Chapter 3. Module 3.2. Chemical events at the synapse Flashcards
Neurotransmitters
Amino acids
Peptides
Acetylcholine
Monoamines
Purines
Gases
The sequences do chemical events at a synapse
The neuron synthesizes chemicals that serve as neurotransmiters
Small ones in axon terminals and the large ones (peptides) in the body
Peptides are transmitted to the axon terminals
At the presynaptic terminal, calcium enters the cell which then allows the release of neurotransmitters into the synaptic cleft
Etc
Amino acids
Acids containing an amine group (NH2)
Peptides
Chains of amino acids
A long chain is called polypeptide
A still longer chain is called a protein
Acetylcholine
(A one-member family) a chemical similar to an amino acid, except at the NH2 group has been replaced by an N(CH3)3 group
Monoamines
Neurotransmitters containing one amine group NH2
Purines
A category of chemicals including adenosine and several of its derivatives
Gases
Nitric oxide and possibly others
Does not have an amino acid
A gas releases by many small local neurons
Poisonous in large quantities and difficult to make in a laboratory
Nitric acid is believed to serve blood flow by dilating vessels and thereby augmenting blood flow to those areas of the brain
Catecholamines
Epinephrine, norepinephrine, and dopamine are three closely related compounds known as catechu lameness because they contain a catechol group and an amino group
Exocytosis
Release of neurotransmitter in Burt’s from the presynaptic neuron into the synaptic cleft and separated this neuron from the postsynaptic neuron
Ionotropic effects
On the postsynaptic neuron: When the neurotransmitter binds to a receptor on the membrane, it almost immediately opens the gate for some type of ion
Metabotropic effects
Initiates a sequence of metabolic reactions that are slower and longer lasting than Ionotropic effects
It facilitates the release of the second messenger G protein which communicates with areas inside the cell
G protein affects larger areas a of the cell and produces longer effects
Neuromodulators
Researchers sometimes describe some Metabotropic neurotransmitters, mainly the peptide neurotransmitters, as neuromodulators, with the implication that they do not directly excite or inhibit the postsynaptic cell but increase or decrease the release of other transmitters or alter the response of postsynaptic cells to various inputs
Reuptake
The presypnatic neuron takes up most of the neurotransmitters molecules intact and reuses them
This process occurs through special membrane protein called transporters
COMT AND MAO
enzymes that convert catecholamine transmitters into inactive chemicals
