The sigma ligand, igmesine, inhibits cholera toxin and Escherichia coli enterotoxin induced jejunal secretion in the rat.
BACKGROUND
Cholera toxin, and Escherichia coli heat labile (LT) and heat stable (STa) enterotoxins induce small intestinal secretion in part by activating enteric nerves. Igmesine is a novel sigma receptor ligand that inhibits neurally mediated secretion.


OBJECTIVE
To assess the antisecretory potential of igmesine in cholera toxin, LT, and STa induced water and electrolyte secretion using an in vivo rat model of jejunal perfusion.


METHODS
After pretreatment with igmesine, 0.03-10 mg/kg intravenously, jejunal segments of anaesthetised, adult male Wistar rats were incubated with cholera toxin (25 microg), LT (25 microg), or saline. Jejunal perfusion with a plasma electrolyte solution containing a non-absorbable marker was undertaken. In some cases 200 microg/l STa was added to the perfusate. After equilibration, net water and electrolyte movement was determined. In additional experiments rats received igmesine, intravenously or intrajejunally, after exposure to cholera toxin.


RESULTS
Cholera toxin induced net water secretion was inhibited by 1 mg/kg igmesine (median -120 versus -31 microl/min/g, p<0.001). LT and STa induced secretion were also inhibited by 1 mg/kg igmesine (-90 versus -56, p<0.03; and -76 versus -29, p<0.01, respectively). Igmesine reduced established cholera toxin induced secretion.


CONCLUSIONS
The sigma ligand, igmesine, inhibits neurally mediated enterotoxigenic secretion. Its ability to inhibit established secretion makes it an agent with therapeutic potential.
Turvill
J L
JL
Digestive Diseases Research Centre, St Bartholomew's and The Royal London School of Medicine and Dentistry, Turner Street, London E1 2AD, UK.
Kasapidis
P
P
Farthing
M J
MJ
D000818:Animals; D000992:Antitoxins / Q000494:pharmacology*; D001427:Bacterial Toxins / Q000037:antagonists & inhibitors* / Q000494:pharmacology; D001834:Body Water / Q000378:metabolism; D002772:Cholera Toxin / Q000037:antagonists & inhibitors* / Q000494:pharmacology; D002934:Cinnamates / Q000494:pharmacology*; D003521:Cyclopropanes / Q000494:pharmacology*; D004573:Electrolytes / Q000378:metabolism; D004768:Enterotoxins / Q000037:antagonists & inhibitors* / Q000494:pharmacology; D029968:Escherichia coli Proteins; D007583:Jejunum / Q000187:drug effects* / Q000378:metabolism; D008024:Ligands; D008297:Male; D051381:Rats; D017208:Rats, Wistar
D000992:Antitoxins; D001427:Bacterial Toxins; D002934:Cinnamates; D003521:Cyclopropanes; D004573:Electrolytes; D004768:Enterotoxins; D029968:Escherichia coli Proteins; D008024:Ligands; C034151:heat stable toxin (E coli); D002772:Cholera Toxin; C065310:igmesine