ANTAGONISM BY NALOXONE OF NARCOTIC-INDUCED RESPIRATORY DEPRESSION AND ANALGESIA

  • 1 January 1978
    • journal article
    • research article
    • Vol. 207  (2) , 494-503
Abstract
Receptor mechanisms for narcotic-induced respiratory depression and analgesia in mice were compared by apparent pA2 [effective concentration of agonist to antagonist] values of morphine-naloxone, levorphanol-naloxone and pentazocine-naloxone. The similarity of apparent pA2 values of the three compounds for respiratory depression suggests that morphine, levorphanol and pentazocine may interact with similar receptors to produce this effect. Significant differences between apparent pA2 values of pentazocine-naloxone and morphine-naloxone or levorphanol-naloxone for analgesia suggest that narcotic and narcotic-antagonist analgesics appear to interact with receptors in different manners. Significant differences between apparent pA2 values for respiratory depression and analgesia suggest that these 2 effects of the narcotic drugs are mediated by different receptor interactions.