Changes in the expression of the vitamin D receptor and LVSCC-A1C in the rat hippocampus submitted to single prolonged stress

Abstract

Vitamin D signaling not only controls calcium (Ca2+) and phosphorus uptake and transport, but also correlates with neurocognitive decline and neurodegenerative diseases. Almost all actions of Vitamin D are mediated by the transcription factor, vitamin D receptor (VDR), which has been widely identified in the central nervous system. Although previous studies have substantially advanced the understanding of the action of VDR in the brain, much remains unknown concerning how VDR relates to stress. Multiple lines of evidence indicate that the downregulation of L-type voltage-sensitive Ca 2+-channels α-1C (LVSCC-A1C) by vitamin D in hippocampal neurons is able to reduce the influx and excitotoxic effects of Ca2+ to neurons. Along these lines, the purpose of the present study was to analyze the relative expression of VDR in the hippocampus of rats exposed to single prolonged stress (SPS) as a putative animal model for human post-traumatic stress disorder (PTSD). Furthermore, changes in the levels of expression of LVSCC-A1C and Ca2+ (neurotransmitter content) were examined during the onset periods of PTSD. The results revealed an increase in the expression of VDR at 1, 3 and 7 days post-stress compared with the control group. The intracellular free Ca2+ levels in the hippocampus increased 1 day after SPS exposure, and then decreased gradually to the normal level at 14 days, consistent with the expression pattern of LVSCC-A1C. These results indicated that VDR may be involved in the pathogenesis of SPS rats, thereby providing an alternative preparation to search for optimal therapeutic strategies for PTSD.