PS268 Chapter Notes - Chapter 4: Monoamine Neurotransmitter, Neurotransmitter Receptor, Neurotransmitter
Life Cycle of a Neurotransmitter:
-neurotransmitter molecules are made inside the cell from which they are to be released
-the precursors from which the neurotransmitter is made circulates in the blood supply and
generally in the brain
-a cell that is going to make a particular neurotransmitter needs to bring in the right
precurser in a greater concentration than exists outside the cell
-machinery is built into that cell's membrane for active uptake of the precursor
Synthesis:
-after precursor molecule has been taken up into neuron, it is changed through chemical
reactions
-at each step during synthesis, enzymes help the reactions along
-enzymes themselves are large molecules that recognize the precursor molecule, attach to it
briefly, and hold it in such a way as to make the synthetic chemical reaction occur
-after neurotransmitter molecules have been synthesized, they are stored in small vesicles
near the terminal from which they will be released
-the arrival of the action potential in the presynaptic terminals causes calcium channels to
open and calcium enters the cell and assists the movement of the small vesicles toward the
presynaptic terminal membrane so neurotransmitter can be released into synapse
-several thousand neurotransmitter molecules are released at once and it takes microseconds
for them to diffuse across synapse
Document Summary
Neurotransmitter molecules are made inside the cell from which they are to be released. The precursors from which the neurotransmitter is made circulates in the blood supply and generally in the brain. A cell that is going to make a particular neurotransmitter needs to bring in the right precurser in a greater concentration than exists outside the cell. Machinery is built into that cell"s membrane for active uptake of the precursor. After precursor molecule has been taken up into neuron, it is changed through chemical reactions. At each step during synthesis, enzymes help the reactions along. Enzymes themselves are large molecules that recognize the precursor molecule, attach to it briefly, and hold it in such a way as to make the synthetic chemical reaction occur. After neurotransmitter molecules have been synthesized, they are stored in small vesicles near the terminal from which they will be released.
