The influence of p-chlorophenylalanine on different morphine effects.
p-Chlorophenylalanine (p-CPA) reduces brain 5-hydroxytryptamine (5-HT) without altering the dopamine and norepinephrine content. Morphine does not influence the 5-HT level, but partly reverses the depletion of 5-HT by p-CPA. Morphine analgesia and toxicity are not affected by p-CPA treatment. p-CPA also has no effect on acute morphine hypothermia, but after chronic treatment of 5-HT-deficient mice the dose--response curve is no longer parallel, which suggests that another mode of morphine hypothermia occurs. p-CPA diminishes morphine-induced running after acute as well as after chronic morphine administration. p-CPA treatment reduces the sensitivity to the naloxone-precipitated withdrawal reaction, but does not affect the development of physical dependence.
D000698:Analgesia; D000818:Animals; D001831:Body Temperature / Q000187:drug effects; D001923:Brain Chemistry / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D010134:Fenclonine / Q000494:pharmacology*; D006801:Humans; D008297:Male; D051379:Mice; D009020:Morphine / Q000494:pharmacology*; D009021:Morphine Dependence / Q000209:etiology; D009043:Motor Activity / Q000187:drug effects; D009270:Naloxone / Q000494:pharmacology; D012701:Serotonin / Q000032:analysis / Q000502:physiology
D012701:Serotonin; D009270:Naloxone; D009020:Morphine; D010134:Fenclonine