Pentobarbital-induced hyperactivity in mice: negligible role of opioid mechanisms.
Subhypnotic doses (10 and 20 mg/kg) of pentobarbital significantly elevated locomotor activity measured for 30 min in CD-1 mice. The hyperactivity was also observed in mice recovering from pentobarbital-induced (50 mg/kg) sleep (measurements starting 15 min after recovery of righting reflex). Naloxone in doses up to 4 mg/kg did not affect significantly the pentobarbital-induced hyperactivity in any experiment; a dose of 8 mg/kg only partially attenuated the hyperactivity induced by a dose of 20 mg/kg of pentobarbital, but did not affect significantly either the stimulatory effect of a low subhypnotic dose (10 mg/kg) or the posthypnotic hyperactivity. This suggests a negligible involvement of opioid mechanisms in the hyperactivity induced by pentobarbital.
Vetulani
J
J
Istituto di Psicobiologia e Psicofarmacologia, CNR, Roma, Italy.
Pavone
F
F
Battaglia
M
M
Sansone
M
M
D000818:Animals; D004305:Dose-Response Relationship, Drug; D004347:Drug Interactions; D008297:Male; D051379:Mice; D009043:Motor Activity / Q000187:drug effects*; D009270:Naloxone / Q000494:pharmacology*; D010424:Pentobarbital / Q000494:pharmacology*; D012890:Sleep / Q000187:drug effects
D009270:Naloxone; D010424:Pentobarbital