Metyrapone decreases locomotion acutely.
Metyrapone is a glucocorticoid synthesis inhibitor known to induce a stress-like biological syndrome, but also to limit stress-related behaviours. Since stress is usually associated to an increased locomotion, the aim of the study was to determine whether metyrapone will increase, decrease or respect locomotion. Forty rats were placed in infrared actimeters to study spontaneous locomotion before and after injecting 150 mg kg(-1) of either metyrapone (n=20) or saline (n=20). Two hours after injection, half of each treatment group animals were tested in an open field to study test-evoked locomotion. Stress-induced analgesia was quantified using plantar test just before blood sampling. Immediately after injection, metyrapone decreased drastically horizontal and vertical locomotion. During the open field test, metyrapone-treated rats remained less active with slower movement execution than saline-treated rats. Metyrapone did not modify plantar test performances but blunted stress-induced corticosterone and ACTH increases. Mechanisms by which metyrapone induced these effects on locomotion are further discussed.
Pôle Neurophysiologie du stress, Département des Facteurs humains, CRSSA, 24 avenue du maquis du Grésivaudan, La Tronche Cedex, France. fredericcanini@crssa.net
Frédéric
F
Canini
Sabrina
S
Brahimi
Jean-Baptiste
JB
Drouet
Virginie
V
Michel
Antonia
A
Alonso
Alain
A
Buguet
Raymond
R
Cespuglio
D000818:Animals; D000963:Antimetabolites / Q000008:administration & dosage; D004305:Dose-Response Relationship, Drug; D005684:Gait / Q000187:drug effects* / Q000502:physiology*; D008124:Locomotion / Q000187:drug effects* / Q000502:physiology*; D008297:Male; D008797:Metyrapone / Q000008:administration & dosage*; D009043:Motor Activity / Q000187:drug effects* / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley
D000963:Antimetabolites; D008797:Metyrapone