Question

Describe the events of synaptic transmission in proper chronological order from the release of neurotransmitter by synaptic vesicles to the effect of the neurotransmitter on the postsynaptic cell.

Answer 1

When Action Potential Reaches Pre synaptic Membrane---There is Release of Ca2+ from Voltage gated Ca2+ Channels in Pre Synaptic Membrane---This Causes fusion of Synaptic vesicle with pre synaptic Membrane ---which results in the Release of Neurotansmitter(Acetyl CHoline) into Synaptic Cleft.

Neurotransmitters thus released into the synaptic cleft now swim (diffuse) through the synaptic cleft to reach the postsynaptic neuronal Membrane

The neurotransmitter now binds to Neurotransmitter receptors like Acetyl choline receptor found in the membrane membrane of the post synaptic neuron .

Binding of Neurotransmitter (Acetyl Choline) to its receptor in the Post Synaptic Membrane leads to Opening of Voltage gated Na+ channels---this causes Influx of Na+ ions into post synaptic membrane causing Depolarisation in the Post Synaptic Membrane.

Final step is the Degradation or stopping of the Neurotrasmitter-

When neurotransmitter signal is translated into electrical signal(Depolarisation) the postsynaptic receptors need to be cleared so that they can now they can receive new transmitters from new signals.

So Some of neurotransmitters are degraded, some of the neurotransmitters are transported back to the presynaptic terminal which get recycled or gets absorbed by the postsynaptic terminal.