Suppression of castor oil-induced diarrhoea by alpha 2-adrenoceptor agonists.
The effects of systemic administration of alpha 2-adrenoceptor agonists on migrating myoelectric complexes and castor oil-induced diarrhoea of the small intestine were studied in conscious rats. Castor oil (1 mg/kg, intraduodenally) disrupted the migrating myoelectric complexes and induced irregular spiking activity with sporadic bursts of myoelectric activity. This change of motility pattern was present concomitant with diarrhoea 1-2 h after instillation of castor oil and during the whole period of diarrhoea. Pre-treatment with clonidine (5-10 micrograms/kg i.v.) or oxymetazoline (5.6-11.2 micrograms/kg i.v.), a peripherally active alpha 2-agonist, inhibited the irregular spiking induced by castor oil and no diarrhoea occurred during the experimental period of 6 h. Thus, the antidiarrhoeal action of peripherally acting alpha 2-adrenoceptor agonists such as oxymetazoline, may be of clinical value in the treatment of diarrhoea.
Department of Pharmacology, Karolinska Institutet, Stockholm, Sweden.
M
M
Thollander
P M
PM
Hellström
T H
TH
Svensson
D000316:Adrenergic alpha-Agonists / Q000494:pharmacology / Q000627:therapeutic use*; D000818:Animals; D002368:Castor Oil; D003000:Clonidine / Q000008:administration & dosage / Q000494:pharmacology / Q000627:therapeutic use; D003967:Diarrhea / Q000139:chemically induced / Q000517:prevention & control*; D004576:Electromyography / Q000187:drug effects; D005769:Gastrointestinal Motility / Q000187:drug effects*; D007421:Intestine, Small / Q000502:physiology; D008297:Male; D010109:Oxymetazoline / Q000008:administration & dosage / Q000494:pharmacology / Q000627:therapeutic use; D051381:Rats; D011919:Rats, Inbred Strains
D000316:Adrenergic alpha-Agonists; D002368:Castor Oil; D010109:Oxymetazoline; D003000:Clonidine