Metabotropic receptors on the other hand activate second messenger cascade systems that result in the opening of ion channel located some place else on the same postsynaptic membrane.
Once bounded with Ca2 , the vesicles dock and fuse with the presynaptic membrane, and release neurotransmitters into the synaptic cleft by a process known as exocytosis.
The neurotransmitters then diffuse across the synaptic cleft and bind to postsynaptic receptors embedded on the postsynaptic membrane of another neuron.
The undershoot phase occurs because unlike voltage-gated sodium channels, voltage-gated potassium channels inactivate much more slowly.
Nevertheless, as more voltage-gated K channels become inactivated, the membrane potential recovers to its normal resting steady state..
Some neurons such as photoreceptor cells, for example, do not have myelinated axons that conduct action potentials.
Other unipolar neurons found in invertebrates do not even have distinguishing processes such as dendrites.
When there is a change in voltage in the terminal bouton, voltage-gated calcium channels embedded in the membranes of these boutons become activated.
These allow Ca2 ions to diffuse through these channels and bind with synaptic vesicles within the terminal boutons.
When ionotropic receptors are activated, certain ion species such as Na to enter the postsynaptic neuron, which depolarizes the postsynaptic membrane.
If more of the same type of postsynaptic receptors are activated, then more Na will enter the postsynaptic membrane and depolarize cell.
Neurons are cells that are specialized to receive, propagate, and transmit electrochemical impulses.