Behavioural brain research
-
Sleep deprivation (SD) has been shown to induce oxidative stress which causes cognitive impairment. Melatonin, an endogenous potent antioxidant, protects neurons from oxidative stress in many disease models. The present study investigated the effect of melatonin against SD-induced cognitive impairment and attempted to define the possible mechanisms involved. ⋯ The results of immunoreactivity showed that SD decreased gray values of BDNF and CaMKII in CC and hippocamal CA1, CA3 and dentate gyrus regions, whereas melatonin improved the gray values. In conclusion, our results suggest that melatonin prevents cognitive impairment induced by SD. The possible mechanism may be attributed to its ability to reduce oxidative stress and increase the levels of CaMKII and BDNF in CC and hippocampus.
-
In contextual fear conditioning animals have to integrate various elemental stimuli into a coherent representation of the condition and then associate context representation with punishment. Although several studies indicated the modulating role of endocannabinoid system (ECS) on the associative learning, ECS effect on contextual fear conditioning requires further investigations. The present study assessed the effects of the increased endocannabinoid anandamide (AEA) tone on acquisition, retrieval and extinction of the contextual fear conditioning. ⋯ ECS activation influenced the extinction process and contrasted the stress effects on fear memory. Furthermore, CB1 receptor antagonist blocked and TRPV1 channel antagonist promoted short- and long-term extinction. The present study indicates that ECS controls the extinction of aversive memories in the contextual fear conditioning.
-
In order to identify the differences for the onset and progression of functionally distinct cholinergic innervation disorders, we investigated the effect of bilateral nucleus basalis (NB) and pedunculopontine tegmental nucleus (PPT) lesions on sleep/wake states and electroencephalographic (EEG) microstructure in rats, chronically implanted for sleep recording. Bilateral NB lesion transiently altered Wake/NREM duration within the sensorimotor cortex, and Wake/REM duration within the motor cortex, while there was no change in the sleep/wake states distributions following the bilateral PPT lesion. Bilateral PPT lesion sustainably increased the Wake/REM and REM/Wake transitions followed by inconsistent dysregulation of the NREM/REM and REM/NREM transitions in sensorimotor cortex, but oppositely by their increment throughout four weeks in motor cortex. ⋯ In contrast, the bilateral NB lesion only augmented REM theta in sensorimotor cortex during three weeks. We have shown that the NB and PPT lesions induced differing, structure-related EEG microstructure and transition structure disturbances particularly expressed in motor cortex during NREM and REM sleep. We evidenced for the first time the different topographical expression of the functionally distinct cholinergic neuronal innervation impairment in rat.
-
Previously our study has demonstrated that long-term treadmill exercise improved cognitive deficit in APP/PS1 transgenic mice of Alzheimer's disease (AD) paralleled by enhanced long-term potentiation (LTP). The present study was undertaken to further investigate whether the treadmill running could inhibit the progression of Alzheimer's disease (AD)-like neuropathology in hippocampus of the APP/PS1 mouse models of AD, and to define a potential molecular mechanism underlying the exercise-induced reduction in AD-like neuropathology. Five months of treadmill exercise resulted in a robust reduction in β-amyloid (Aβ) deposition and tau phosphorylation in the hippocampus of APP/PS1 mice. ⋯ We also observed GSK3, rather than CDK5, was inhibited by treadmill exercise. These results indicate that treadmill exercise is sufficient to inhibit the progression of AD-like neuropathology in the hippocampus of APP/PS1 transgenic mouse model, and may mediate APP processing in favor of reduced Aβ deposition. In addition, we demonstrate that treadmill exercise attenuates AD-like neuropathology in AD transgenic mice via a GSK3 dependent signaling pathway.
-
Bile duct ligation (BDL) is shown to induce cholestasis-related liver function impairments as well as consequent cognitive dysfunctions (i.e. impaired learning and memory formation). Glutamatergic neurotransmission plays an important role in hippocampal modulation of learning and memory function. The present study aimed to investigate the possible involvement of dorsal hippocampal (CA1) glutamatergic systems upon cholestasis-induced amnesia. ⋯ Our findings suggest the potential involvement of CA1 glutamatergic system(s) in cholestasis-induced memory deficits.