Behavioral characterization of morphine effects on motor activity in mice.
A biphasic effect of morphine on locomotion has been extensively described. Nevertheless, the effects of this opioid on other behavioral parameters have been overlooked. The aim of the present study was to verify the effects of different doses of morphine on motor behaviors observed in an open-field. Adult female mice were injected with saline or morphine (10, 15 and 20 mg/kg, i.p.) and observed in an open-field for quantification of locomotor and rearing frequencies as well as duration of immobility and grooming. The lowest dose of morphine decreased locomotion (and increased immobility duration) while the highest dose increased it. All doses tested decreased rearing and grooming. Thus, the effects of morphine on locomotion do not parallel to its effects on rearing and grooming. Our results indicate that locomotion not always reflects the effect of drugs on motor activity, which can be better investigated when other behavioral parameters are concomitantly taken into account.
Patti
Camilla L
CL
Department of Pharmacology, Universidade Federal de São Paulo, Edifício José Leal Prado, Rua Botucatu, 862, CEP 04023-062 São Paulo, SP, Brazil.
Frussa-Filho
Roberto
R
Silva
Regina H
RH
Carvalho
Rita C
RC
Kameda
Sonia R
SR
Takatsu-Coleman
André L
AL
Cunha
Jaime L S
JL
Abílio
Vanessa C
VC
D000701:Analgesics, Opioid / Q000494:pharmacology; D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects*; D004305:Dose-Response Relationship, Drug; D005260:Female; D006120:Grooming / Q000187:drug effects; D051379:Mice; D009020:Morphine / Q000494:pharmacology*; D009043:Motor Activity / Q000187:drug effects*
D000701:Analgesics, Opioid; D009020:Morphine