TASK 3 Flashcards
_Neurotransmitter
They are also called synaptic transmitter, chemical transmitter, or simply transmitter. The chemical released from the presynaptic axon terminal that serves as the basis of communication between neurons. So, NEURONS integrate electrical information from many synapses and may then release a chemical or neurotransmitter – an endogenous substance that communicates the result of that information processing to the postsynaptic cell
To be considered a neurotransmitter, a substance should meet the following criteria
_the substance exists in presynaptic axon terminals _the presynaptic cell contains appropriate enzymes for synthesizing the substance _the substance is released in significant quantities when action potentials reach the terminals _specific receptors that recognize the released substance exist on the postsynaptic membrane _experimental application of the substance produces changes in postsynaptic cells _blocking release of the substance prevents presynaptic activity from affecting the postsynaptic cell
receptor
A protein molecule that binds and reacts to molecules of a neurotransmitter or hormone
_metabotropic receptor
– a receptor protein that does not contain an ion channel but may, when activated, use a G protein system to alter functioning of the postsynaptic cell
_G protein
– act as molecular switches inside cells, and are involved in transmitting signals from a variety of stimuli outside a cell to its interior. There are two classes of G proteins. _monomeric small GTPases, _heterotrimeric G protein complexes
_monomeric small GTPases,
It is a kind of G PROTEIN
_heterotrimeric G protein complexes
It is a kind of G PROTEIN, composed by subunits _alpha (α) _beta (β) _gamma (γ)
_ionotropic receptor
– a receptor protein that includes an ion channel that is opened when the receptor is bound by an antagonist LEADS TO _Excitatory postsynaptic potential (EPSPs) _inhibitory postsynaptic potential (IPSPs)
_transporters
– specialized receptors in the presynaptic membrane that recognize neurotransmitter molecules and return to the presynaptic neuron for reuse
_exogenous
– arising from outside the body
_endogenous
– arising from inside the body
_ligand
– substance that binds to receptor molecules
TYPES OF NEUROTRANSMITTERS
_amino acid neurotransmitters _amine neurotransmitters _peptide neurotransmitters _gas neurotransmitters
_amino acid neurotransmitters
a neurotransmitter that is itself an amino acid _GABA _Glycine _Glutamate _Aspartate
_GABA
(gamma-aminobutyric acid) – typically has an inhibitory effect. Most of them (as Valium) are potent tranquillizers _GABA A - ionotropic receptors (gated chloride channels) – when activated they produce fast inhibitory postsynaptic potentials. It is made up by 5 protein subunits surrounding a Cl- ion channel, different combinations of those protein, thus different kinds of GABA A _GABA B – metabotropic receptors, typically producing a slow occurring inhibitory postsynaptic potential _GABA C – receptors that are ionotropic with a chloride channel, but they differ from other GABA receptors in certain details of their subunit structure IT IS A GABA, AMINOACID NEUROTRANSMITTER
_GABA A
- ionotropic receptors (gated chloride channels) – when activated they produce fast inhibitory postsynaptic potentials. It is made up by 5 protein subunits surrounding a Cl- ion channel, different combinations of those protein, thus different kinds of GABA A IT IS A GABA, AMINOACID NEUROTRANSMITTER
_GABA B
– metabotropic receptors, typically producing a slow occurring inhibitory postsynaptic potential IT IS A GABA, AMINOACID NEUROTRANSMITTER
_GABA C
– receptors that are ionotropic with a chloride channel, but they differ from other GABA receptors in certain details of their subunit structure IT IS A GABA, AMINOACID NEUROTRANSMITTER
_glycine
– typically has an inhibitory effect, AMINO ACID NEUROTRANSMITTER
_glutamate
– an amino acid neurotransmitter, the most common excitatory transmitter
_glutamatergic
– referring to cells that use GLUTAMATE as their synaptic transmitter
_excitotoxicity
– the property by which neurons die when overstimulated , as with large amount of GLUTAMATE(produced in phenomenon in which neural injury is involved, such as a stroke or trauma)
_aspartate
– an amino acid neurotransmitter that is excitatory at many synapses
_amine neurotransmitters
a neurotransmitter based on modifications of a single amino acid _quaternary amines _monoamines
_quaternary amines
acetylcholine (ACh)
acetylcholine (ACh)
distributed by neurons called _cholinergic – neurons that distribute acetylcholine in the brain TWO TYPES of acetylcholine _nicotinic (nACh) – most of them are ionotropic , responding rapidly and having an excitatory effect _muscarinic (mACh) – they’re G protein-coupled (metabotropic) receptors, so they have slower responses when activated , and they can be either excitatory or inhibitory. They can be blocked by atropine or scopolamine (drugs)
_nicotinic (nACh)
– most of them are ionotropic , responding rapidly and having an excitatory effect TYPE OF acetylcholine (ACh)
_muscarinic (mACh)
– they’re G protein-coupled (metabotropic) receptors, so they have slower responses when activated , and they can be either excitatory or inhibitory. They can be blocked by atropine or scopolamine (drugs) TYPE OF acetylcholine (ACh)
_cholinergic
– neurons that distribute acetylcholine in the brain
_monoamines
_indoleamines _catecholamine amino neurotransmitters
_indoleamines
modified amino acids derived from the amino acid tryptophan _serotonin (5-HT) _melatonin amino neurotransmitters, MONOAMINES
_catecholamine
derived from the amino acid tyrosine _dopamine (DA) and hippocampus. _norepinephrine (NE) _epinephrine (adrenaline) amino neurotransmitters, MONOAMINES
_serotonin (5-HT)
– a neurotransmitter that is produced in the raphe nuclei (midbrain and brainstem) and is active in structures throughout the cerebral emispheres (only 200 million of the 80-90 billion neurons of the human brain are serotonergic, but they exert widespread influence through the rest of the brain) amino neurotransmitters, monoamines , INDOLAMINES
_serotonergic
- neurons that use serotonin as their synaptic transmitter