207 research outputs found
Alterations of synaptic plasticity in Angelman syndrome model mice are rescued by 5-HT7R stimulation
No full textAngelman syndrome (AS) is a severe neurodevelopmental disorder characterized by motor disfunction, seizures, intellectual disability, speech deficits, and autism-like behavior, showing high comorbidity with Autism Spectrum Disorders (ASD). It is known that stimulation of the serotonin receptor 7 (5-HT7R) can rescue some of the behavioral and neuroplasticity dysfunctions in animal models of Fragile X and Rett syndrome, two pathologies associated with ASD. In view of these observations, we hypothesised that alterations of 5-HT7R signalling might also be involved in AS. To test this hypothesis, we stimulated 5-HT7R with the selective agonist LP-211 to investigate its possible beneficial effects on synaptic dysfunctions and altered behavior in the AS mice model. In mutant mice, we observed impairment of the synaptic machinery of protein synthesis, which was reversed by 5-HT7R activation. Moreover, stimulation of 5-HT7R was able to: i) enhance dendritic spine density in hippocampal neurons, which was reduced in AS mice; ii) restore impaired long-term potentiation (LTP) in hippocampal slices of the AS mice; iii) improve cognitive performance of the mutant animals subjected to the fear conditioning paradigm. Altogether, our results, showing beneficial effects of 5-HT7R stimulation in restoring molecular and cognitive deficits associated with AS, suggest that targeting 5-HT7R could be a promising therapeutic approach for the pathology
Calpain-1 and Calpain-2 in the Brain: What Have We Learned from 45 Years of Research?
No full textAlthough the calcium-dependent proteases, calpains, were discovered more than 60 years ago, we still know very little regarding their functions, mostly because very few studies are addressing questions related to specific members of this relatively large family of cysteine proteases. The “classical calpains”, calpain-1 and calpain-2, are ubiquitous and have received more attention because of the special roles they play in the brain. The authors have been studying the properties and functions of these two calpain isoforms in the brain for over 45 years, and this review will focus on what has been learned over this period of time. In particular, we will discuss the numerous studies that have led to the notion that calpain-1 and calpain-2 play opposite functions in the brain on processes ranging from neuronal survival or death, synaptic plasticity, and learning and memory to neurogenesis. Mechanisms underlying these opposite functions are starting to be understood and the findings support the notion that such opposite functions might be a general feature of these two isoforms in any type of cell. This review concludes with a discussion of the potential benefits of selective calpain-2 inhibitors for the treatment of a variety of neurological disorders
Design of automatic curtain controlled by wireless based on single chip 51 microcomputer
No full textRevisiting the calpain hypothesis of learning and memory 40 years later
No full textIn 1984, Gary Lynch and Michel Baudry published in Science a novel biochemical hypothesis for learning and memory, in which they postulated that the calcium-dependent protease, calpain, played a critical role in regulating synaptic properties and the distribution of glutamate receptors, thereby participating in memory formation in hippocampus. Over the following 40 years, much work has been done to refine this hypothesis and to provide convincing arguments supporting what was viewed at the time as a simplistic view of synaptic biochemistry. We have now demonstrated that the two major calpain isoforms in the brain, calpain-1 and calpain-2, execute opposite functions in both synaptic plasticity/learning and memory and in neuroprotection/neurodegeneration. Thus, calpain-1 activation is required for triggering long-term potentiation (LTP) of synaptic transmission and learning of episodic memory, while calpain-2 activation limits the magnitude of LTP and the extent of learning. On the other hand, calpain-1 is neuroprotective while calpain-2 is neurodegenerative, and its prolonged activation following various types of brain insults leads to neurodegeneration. The signaling pathways responsible for these functions have been identified and involve local protein synthesis, cytoskeletal regulation, and regulation of glutamate receptors. Human families with mutations in calpain-1 have been reported to have impairment in motor and cognitive functions. Selective calpain-2 inhibitors have been synthesized and clinical studies to test their potential use to treat disorders associated with acute neuronal damage, such as traumatic brain injury, are being planned. This review will illustrate the long and difficult journey to validate a bold hypothesis
Calpain-Mediated Truncation of Glutamate Ionotropic Receptors: Methods for Studying the Effects of Calpain Activation in Brain Tissue
No full textGuidelines for the use and interpretation of assays for monitoring autophagy in higher eukaryotes
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