Pattern of c-Fos expression induced by tail suspension test in the mouse brain. Issue 6 (June 2017)

• Record Type: Journal Article
• Authors: Hiraoka, Kentaro; Motomura, Keisuke; Yanagida, Satoru; Ohashi, Ayako; Ishisaka-Furuno, Nozomi; Kanba, Shigenobu
• Is Part Of: Heliyon. Volume 3:Issue 6(2017)
• Publication Date: 2017-06
• Subjects: Neuroscience; Research -- Periodicals; Medical sciences -- Periodicals; Natural history -- Periodicals; Social sciences -- Periodicals; Earth sciences -- Periodicals; Physical sciences -- Periodicals; 507.2
• DOI: 10.1016/j.heliyon.2017.e00316
• Languages: English
• ISSNs: 2405-8440

Abstract

Abstract: The tail suspension test (TST) has been widely used as a screening assay for antidepressant drugs. However, the neural substrates underlying the stress response and antidepressant-like effect during the TST remain largely unknown despite the prevalence of this test. In the present study, we used immunohistochemistry to examine alterations in c-Fos expression as a measure of neuronal activity in the mouse brain after acute administration of the antidepressant drugs nortriptyline or escitalopram (or saline as a control) with or without a subsequent TST session. We found that without the TST session, nortriptyline administration enhanced the density of c-Fos-immunoreactive cells in regions of the central extended amygdala, paraventricular hypothalamic nucleus, and relevant regions of the brain stem, whereas escitalopram did not change c-Fos expression in any region. Following the TST in the absence of antidepressant drugs, we observed a significant increase in c-Fos-positive cell density in a number of brain regions within the limbic telencephalon, hypothalamus, and brain stem. We detected a statistically significant interaction using an analysis of variance between the main effects of the drug and stress response in four regions: the infralimbic cortex, lateral septal nucleus (intermediate part), ventrolateral preoptic nucleus, and solitary nucleus. Following the TST, escitalopram but not nortriptyline increased c-Fos-positive cell density in the infralimbic cortex and ventrolateral preoptic nucleus, whereas nortriptyline but not escitalopram increased c-Fos expression in the solitary nucleus. Both antidepressants significantly increased c-Fos expression in the lateral septal nucleus (intermediate part). The present results indicate that neuronal activity increases in septo-hypothalamic regions and related structures, especially the lateral septal nucleus, following administration of drugs producing an antidepressant-like effect in mice subjected to the TST.