Introns That Make Change; MicroRNAs and Synaptic Plasticity

Synapses are functional units, transfer and store information within nervous system. Synaptic plasticity is characterized as modification of synapses in response to stimulation they receive. Functional plasticity refers to electrophysiological or chemical signaling, while structural plasticity denotes fundamental changes of number or structure of neurons. This process constitutes underlying mechanism in memory, learning and also drug addiction. Furthermore, synaptic plasticity plays an essential role in post-stroke rehabilitation. As well as many other mechanisms, synaptic plasticity originate from neuronal-plasticity genes. Small, noncoding miRNAs emerged as principal regulators, exerttheir influence beyond transcription. Although rarely they can promote translation, miRNAs predominantly function as post-transcriptional inhibitory molecules. These molecules base-pair with corresponding sequences in 3ʹ-UTR within mRNA and either suppress mRNA translation or promote deadenylation and degradation of them. Plenty of these bio-molecules have been detected in mammalian brains, participatingin various functions. miRNA and precursor-miRNA has been identified in axons and dendrites, far away from the soma. They control the expression of NMDA receptors, AMPA receptors and signaling molecules. In addition, miRNAs can be locally regulated by synaptic activity.For instance, recent evidence suggests that NMDA receptors modulate processing of dendritic precursormiRNA. Besides functional plasticity, contribution of miRNAs like miRNA-188 and miRNA-132 to dendritic spine number and morphology has been demonstrated.These findings are in accord with considerable literature signifies the role of miRNAs in long-term potentiation (LTP) and long-term depression (LTD). Recently, miRNAs have drawn great deal of attraction. Despite considerable number of identified miRNAs, just a fewof them have been investigated functionally. As a gene is targeted by multiple miRNAs and synaptic activity alters several miRNAs simultaneously, new laborious technologies are required to be developed. Conclusion: Since these bio-regulators possess undeniable role inneuroplasticity, they can be reliable pharmaceutical targets for treatment of addiction, stroke and otherneurodegenerative diseases.