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Young-Adult Male Rats' Vulnerability to Chronic Mild Stress Is Reflected by Anxious-Like instead of Depressive-Like Behaviors.

José Jaime HP, Venus BC, Graciela JR, Tania HH, Lucía MM - Neurosci J (2016)

Bottom Line: In a previous study, we found that chronic mild stress (CMS) paradigm did not induce anhedonia in young-adult male rats but it reduced their body weight gain.We found that CMS (1) did not affect sucrose preference, immobility behavior in the forced swimming test, or serum corticosterone; (2) decreased body weight gain; and (3) increased the rat's entries into closed arms of the plus maze and the cumulative burying behavior.These data indicate that young male rats' vulnerability to CMS is reflected as poor body weight gain and anxious-like instead of depressive-like behaviors.

View Article: PubMed Central - PubMed

Affiliation: Laboratorio de Farmacología Conductual, Dirección de Investigaciones en Neurociencias, Instituto Nacional de Psiquiatría Ramón de la Fuente Muñiz, Calzada México-Xochimilco 101, Colonia San Lorenzo Huipulco, Delegación Tlalpan, 14370 Ciudad de México, DF, Mexico.

ABSTRACT
In a previous study, we found that chronic mild stress (CMS) paradigm did not induce anhedonia in young-adult male rats but it reduced their body weight gain. These contrasting results encouraged us to explore other indicators of animal's vulnerability to stress such as anxious-like behaviors, since stress is an etiologic factor also for anxiety. Thus, in this study, we evaluated the vulnerability of these animals to CMS using behavioral tests of depression or anxiety and measuring serum corticosterone. Male Wistar rats were exposed to four weeks of CMS; the animals' body weight and sucrose preference (indicator of anhedonia) were assessed after three weeks, and, after the fourth week, some animals were evaluated in a behavioral battery (elevated plus maze, defensive burying behavior, and forced swimming tests); meanwhile, others were used to measure serum corticosterone. We found that CMS (1) did not affect sucrose preference, immobility behavior in the forced swimming test, or serum corticosterone; (2) decreased body weight gain; and (3) increased the rat's entries into closed arms of the plus maze and the cumulative burying behavior. These data indicate that young male rats' vulnerability to CMS is reflected as poor body weight gain and anxious-like instead of depressive-like behaviors.

No MeSH data available.


Related in: MedlinePlus

The rats' growing rate is reduced by CMS exposure. Compared to unstressed rats (white circles), the relative body weights of rats exposed to CMS (black circles) are lower at the three weeks of stress exposure. Values are expressed as percentage of baseline to avoid effects determined by baseline differences. Data are expressed as mean ± SEM. Tukey test: ∗p < 0.05 and ∗∗∗p < 0.001 versus baseline; ###p < 0.001 versus control group.
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fig3: The rats' growing rate is reduced by CMS exposure. Compared to unstressed rats (white circles), the relative body weights of rats exposed to CMS (black circles) are lower at the three weeks of stress exposure. Values are expressed as percentage of baseline to avoid effects determined by baseline differences. Data are expressed as mean ± SEM. Tukey test: ∗p < 0.05 and ∗∗∗p < 0.001 versus baseline; ###p < 0.001 versus control group.

Mentions: Relative body weight of rats exposed to CMS (n = 13, black circles) or maintained without stress (n = 13, white circles) is shown in Figure 3. Data analysis indicates a significant effect of stress (F1,24 = 37.919, p < 0.001), time of exposure (F3,72 = 6.762, p < 0.001), and the interaction of both factors (F3,72 = 10.213, p < 0.001). Post hoc analysis indicated that the body weight of control rats at week 1, 2, or 3 is higher than their basal value (p < 0.001 in all cases); meanwhile, in the stressed group, only the body weight at week 1 was lower than their basal level (p = 0.041). Tukey test also evidenced the notion that body weight of the stressed group was lower than the weight in the control group at weeks 1, 2, and 3 (p < 0.001 in all cases).


