ABSTRACT
Several cellular responses depend on translational regulation and in most cases, this involves the formation of cytoplasmic granules that contain repressed mRNAs. In neurons, numerous mRNAs travel along dendrites to be locally regulated upon synapse activity and we have recently shown that the exoribonuclease XRN1 forms dynamic aggregates at the post synapse that respond to specific stimuli.(1) These foci were termed SX-bodies and are distinct from stress granules (SGs), processing bodies (PBs) and other RNA granules previously described. Together with Smaug1-foci and FMRP-granules, the SX-bodies contribute to dynamically shape the transcriptome available for translation at the post-synapse.
ABSTRACT
Currently, several studies addresses the novel link between sleep and dopaminergic neurotransmission, focusing most closely on the mechanisms by which Parkinson's disease (PD) and sleep may be intertwined. Therefore, variations in the activity of afferents during the sleep cycles, either at the level of DA cell bodies in the ventral tegmental area (VTA) and/or substantia nigra pars compacta (SNpc) or at the level of dopamine (DA) terminals in limbic areas may impact functions such as memory. Accordingly, we performed striatal and hippocampal neurochemical quantifications of DA, serotonin (5-HT) and metabolites of rats intraperitoneally treated with haloperidol (1.5 mg/kg) or piribedil (8 mg/kg) and submitted to REM sleep deprivation (REMSD) and sleep rebound (REB). Also, we evaluated the effects of REMSD on motor and cognitive parameters and SNpc c-Fos neuronal immunoreactivity. The results indicated that DA release was strongly enhanced by piribedil in the REMSD group. In opposite, haloperidol prevented that alteration. A c-Fos activation characteristic of REMSD was affected in a synergic manner by piribedil, indicating a strong positive correlation between striatal DA levels and nigral c-Fos activation. Hence, we suggest that memory process is severely impacted by both D2 blockade and REMSD and was even more by its combination. Conversely, the activation of D2 receptor counteracted such memory impairment. Therefore, the present evidence reinforce that the D2 receptor is a key player in the SNpc neuronal activation mediated by REMSD, as a consequence these changes may have direct impact for cognitive and sleep abnormalities found in patients with PD. This article is part of the Special Issue entitled 'The Synaptic Basis of Neurodegenerative Disorders'.