Effects of chronic unpredictable mild stress-induced depression on bitter taste receptor expression in mice

With the rapid increase in the pace of life, people are facing increasing pressures of all kinds, and depression has gradually become a serious psychological disorder in human society, strongly affecting normal social and physiological activities. Depression can disrupt an individual's taste perception and potentially result in taste disorders by affecting and altering taste receptors. This disruption can consequently impact their food preferences and overall eating experiences.

In this study, we used the chronic unpredictable mild stress (CUMS) method to establish a depression model in male C57BL/6 J mice and explored the changes in taste receptor expression in the lingual circumvallate papillae (CP) to elucidate the effects of depression on taste. After 6 weeks of CUMS, behavioral performance evaluations, such as forced swim, open field, and elevated plus maze tests, were conducted in depression model mice. A further two-bottle choice test was subsequently performed to determine the effect of depression on bitter taste, and the expression of bitter taste receptors in the lingual CP was detected via immunofluorescence staining.

In this study, we found for the first time that mice with CUMS-induced depression had decreased bitter taste sensitivity through a two-bottle choice test and demonstrated that the expression of T2r5, a receptor related to bitter taste perception, and the expression of secondary taste signaling proteins in the lingual CP were significantly decreased in mice exposed to CUMS, as determined via qRTPCR and immunofluorescence staining.

Our study highlights how CUMS influences the perception of bitterness in the peripheral taste system, potentially elucidating stress-induced changes in eating habits.