The effects of chronic morphine treatment on neurotensin-induced antinociception.
Previous studies have shown that the opioid antagonist naloxone does not alter neurotensin (NT)-induced antinociception. In the present studies, tolerance to morphine in mice significantly attenuated NT-induced antinociception, but not NT-induced hypothermia. In addition, centrally administered NT inhibited naloxone-precipitated jumping in morphine-dependent mice. These results indicate complex interactions between NT-induced antinociception and opioid systems.
D000700:Analgesics / Q000037:antagonists & inhibitors*; D000818:Animals; D004361:Drug Tolerance; D006801:Humans; D008297:Male; D051379:Mice; D009020:Morphine / Q000494:pharmacology*; D009021:Morphine Dependence / Q000503:physiopathology; D009270:Naloxone / Q000494:pharmacology; D009496:Neurotensin / Q000037:antagonists & inhibitors*; D013997:Time Factors
D000700:Analgesics; D009270:Naloxone; D009496:Neurotensin; D009020:Morphine