Amphetamine-induced analgesia does not involve brain opioids.
The intrinsic analgesic properties of amphetamine were studied in rats. Subcutaneous injection of amphetamine exerted an additive effect on morphine-induced analgesia in the hot-plate test. Amphetamine itself showed intrinsic analgesic activity in a dose-dependent manner. Administration of naloxone failed to affect the analgesia induced by amphetamine. However, injection of haloperidol totally suppressed the amphetamine-induced change in pain response latency. Both naloxone and haloperidol failed to affect the pain threshold when injected alone, but inhibited morphine-induced analgesia. It is concluded that amphetamine possesses intrinsic analgesic properties which involve catecholamine but not opioid transmission in the brain.
D000661:Amphetamine / Q000494:pharmacology*; D000700:Analgesics; D000818:Animals; D001921:Brain / Q000502:physiology*; D004723:Endorphins / Q000502:physiology*; D006220:Haloperidol / Q000494:pharmacology; D008297:Male; D009020:Morphine / Q000494:pharmacology; D009270:Naloxone / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D011930:Reaction Time / Q000187:drug effects
D000700:Analgesics; D004723:Endorphins; D009270:Naloxone; D009020:Morphine; D000661:Amphetamine; D006220:Haloperidol