Linping Wang , Weiyao Wang , Yingshun Li , Hua Jin , Bin Xiao , Qinghua Jin
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引用次数: 0
Abstract
There is increasing evidence that chronic stress (CS), which occurs when the body is exposed to prolonged stressors, significantly impairs learning and memory. Dopamine (DA) plays a critical role in learning and memory in the hippocampus through the activation of D1-like receptors (D1R). However, the specific roles of DA and D1R in the hippocampal dentate gyrus (DG), particularly in CS-induced changes in spatial learning and memory, are not well understood. In this study, we established a CS rat model through the random application of various stressors. We assessed spatial learning and memory using the Morris water maze (MWM) and measured DA concentration and the amplitude of field excitatory postsynaptic potentials (fEPSP) in the DG during the MWM test in freely moving rats. We also examined the involvement of D1R in spatial learning and memory by microinjecting its antagonist (SCH23390) into the DG, and then analyzed the expressions of phosphorylated (p-) Ca2+/calmodulin-dependent protein kinase II (CaMKII), protein kinase A (PKA), and cAMP-response element binding protein (CREB) in the DG using Western blot. During the MWM test, compared with the control group, the escape latency was increased, and the percentage of distance in target quadrant and the number of platform crossings were decreased, in addition, the increase of fEPSP amplitude in the DG was significantly attenuated in CS group. In the control group, the DA concentration in the DG was significantly increased during the MWM test, and this response was enhanced in the CS group. Microinjection of SCH23390 into the DG significantly improved the spatial learning and memory impairments in CS rats, and reversed the inhibitory effect of CS on increase of fEPSP amplitude in the DG during the MWM test. Furthermore, SCH23390 partially reversed the inhibitory effects of CS on the expressions of p-CaMKII, p-PKA, and p-CREB in the DG. Our findings suggest that overactivation of the DA-D1R system in the hippocampal DG impairs spatial learning and memory and related synaptic plasticity in CS rats via downregulation of PKA-CREB signaling pathway.
期刊介绍:
Neurobiology of Stress is a multidisciplinary journal for the publication of original research and review articles on basic, translational and clinical research into stress and related disorders. It will focus on the impact of stress on the brain from cellular to behavioral functions and stress-related neuropsychiatric disorders (such as depression, trauma and anxiety). The translation of basic research findings into real-world applications will be a key aim of the journal.
Basic, translational and clinical research on the following topics as they relate to stress will be covered:
Molecular substrates and cell signaling,
Genetics and epigenetics,
Stress circuitry,
Structural and physiological plasticity,
Developmental Aspects,
Laboratory models of stress,
Neuroinflammation and pathology,
Memory and Cognition,
Motivational Processes,
Fear and Anxiety,
Stress-related neuropsychiatric disorders (including depression, PTSD, substance abuse),
Neuropsychopharmacology.