Disruptive effect of the mesencephalic reticular formation on tonic immobility in guinea pigs.
Cholinergic stimulation of the mesencephalic reticular formation with carbachol impairs the induction of tonic immobility (TI) by restraining maneuvers and reduces the duration of immobility episodes in guinea pigs. This finding apparently disagrees with the hypothesis that environmental monitoring occurs during TI which permits the animal to evaluate the best time for escape. It is possible that this monitoring involves circuits and neurotransmitters other than the ascending cholinergic system originating in the mesencephalic reticular formation.
Menescal-de-Oliveira
L
L
Departamento de Fisiologia, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Brasil.
Brentegani
M R
MR
Pereira
A F
AF
Hoffmann
A
A
D000818:Animals; D001364:Awareness / Q000502:physiology*; D001522:Behavior, Animal / Q000187:drug effects*; D002217:Carbachol / Q000008:administration & dosage / Q000494:pharmacology*; D003344:Cortical Synchronization / Q000187:drug effects*; D006168:Guinea Pigs; D007103:Immobilization / Q000502:physiology*; D008297:Male; D008845:Microinjections; D012154:Reticular Formation / Q000502:physiology*
D002217:Carbachol