, nitric oxide‐dependent myenteric plexus‐mediated secretory reflex. The suppression by L‐NAME of STa induced ileal fluid secretion in vivo probably involves the inhibition of this reflex.