Effects of naloxone, metenkephalin, and morphine on phencyclidine-induced behavior in the rat.
The effects of naloxone, metenkephalin, and morphine were tested on phencyclidine(PCP)-induced stereotyped behaviors, ataxia, and hyperactivity in the rat. Naloxone (8 mg/kg) significantly decreased stereotypy, ataxia, and hyperactivity across all PCP doses tested (2.0, 4.0, and 6.0 mg/kg). Metenkephalin (40 micrograms/kg) and morphine (5 and 10 mg/kg) increased ataxia at the 4.0 and 6.0 mg/kg PCP doses. Stereotypy was altered by the opiates in a dose-dependent manner; enhanced by metenkephalin (40 micrograms/kg) at 2.0 mg/kg and inhibited by metenkephalin (40 micrograms/kg) and morphine (10 mg/kg) at 4.0 and 6.0 mg/kg PCP. Locomotor activity was increased by morphine (5 mg/kg) at 2 mg/kg PCP. These results suggest an involvement of central opiate receptor mechanisms in the mediation of PCP-induced behaviors in the rat.
D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects*; D004305:Dose-Response Relationship, Drug; D004744:Enkephalin, Methionine / Q000494:pharmacology*; D006801:Humans; D008297:Male; D009020:Morphine / Q000494:pharmacology*; D009043:Motor Activity / Q000187:drug effects; D009048:Motor Skills / Q000187:drug effects; D009270:Naloxone / Q000494:pharmacology*; D010622:Phencyclidine / Q000494:pharmacology*; D051381:Rats; D011916:Rats, Inbred F344; D013239:Stereotyped Behavior / Q000187:drug effects
D009270:Naloxone; D004744:Enkephalin, Methionine; D009020:Morphine; D010622:Phencyclidine