Prior electrical stimulation of dorsal periaqueductal grey matter or deep layers of the superior colliculus sensitizes rats to anxiety-like behaviors in the elevated T-maze test.
Electrical stimulation of the dorsal periaqueductal grey matter (DPAG) and deep layers of the superior colliculus (DLSC) of the rat elicits anxiety-like reactions such as freezing and flight. The temporal course of the effects of the aversive electrical stimulation of the DPAG (5, 15 and 30 min afterward) and DLSC (5, 10 and 15 min afterward) on the defensive response of rats exposed to elevated T-maze were determined. The elevated T-maze generates two defensive behaviors, inhibitory avoidance and one-way escape, which have been related, respectively, to generalized anxiety and panic disorders. Prior electrical stimulation of the DPAG (15 min) and DLSC (5 min) enhanced inhibitory avoidance when compared to no-operated and sham animals, although not affecting escape. Therefore, stimulation of the DPAG and DLSC causes a heightened responsivity to anxiogenic stimulus, but not to panicogenic stimulus, inherent to elevated T-maze. These findings support the participation of the DPAG and DLSC in the elaboration of adaptive responses to stressful situations. Besides, the data supports the view that prior electrical stimulation of DPAG and DLSC is selective in sensitizing rats to anxiety-like behaviors, but not to panic-like behaviors in the elevated T-maze test.
Laboratory of Comparative Psychology, School of Psychology, University Estácio de Sá, 20260-060 Rio de Janeiro, RJ, Brazil.
Leandro Pinto
LP
de Almeida
Patrício Lemos
PL
Ramos
José Eduardo
JE
Pandossio
Jesus
J
Landeira-Fernandez
Hélio
H
Zangrossi
Regina Lúcia
RL
Nogueira
D000818:Animals; D001007:Anxiety / Q000209:etiology* / Q000503:physiopathology; D001362:Avoidance Learning / Q000528:radiation effects; D001522:Behavior, Animal / Q000528:radiation effects; D004558:Electric Stimulation; D004924:Escape Reaction / Q000528:radiation effects; D007266:Inhibition, Psychological; D008297:Male; D018782:Maze Learning / Q000528:radiation effects*; D010487:Periaqueductal Gray / Q000528:radiation effects*; D051381:Rats; D017208:Rats, Wistar; D011930:Reaction Time / Q000528:radiation effects; D013477:Superior Colliculi / Q000528:radiation effects*; D013997:Time Factors