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Query: UMLS:C0848237 (acute stress)
 4,619 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Acute stressful events enhance plasma corticosterone release and profoundly affect synaptic functions, which are involved in the development of stress-related cognitive and mental disorders. However, how exposure to stressful context immediately after stress further modulates the physiological responses is not fully understood. Here, we found that acute stress inhibited paired-pulse facilitation in hippocampal slices of Wistar rats which were subjected to contextual fear conditioning. But such inhibition was reversed by subsequent prolonged exposure to foot-shock context or returning to home cage for 1 h. Interestingly, foot-shock stress-facilitated LTD induced by low frequency stimulation (LFS, 900 pulses at 1 Hz) was maintained by subsequent exposure to foot-shock context but was reversed by returning to home cage environment. Moreover, plasma corticosterone level was still kept higher in rats exposed to foot-shock context but not to home cage. Findings suggest that remaining in stressful environment immediately after stress maintains acute stress-facilitated LTD and higher level of neuroendocrine response. Our results also contribute to further understanding the critical role of timely intervention in mediating stress-related aversive changes in human.
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PMID:Effects of prolonged exposure to context following contextual fear conditioning on synaptic properties in rat hippocampal slices. 1851 42

The amygdala mediates many forms of emotional learning, during which the central nucleus of amygdala (CeA) functions as a major output of the amygdala by converging inputs from the basolateral nucleus (BLA) and other amygdalar subregions. However, the contribution of BLA-CeA synaptic transmission and plasticity of this transmission after exposure to emotional stimuli remains to be completely understood. Using paired recording, we simultaneously recorded BLA and CeA neurons, and observed that BLA-CeA transmission was glutamatergic. In this transmission, high-frequency stimulation induced NMDA receptor (NMDAR)-dependent LTP, low-frequency stimulation induced NMDAR-dependent LTD, whereas modest-frequency stimulation induced cannabinoid receptor1 (CB1)-dependent LTD. After acute stress, CB1-dependent LTD of this transmission was selectively abolished. This effect of stress was mimicked by intra-CeA administration of CB1-selective agonists and prevented by CB1-selective antagonists. Furthermore, intra-CeA administration of CB1 antagonists prevented stress-induced reduction of explorative behaviors. These results indicate that CB1 signaling-mediated plasticity in local circuits of the amygdala plays a critical role in emotional responses.
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PMID:Long-Term Plasticity in Amygdala Circuits: Implication of CB1-Dependent LTD in Stress. 2859 36