CENTRALLY MEDIATED INTESTINAL STIMULATION BY MORPHINE

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  • 1 January 1977
    • journal article
    • research article
    • Vol. 202  (1) , 174-181
Abstract
The effects of intraventricularly (i.v.) administered morphine, apomorphine and epinephrine on the small intestine were studied. Adult cats were implanted chronically with extracellular, monopolar electrodes at equal intervals along the entire small intestine. A Collison cannula was placed in the left lateral cerebral ventricle. In animals that did not respond with emesis, morphine sulfate (200 .mu.g) administered i.vt. increased the incidence of spike potentials over the proximal 3/4 of the small intestine almost immediately. The response to i.vt. morphine was abolished by pretreatment with i.vt. naloxone HCl (200 .mu.g) and was not obtained after peripheral (i.p.) morphine injection at the same dose effective centrally. No change in the number of spike potentials occurred after i.vt. administration of 2 other potent emetic agents, apomorphine HCl (200 .mu.g) and epinephrine HCl (150 .mu.g), in animals that did not respond with emesis. The increased incidence of spike potentials after i.vt. morphine is probably a naloxone-sensitive, centrally mediated event not associated with activation of the central emetic mechanism.