Neuroscience

To ensure one way communication of impulses. 

To release neurotransmitters and facilitate transmission of signals.

Synaptic vesicles are small vesicles clustered at presynaptic terminals. Their role is to store and release neurotransmitters, which is triggered by exocytosis. This ensures signals to be transmitted in one direction only.

Synaptic vesicles  Chemical synapses provide the predominant form of fast functional information transfer between neurons in the brain. Synaptic transmission is initiated in a presynaptic neuron when neurotransmitter-containing vesicles release their contents into the synaptic cleft, which physically separates the presynaptic and postsynaptic neurons. The released neurotransmitter molecules then bind to their cognate receptors on the postsynaptic neuron, eliciting an array of chemical and electrical changes. Early physiological studies made profound contributions to our understanding of the discrete (quantal) nature of neurotransmitter release and its calcium-dependence. Over the past two decades, our knowledge of synapse operation has been advanced by molecular biological, genetic and biochemical The presynaptic terminal, located along the axon of most neurons, is a compartment where neurotransmitter-containing vesicles cluster near a highly specialized region of the plasma membrane called the ‘active zone’. From there, vesicles release their contents during synaptic transmission. There are exceptions to this general architecture — for example, presynaptic specializations can occur in dendrites rather than in axons and there are synapses specialized for continuous release that do not have conventional active zones, but have ‘ribbons’. Before neurotransmitter release can occur from a given release site, synaptic vesicles must be sorted, translocated to the active zone, dock and be primed for fusion. Synaptic vesicle recycling is an integral feature of presynaptic function, therefore, we have chosen the synaptic vesicle cycle as the central theme of this Primer.  trafficking and recycling. In fact, when axons are severed from their soma, the terminals are capable of remaining functional for quite some time. In addition to synaptic vesicles, the presynaptic terminal is enriched with components required for both exocytosis and endocytosis: these include specialized neurotransmitter transporters to repackage empty vesicles; endosome organelles that might mediate some aspects of vesicle recycling; elements of smooth endoplasmic reticulum that may regulate intracellular Ca2+; mitochondria to meet the energy demands placed on the vesicle cycle; and a matrix of cytoskeletal elements and scaffolding proteins thought to facilitate synaptic vesicle sorting. A large number of cytoplasmic and plasma membrane proteins that appear to play regulatory roles are also found in synapses.The reason is , synaptic vesicles contain neurotransmitters. These neurotransmitters are then released into synaptic clefts and then mediate their action on postsynaptic neurons.  Well to understand the concept of how neurotransmitters work, we first need to understand the role of voltage-gated ca channels located in the presynaptic neuron and the mechanisms on how they are exocytosed into the cleft. I will be glad to explain these steps in further detail with the help of some videos and talk about some diseases underlying the concepts of neurotransmitters. I hope this will help you ! Thanku !