Neurotransmitters Flashcards
electrical synapses
two neurons connected by a gap junction, which allows electrical current to flow directly from one cell to the other
what do chemical synapses release?
NT from the presynaptic membrane which bind t receptors of the postsynaptic membrane
chemical synapses specify..
which will happen to a neuron, can regulate depending on what ligands and receptors are present
NT trigger (2) or modulate the postsynaptic cell
EPSPs/IPSPs
quanta
amount of NT located within
where are SNAREs located (2)
vesicle membrane
presynaptic membrane
SNARE proteins I the SV and plasma membrane help to
dock the vesicles and then zip together t oforce the membranes to fuse
– triggers fusion and exocytosis
calcium
botulinum toxin
cleaves SNARES so the vesicle can’t fuse with the membrane which prevents release of acetylcholine and therefore no muscle contraction
botulinum toxin involves (2)
SNAP 25
syntaxin
depending on the NT and the type of receptor it binds to, it can either
excite or inhibit the postsynaptic membrane
excitatory NT (3)
glutamate
aspartame
nitric oxide
inhibitory NT (4)
glycine
GABA
serotonin
dopamine
both excitatory and inhibitory NT (2)
acetylcholine
norepinephrine
resting MP
-65 mV
-65 mV is the potential on the
inside of the neuron
Na+ has a higher concentration — the cell
outside
K+ has a higher concentration — the cell
inside
Ca2+ has a higher concentration — the cell
outside
Mg2+ has a higher concentration — the cell
inside
Cl- has a higher concentration — the cell
outside
EPSP is triggered by (2)
Na+
Cl-
IPSP is triggered by (1)
K+
example of EPSPs
NT opens cation channels for (Na+, Ca2+)
example of IPSP
NT opens Cl- channels
neurons receive numerous inputs from
other neurons synapsing with the dendrites or cell body
where to EPSP and IPSP come together to generate an action potential (or not)
axon hillock
If the graded potential caused by the summation of EPSPs/IPSPs reach a
threshold potential at the axon hillock, this will
open voltage gated Na+ channels and induce an action potential in the neuronal axon
types of neurotransmitters (6)
small molecule transmitters amino acids/derivatives amines proteins/peptides gases endocannabinoids
examples of Small molecule transmitters (2)
Ach
ATP/adenosine
amino acids/derivates (3)
Glutamate (Glu)
Gamma-amminobutyric acid (GABA)
Glycine (Gly)
amines (5)
Serotonin (5-HT) Histamine Dopamine (DA) Norepinephrine (NE) Epinephrine (E)
serotonin is synthesized from
tryptophan
dopamine is synthesized from
tyrosine
examples of Proteins/Peptides (4)
Released by the hypothalamus
Released by the Pituitary
Endorphins
Others
examples of Proteins/Peptides (4)
Released by the hypothalamus
Released by the Pituitary
Endorphins: enkephalins, opiods
Others: Substance P, Bradykinin, Angiotensin II
Released by the hypothalamus- (3)
Thyrotropin-releasing hormone,
Luteinizing hormone releasing hormone,
somatostatin
Released by the Pituitary- (7)
Adrenocorticotropic hormone, prolactin, luteinizing hormone, thyrotropin, growth hormone, vasopressin, oxytocin
Endorphins: (2)
enkephalins, opiods
Others: (3)
Substance P,
Bradykinin,
Angiotensin II
glasses (2)
Nitric oxide (NO) carbon monoxide (CO)
endocannabinoids (2)
Anandamide
arachidonyl glycerol
CB1 receptor
located on presynaptic membrane
potential responses to endocannabinoids (5)
Increase Pleasure Inhibit Pain Inhibit Nausea Decrease Learning/Memory Movement
Types of receptors (3)
Transmitter-gated ion channels, or ionotropic receptors
G-protein-coupled receptors, or metabotropic receptors
Enzyme linked receptors
Transmitter-gated ion channels, or ionotropic receptors (2)
- ion channels (Na+, K+, Cl-, Ca2+)
- depolarize/hyperpolarize cell
G-protein-coupled receptors, or metabotropic receptors (1)
-indirectly linked to ion channels
Enzyme-linked receptors- (1)
tyrosine kinase receptors
inhibiting GABA
increases dopamine
for Ionotropic Receptors- ligand gated, when the neurotransmitter binds to
the receptor it
changes conformation
Opening of ion channels results in an increased
concentration of the ion
inside of the cell
Metabotropic Receptors:
An activated G-protein diffuses in the membrane to act on its
target, which may be an ion channel, enzymes, or gene
transcription.
metabotropic receptors open up ion channels
indirectly
Example of Ionotropic Receptor: GABAA receptor for GABA
Chloride channel
inhibitory, IPSP
selective for chloride
Cl- moves into the cell, which makes it harder for the neuron to fire
GABA
GABA + pentobarbital
GABA + pentobarbital results in even more opening, and therefore more CL- coming in
Example of Inotropic Receptor- NMDA receptor for glutamate
Na+/Ca2+ channel
Na+/Ca2+ channel requires – as a cofactor
glycine
how can glycine act
excitatory in the brain
inhibitory in the spinal cord
channel blocking agonists (3)
ketamine
PCP
memantine
Example: Acetylcholine Ionotropic Receptor
the Nicotinic Receptor
the Nicotinic Receptor is found in (2)
nerves and muscles
antagonist of the Nicotinic Receptor
curare
curare
blocks the channel, paralyzes muscle such as the diaphragm so you can’t breathe
the Nicotinic Receptor mechanism
na+ enters the channel
EPSP
calcium release
muscle contraction
Example: Acetylcholine Metabotropic Receptor
the Acetylcholine Muscarinic Receptor
the Acetylcholine Muscarinic Receptor is
g coupled
the Acetylcholine Muscarinic Receptor is found in
organs
the Acetylcholine Muscarinic Receptor antagonist
atropine
atropine
blocks Ach to increase HR
most common example of the Acetylcholine Muscarinic Receptor
heart
reduces heart rate
— can active both ionotropic and metabotropic receptors
ACh
Nicotinic receptor: Ach
agonist
antagonist
nicotine
curare
Muscarinic receptor: Ach
agonist
antagonist
muscarine
atrophie
N1
N2
skeletal muscle or nerve
postaganglionic neurons
muscarinic receptor:
— actions
found in
parasympathetic
target organs
