Synaptic transmission

• synaptic transmission refers to the process in which neurons communicate with eachother
• 1 - an action potential reaches the axon terminal of a neuron which causes vesicles to release their contents into the synaptic gap
• 2 - neurotransmitter diffuse across the synaptic gap before binding to specialised receptors on the post-synaptic neuron
• 3 - neurotransmitters can lead to excitation of the post-synaptic neuron

  this occurs when excitatory neurotransmitters like dopamine bind and provides excitatory post-synaptic potentials

  EPSPs increase the positive charge of the post-synaptic neuron, making it more likely to fire
• 3 - neurotransmitters can led to inhibition of the post synaptic neuron

  this occurs when inhibitory neurotransmitters like serotonin bind and provide inhibitory post synaptic potentials

  IPSPs increase the negative charge of the post synaptic neuron making it less likely to fire
• 4 - for the post synaptic neuron to decide whether to fire and action potential, the EPSPs and IPSPs are summed through the summation process

  if the net effect on the post synaptic neuron is inhibitory it will not fire and action potential
• 5 - once neurotransmitters bind to their specialised post synaptic receptors and exert their inhibitory and excitatory effects

  the dissociate and return to the pre synaptic neuron's axon terminal through reuptake transporters

  any remaining in the synaptic gap will be broken down by enzymes
• drugs can increase synaptic transmission by blocking reuptake transporters which means that less neurotransmitters reuptaken
• drugs can decrease synaptic transmission by occupying post synaptic receptors but not exerting any effect

  this therethore blocks any neurotransmitters from binding so they cannot exert their inhibitory or excitatory effects