Inescapable footshocks induce progressive and long-lasting behavioural changes in male rats.
Long-term behavioural consequences of exposure to a brief (15 min) session of inescapable footshocks (10 x 6 s, 1 mA) were investigated in male rats. The time course of the effects of inescapable footshocks was assessed by studying the behaviour of groups of rats at different post-stress intervals. Footshocked rats (S) did not differ from control (C) rats (exposed to the shock box for 15 min) in their behavioural response to an open field whether tested 1 h or 4 h post-stress. However, one day after shocks, S rats showed less locomotion and rearing, and more immobility and attention as compared to C rats. At 7 days or 14 days post-stress, S rats exhibited decreased locomotion, rearing, sniffing, and grooming, and increased immobility, attention, and defecation relative to C rats. In a second experiment, we investigated whether footshocks affect the behavioural response to a sudden drop in background noise during exposure to a novel environment. At 21 days post-stress, S rats showed a markedly enhanced immobility response to this stimulus as compared to C rats. In order to investigate whether rats could be exposed repeatedly to the open field without affecting the differences in behaviour between the two treatment groups, C and S rats were tested in an open field for the first time at 7 days post-stress, which yielded the typical effects of footshocks. When these rats were exposed to a second open-field test one week later, the behavioural responses of C and S rats were not different.(ABSTRACT TRUNCATED AT 250 WORDS)
Van Dijken
H H
HH
Department of Pharmacology, Medical Faculty, Free University, Amsterdam, The Netherlands.
Van der Heyden
J A
JA
Mos
J
J
Tilders
F J
FJ
D000818:Animals; D001143:Arousal; D001288:Attention; D001522:Behavior, Animal; D004597:Electroshock; D004924:Escape Reaction; D005106:Exploratory Behavior; D006380:Helplessness, Learned; D008297:Male; D011939:Mental Recall; D009043:Motor Activity; D051381:Rats; D011919:Rats, Inbred Strains