Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0278080 (physical dependence)
 1,658 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Four hours after the acute administration of L-tryptophan (75 mg/kg) to either, nontolerant or morphine-tolerant mice, the antinociceptive effect of morphine was partially and significantly antagonized. Daily tryptophan administration to rats and mice during a 3-day morphine pellet implantation period increased the rates of both morphine tolerance development and development of physical dependence. The accelerating effect of tryptophan on tolerance and dependence development in mice was antagonized by pretreatment with the tryptophan hydroxylase inhibitor, p-chlorophenylalanine. Acute tryptophan administration (75 mg/kg) significantly increased mouse brain 5-hydroxytryptamine levels for at least 4 hours. Although chronic tryptophan treatment increased 5-hydroxytryptamine turnover in morphine-treated mice, no effect of chronic morphine or tryptophan treatment on the particulate tryptophan hydroxylase activity of whole mouse brain was observed. Slight increases in tryptophan hydroxylase activity were observed in the caudate-putamen and septal areas of rat brain 3 and 6 days, respectively, after s.c. morphine pellet implantation. These and previous studies from our laboratory indicate that the development of morphine tolerance and dependence can be modified by agents affecting serotonergic mechanisms.
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PMID:Influence of L-tryptophan on morphine analgesia, tolerance and physical dependence. 12 49

The effects of L-tryptophan and the major constituents of cough medicines on the antitussive effect of dihydrocodeine were examined in a comparative study with anesthetized rats. The antitussive effect of dihydrocodeine was enhanced by simultaneous administration of noscapine or methylephedrine. In rats treated with noscapine and methylephedrine together, the effect of dihydrocodeine was more markedly enhanced. Furthermore L-tryptophan reduced by half the antitussive ED50 (AtD50) of dihydrocodeine. There was no difference between the AtD50 of dihydrocodeine when administered in combination with noscapine and methylephedrine and that of dihydrocodeine when combined with noscapine and L-tryptophan. The AtD50 of noscapine and dextromethorphan was also reduced by about half when what was administered with L-tryptophan. By contrast, the liability with respect to physical dependence on dihydrocodeine was not enhanced by the simultaneous administration of L-tryptophan. These results suggest that L-tryptophan can be considered to be a useful constituent of antitussive preparations.
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PMID:Effects of L-tryptophan on the effects of antitussives. 238 57

Serotonin turnover was measured in mouse brain by means of the conversion of radioactivity from labeled tryptophan into serotonin. Animals with a high degree of tolerance to and physical dependence on morphine did not differ from control mice.
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PMID:Narcotic tolerance and dependence: lack of relationship with serotonin turnover in the brain. 554 76