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Chronic administration of 5-HT1A receptor agonist relieves depression and depression-induced hypoalgesia.

Jiang ZC, Qi WJ, Wang JY, Luo F - ScientificWorldJournal (2014)

Bottom Line: Previous studies have shown that depressed patients as well as animal models of depression exhibit decreased sensitivity to evoked pain stimuli, and serotonin is indicated to be involved in depression-induced hypoalgesia.The depression-like behavior and pain thresholds were measured using open-field test and radiant heat thermal pain test, respectively.In contrast, chronic administration of 8-OH-DPAT reduced locomotor activity and pain thresholds and restored them to normal level.

View Article: PubMed Central - PubMed

Affiliation: Key Laboratory of Mental Health, Institute of Psychology, Chinese Academy of Sciences, Beijing 100101, China ; University of Chinese Academy of Sciences, Beijing 100039, China.

ABSTRACT
Previous studies have shown that depressed patients as well as animal models of depression exhibit decreased sensitivity to evoked pain stimuli, and serotonin is indicated to be involved in depression-induced hypoalgesia. The purpose of this study was to investigate the potential role of 5-HT1A receptor in the depression-induced hypoalgesia. Acute or chronic administration of 5-HT1A receptor agonist, 8-OH-DPAT, was performed in olfactory bulbectomy (OB) and sham-operated rats. The depression-like behavior and pain thresholds were measured using open-field test and radiant heat thermal pain test, respectively. We found that acute administration of 8-OH-DPAT increased locomotor activity and pain thresholds in the sham rats but had no effect on the OB rats. In contrast, chronic administration of 8-OH-DPAT reduced locomotor activity and pain thresholds and restored them to normal level. Increased pain thresholds were also observed in the sham rats after the chronic administration. These results demonstrated that chronic administration of 8-OH-DPAT reversed the depression-induced decrease in pain sensitivity in rats, suggesting that 5-HT1A receptor may play a role in the depression-associated hypoalgesia.

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Related in: MedlinePlus

Behavioral outcome of the OB model for depression and depression-induced hypoalgesia. (a) Body weights. Significant decrease was observed in body weights in the OB group in comparison to the control group over the 14-day postoperation period (n = 33–48). (b) Open-field test. Significant higher level of locomotor activity was found in the OB rats than in the control rats (n = 33–48). (c) Thermal pain threshold test. The paw withdrawal latency to noxious radiant heat stimuli was significantly prolonged in the OB rats (n = 33–48). Data are presented as mean ± SEM.***P < 0.001.
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fig2: Behavioral outcome of the OB model for depression and depression-induced hypoalgesia. (a) Body weights. Significant decrease was observed in body weights in the OB group in comparison to the control group over the 14-day postoperation period (n = 33–48). (b) Open-field test. Significant higher level of locomotor activity was found in the OB rats than in the control rats (n = 33–48). (c) Thermal pain threshold test. The paw withdrawal latency to noxious radiant heat stimuli was significantly prolonged in the OB rats (n = 33–48). Data are presented as mean ± SEM.***P < 0.001.

Mentions: As shown in Figure 2(a), the baseline body weights of animals did not differ between OB and sham groups. During the following two weeks of observation, significant reduction of weight gain was observed in the OB rats as compared to the control rats (two-way ANOVA, group effect: F(1, 1106) = 53.08, P < 0.001; Bonferroni posttests, P < 0.001 every day) (Figure 2(a)). After surgery, the OB rats showed significantly higher level of locomotor behaviors in open-field than that of control rats (two-way ANOVA, 6541 ± 238 versus 2746 ± 147 cm, P < 0.001) (Figure 2(b)). These results indicate that the OB rats have exhibited depressive-like behaviors and the animal model for depression has been successfully established.


Chronic administration of 5-HT1A receptor agonist relieves depression and depression-induced hypoalgesia.

Jiang ZC, Qi WJ, Wang JY, Luo F - ScientificWorldJournal (2014)

Behavioral outcome of the OB model for depression and depression-induced hypoalgesia. (a) Body weights. Significant decrease was observed in body weights in the OB group in comparison to the control group over the 14-day postoperation period (n = 33–48). (b) Open-field test. Significant higher level of locomotor activity was found in the OB rats than in the control rats (n = 33–48). (c) Thermal pain threshold test. The paw withdrawal latency to noxious radiant heat stimuli was significantly prolonged in the OB rats (n = 33–48). Data are presented as mean ± SEM.***P < 0.001.
© Copyright Policy - open-access
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3921963&req=5

fig2: Behavioral outcome of the OB model for depression and depression-induced hypoalgesia. (a) Body weights. Significant decrease was observed in body weights in the OB group in comparison to the control group over the 14-day postoperation period (n = 33–48). (b) Open-field test. Significant higher level of locomotor activity was found in the OB rats than in the control rats (n = 33–48). (c) Thermal pain threshold test. The paw withdrawal latency to noxious radiant heat stimuli was significantly prolonged in the OB rats (n = 33–48). Data are presented as mean ± SEM.***P < 0.001.
Mentions: As shown in Figure 2(a), the baseline body weights of animals did not differ between OB and sham groups. During the following two weeks of observation, significant reduction of weight gain was observed in the OB rats as compared to the control rats (two-way ANOVA, group effect: F(1, 1106) = 53.08, P < 0.001; Bonferroni posttests, P < 0.001 every day) (Figure 2(a)). After surgery, the OB rats showed significantly higher level of locomotor behaviors in open-field than that of control rats (two-way ANOVA, 6541 ± 238 versus 2746 ± 147 cm, P < 0.001) (Figure 2(b)). These results indicate that the OB rats have exhibited depressive-like behaviors and the animal model for depression has been successfully established.

Bottom Line: Previous studies have shown that depressed patients as well as animal models of depression exhibit decreased sensitivity to evoked pain stimuli, and serotonin is indicated to be involved in depression-induced hypoalgesia.The depression-like behavior and pain thresholds were measured using open-field test and radiant heat thermal pain test, respectively.In contrast, chronic administration of 8-OH-DPAT reduced locomotor activity and pain thresholds and restored them to normal level.

View Article: PubMed Central - PubMed

Affiliation: Key Laboratory of Mental Health, Institute of Psychology, Chinese Academy of Sciences, Beijing 100101, China ; University of Chinese Academy of Sciences, Beijing 100039, China.

ABSTRACT
Previous studies have shown that depressed patients as well as animal models of depression exhibit decreased sensitivity to evoked pain stimuli, and serotonin is indicated to be involved in depression-induced hypoalgesia. The purpose of this study was to investigate the potential role of 5-HT1A receptor in the depression-induced hypoalgesia. Acute or chronic administration of 5-HT1A receptor agonist, 8-OH-DPAT, was performed in olfactory bulbectomy (OB) and sham-operated rats. The depression-like behavior and pain thresholds were measured using open-field test and radiant heat thermal pain test, respectively. We found that acute administration of 8-OH-DPAT increased locomotor activity and pain thresholds in the sham rats but had no effect on the OB rats. In contrast, chronic administration of 8-OH-DPAT reduced locomotor activity and pain thresholds and restored them to normal level. Increased pain thresholds were also observed in the sham rats after the chronic administration. These results demonstrated that chronic administration of 8-OH-DPAT reversed the depression-induced decrease in pain sensitivity in rats, suggesting that 5-HT1A receptor may play a role in the depression-associated hypoalgesia.

Show MeSH
Related in: MedlinePlus