The context specificity of anxiety responses induced by chronic psychosocial stress in rats: A shift from anxiety to social phobia?

Figures & data

Table I.  Weight gain (g) in controls and stressed rats.

Experiment no.	Stress duration	Stress type	Group housed	Isolated	Stressed	F (p)	N per group
1	5 days	Psychosocial, predictable	27.3 ± 2.76	35.11 ± 5.8	9.66 ± 4.98^*	8.23 (0.002)	9
2	12 days	Psychosocial, predictable	46.3 ± 7.1	45.5 ± 9.4	28.6 ± 6.3	1.70 (0.2)	9
3	5 days	Psychosocial, unpredictable	29.0 ± 2.1	17.8 ± 1.8^*	8.6 ± 3.3^*,^*^*	17.08 (0.0001)	9–12
4	5 days	Psychosocial, unpredictable	30.8 ± 7.3	13.4 ± 2.7^*	2.53 ± 5.9^*,^*^*	6.43 (0.01)	12
5	5 days	Restraint, predictable	–	23.4 ± 6.4	6.42 ± 2.0^*^*	20.87 (0.001)	7

Notes: Values are shown as mean ± SEM. Pairwise comparisons: ^*Significantly different from group housed and ^**Significantly different from isolated.

Table II.  Relative adrenal weights in controls and stressed rats.

Experiment no.	Stress duration	Stress type	Group housed	Isolated	Stressed	F (p)	N per group
1	5 days	Psychosocial, predictable	0.12 ± 0.001	0.13 ± 0.007	0.15 ± 0.006^*	5.62 (0.05)	9
2	12 days	Psychosocial, predictable	0.13 ± 0.004	0.13 ± 0.001	0.16 ± 0.01^*	6.18 (0.04)	9
3	5 days	Psychosocial, unpredictable	0.12 ± 0.003	0.13 ± 0.002	0.14 ± 0.004^*	4.92 (0.02)	9–12
4	5 days	Psychosocial, unpredictable	0.15 ± 0.01	0.16 ± 0.008	0.19 ± 0.006^*,^*^*	5.20 (0.001)	12
5	4 days	Restraint, predictable	–	0.14 ± 0.01	0.15 ± 0.004	0.36 (0.6)	7

Notes: Values (mean ± SEM) are shown as mg adrenal/g body weight. Pairwise comparisons: ^*Significantly different from group housed and ^**Significantly different from isolated.

Figure 1.  The effects of psychosocial stress on elevated plus-maze behavioral variables. No agonistic encounters were performed on the last (testing) day, but subjects remained in sensory contact with dominants throughout. CLe, closed entries; %OPe, percent open arm entries; and OP%t, % time in open arms. Values are group mean+SEM. No significant differences were seen under any of the conditions. Sample size was 9–12 rats per group.

Figure 2.  The effects of psychosocial stress in the social interaction test. No agonistic encounters were performed on the last (testing) day, but subjects remained in sensory contact with dominants throughout. Values are group mean+SEM. *Significantly different from control (p < 0.05 at least); ^#significantly different from both control and isolated rats (p < 0.05 at least). Sample size was nine rats per group.

Figure 3.  The effects of repeated restraint on behavior in the elevated plus-maze. No restraint was performed on the last (testing) day. Values are group mean+SEM. *Significantly different from control (p < 0.05). Sample size was seven rats per group.

Figure 4.  The correlation between body weight gain and the duration of open arm exploration. No correlation was seen in the case of psychosocial stress (R = − 0.064; p>0.7) (upper panel; N = 32). In contrast, the correlation was significant in the case of repeated restraint (R = 0.564; p < 0.04) (lower panel; N = 14).