Articles: narcotic-antagonists.
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The concept of multiple opioid receptors reconciles a large body of clinical and pharmacological data. Recent studies have shown that there are also multiple opioid binding sites. It would appear that there is considerable variability between species in both the specificity and selectivity of opioid receptors. ⋯ Already subspecies of mu, kappa, and sigma receptors are being postulated. Both pharmacological and neurochemical methods may reveal even more. Some of the newer kappa agonists differ in their pharmacology from the prototypic kappa agonist ethylketazocine.
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Subcutaneous administrations of naloxone and naltrexone have already been shown to enhance nociceptive reactions in mice. The present study was undertaken to examine the effects of N-methyl-naloxone and N-methylnaltrexone on nociception using the hot plate test (dose range: 0.3 to 30 mg kg-1s.c.). The latter compounds were selected to differentiate the central and peripheral components of hyperalgesia. ⋯ Further, N-methylnaloxone and N-methylnaltrexone were very weak in precipitating the signs of abstinence in mice rendered acutely dependent on morphine. Two factors, poorer penetration into the CNS and steric hindrance, might render the N-methylated antagonists weak. Hence, both these factors should be considered when interpreting the effects after quaternary derivatives of opioid antagonists.
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The American surgeon · Mar 1982
Case ReportsCholangiographic demonstration of relief of narcotic-induced spasm of the sphincter of Oddi.
Narcotics are known to cause spasm of the sphincter of Oddi. This spasm may be difficult to distinguish from obstruction of the distal common bile duct on operative cholangiograms in cases where narcotics are used perioperatively. A case is presented in which narcotic-induced spasm of the sphincter of Oddi, clearly demonstrated in an operative cholangiogram, is reversed by a narcotic antagonist, thereby avoiding an unnecessary common duct exploration.