Young-Adult Male Rats' Vulnerability to Chronic Mild Stress Is Reflected by Anxious-Like instead of Depressive-Like Behaviors.

José Jaime HP, Venus BC, Graciela JR, Tania HH, Lucía MM - Neurosci J (2016)

The rats' growing rate is reduced by CMS exposure. Compared to unstressed rats (white circles), the relative body weights of rats exposed to CMS (black circles) are lower at the three weeks of stress exposure. Values are expressed as percentage of baseline to avoid effects determined by baseline differences. Data are expressed as mean ± SEM. Tukey test: ∗p < 0.05 and ∗∗∗p < 0.001 versus baseline; ###p < 0.001 versus control group.
© Copyright Policy - open-access
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC4940564&req=5

fig3: The rats' growing rate is reduced by CMS exposure. Compared to unstressed rats (white circles), the relative body weights of rats exposed to CMS (black circles) are lower at the three weeks of stress exposure. Values are expressed as percentage of baseline to avoid effects determined by baseline differences. Data are expressed as mean ± SEM. Tukey test: ∗p < 0.05 and ∗∗∗p < 0.001 versus baseline; ###p < 0.001 versus control group.
Mentions: Relative body weight of rats exposed to CMS (n = 13, black circles) or maintained without stress (n = 13, white circles) is shown in Figure 3. Data analysis indicates a significant effect of stress (F1,24 = 37.919, p < 0.001), time of exposure (F3,72 = 6.762, p < 0.001), and the interaction of both factors (F3,72 = 10.213, p < 0.001). Post hoc analysis indicated that the body weight of control rats at week 1, 2, or 3 is higher than their basal value (p < 0.001 in all cases); meanwhile, in the stressed group, only the body weight at week 1 was lower than their basal level (p = 0.041). Tukey test also evidenced the notion that body weight of the stressed group was lower than the weight in the control group at weeks 1, 2, and 3 (p < 0.001 in all cases).

Bottom Line: In a previous study, we found that chronic mild stress (CMS) paradigm did not induce anhedonia in young-adult male rats but it reduced their body weight gain.We found that CMS (1) did not affect sucrose preference, immobility behavior in the forced swimming test, or serum corticosterone; (2) decreased body weight gain; and (3) increased the rat's entries into closed arms of the plus maze and the cumulative burying behavior.These data indicate that young male rats' vulnerability to CMS is reflected as poor body weight gain and anxious-like instead of depressive-like behaviors.

View Article: PubMed Central - PubMed

Affiliation: Laboratorio de Farmacología Conductual, Dirección de Investigaciones en Neurociencias, Instituto Nacional de Psiquiatría Ramón de la Fuente Muñiz, Calzada México-Xochimilco 101, Colonia San Lorenzo Huipulco, Delegación Tlalpan, 14370 Ciudad de México, DF, Mexico.

ABSTRACT
In a previous study, we found that chronic mild stress (CMS) paradigm did not induce anhedonia in young-adult male rats but it reduced their body weight gain. These contrasting results encouraged us to explore other indicators of animal's vulnerability to stress such as anxious-like behaviors, since stress is an etiologic factor also for anxiety. Thus, in this study, we evaluated the vulnerability of these animals to CMS using behavioral tests of depression or anxiety and measuring serum corticosterone. Male Wistar rats were exposed to four weeks of CMS; the animals' body weight and sucrose preference (indicator of anhedonia) were assessed after three weeks, and, after the fourth week, some animals were evaluated in a behavioral battery (elevated plus maze, defensive burying behavior, and forced swimming tests); meanwhile, others were used to measure serum corticosterone. We found that CMS (1) did not affect sucrose preference, immobility behavior in the forced swimming test, or serum corticosterone; (2) decreased body weight gain; and (3) increased the rat's entries into closed arms of the plus maze and the cumulative burying behavior. These data indicate that young male rats' vulnerability to CMS is reflected as poor body weight gain and anxious-like instead of depressive-like behaviors.

No MeSH data available.


Related in: MedlinePlus