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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

Effect of CMS on male rat's performance in the elevated plus maze. The CMS paradigm did not affect the time spent in the open or closed arms (a), but it increased the number of entries into the closed arms (b), suggesting an anxiogenic effect of CMS. Data are expressed as mean ± SEM. Student's t-test: ∗p < 0.05 versus control group.
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fig4: Effect of CMS on male rat's performance in the elevated plus maze. The CMS paradigm did not affect the time spent in the open or closed arms (a), but it increased the number of entries into the closed arms (b), suggesting an anxiogenic effect of CMS. Data are expressed as mean ± SEM. Student's t-test: ∗p < 0.05 versus control group.

Mentions: The performance of stressed (n = 13, gray bars) or unstressed (n = 13, black bars) male rats on the elevated plus maze test is shown in Figure 4. The time spent in the open or closed arm (Figure 4(a)) did not present significant differences determined by CMS (p = 0.606, p = 0.445, resp.). Similarly, the number of entries into the open arm (Figure 4(b)) did not show such difference (p = 0.667); in contrast, the statistical analysis of the number of entries into the closed arm indicated that the stressed group showed more entrances than the unstressed group (p = 0.010).


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)

Effect of CMS on male rat's performance in the elevated plus maze. The CMS paradigm did not affect the time spent in the open or closed arms (a), but it increased the number of entries into the closed arms (b), suggesting an anxiogenic effect of CMS. Data are expressed as mean ± SEM. Student's t-test: ∗p < 0.05 versus control group.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

fig4: Effect of CMS on male rat's performance in the elevated plus maze. The CMS paradigm did not affect the time spent in the open or closed arms (a), but it increased the number of entries into the closed arms (b), suggesting an anxiogenic effect of CMS. Data are expressed as mean ± SEM. Student's t-test: ∗p < 0.05 versus control group.
Mentions: The performance of stressed (n = 13, gray bars) or unstressed (n = 13, black bars) male rats on the elevated plus maze test is shown in Figure 4. The time spent in the open or closed arm (Figure 4(a)) did not present significant differences determined by CMS (p = 0.606, p = 0.445, resp.). Similarly, the number of entries into the open arm (Figure 4(b)) did not show such difference (p = 0.667); in contrast, the statistical analysis of the number of entries into the closed arm indicated that the stressed group showed more entrances than the unstressed group (p = 0.010).

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