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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

CMS failed to induce anhedonia in the animals. The sucrose solution (a) and tap water intake (b) as well as the sucrose solution preference (c) of rat exposed to CMS (black circles) or maintained without stress (white circles) did not change throughout the experiment. Fluid intake of sucrose solution and tap water was expressed as relative to basal consumption in order to avoid baseline differences. Data are expressed as mean ± SEM.
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fig2: CMS failed to induce anhedonia in the animals. The sucrose solution (a) and tap water intake (b) as well as the sucrose solution preference (c) of rat exposed to CMS (black circles) or maintained without stress (white circles) did not change throughout the experiment. Fluid intake of sucrose solution and tap water was expressed as relative to basal consumption in order to avoid baseline differences. Data are expressed as mean ± SEM.

Mentions: Figure 2 shows the sucrose intake (a), the tap water consumption (b), and the sucrose preference (c) of rats exposed to CMS (n = 13, black circles) or maintained without stress (n = 13, white circles). The two-way RM ANOVA indicated that sucrose solution intake was not affected by stress (F1,24 = 2.537, p = 0.124), time of exposure (F3,72 = 2.175, p = 0.098), or the interaction of both factors (F3,72 = 0.975, p = 0.409). In a similar way, tap water consumption did not show significant differences (RM ANOVA, stress: F1,24 = 0.172, p = 0.682; time of exposure: F3,72 = 2.151, p = 0.101; and interaction: F3,72 = 1.248, p = 0.299). Regarding sucrose preference, the statistics indicated differences determined by time (F3,72 = 3.011, p = 0.036) but not by stress (F1,24 = 1.385, p = 0.251) or the interaction of both factors (F3,72 = 0.584, p = 0.627); the main effect of time is due to increase of preference along the experiment (Figure 2(c)).


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)

CMS failed to induce anhedonia in the animals. The sucrose solution (a) and tap water intake (b) as well as the sucrose solution preference (c) of rat exposed to CMS (black circles) or maintained without stress (white circles) did not change throughout the experiment. Fluid intake of sucrose solution and tap water was expressed as relative to basal consumption in order to avoid baseline differences. Data are expressed as mean ± SEM.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

fig2: CMS failed to induce anhedonia in the animals. The sucrose solution (a) and tap water intake (b) as well as the sucrose solution preference (c) of rat exposed to CMS (black circles) or maintained without stress (white circles) did not change throughout the experiment. Fluid intake of sucrose solution and tap water was expressed as relative to basal consumption in order to avoid baseline differences. Data are expressed as mean ± SEM.
Mentions: Figure 2 shows the sucrose intake (a), the tap water consumption (b), and the sucrose preference (c) of rats exposed to CMS (n = 13, black circles) or maintained without stress (n = 13, white circles). The two-way RM ANOVA indicated that sucrose solution intake was not affected by stress (F1,24 = 2.537, p = 0.124), time of exposure (F3,72 = 2.175, p = 0.098), or the interaction of both factors (F3,72 = 0.975, p = 0.409). In a similar way, tap water consumption did not show significant differences (RM ANOVA, stress: F1,24 = 0.172, p = 0.682; time of exposure: F3,72 = 2.151, p = 0.101; and interaction: F3,72 = 1.248, p = 0.299). Regarding sucrose preference, the statistics indicated differences determined by time (F3,72 = 3.011, p = 0.036) but not by stress (F1,24 = 1.385, p = 0.251) or the interaction of both factors (F3,72 = 0.584, p = 0.627); the main effect of time is due to increase of preference along the experiment (Figure 2(c)).

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