Neurotransmitters Flashcards
What amino acid and neurotransmitter is particularly important for learning and memory?
glutamate
Adrenocorticotropic hormone, prolactin, luteinizing hormone, thyrotropin, growth hormone, vasopressin, and oxytocin are all released by the _____.
pituitary gland
How are action potentials mediated?
via voltage-gated sodium (Na) channels
____ is the amino acid precursor to dopamine, norepinephrine, and epinephrine.
Tyrosine
When acetylcholine binds to the muscarinic receptor in an organ, its G-protein binds to and opens what ion channel? What happens?
K+ channel; K+ rushes out of the cell, hyperpolarizing the cell and making it less excitable (more negative than it was)
What are the steps that must happen in order to release neurotransmitters?
- stimulus must occur
- IPSP/EPSP must reach threshold potential
- voltage-gated Na+ channels open
- run down axon as an action potential
- action potential triggers voltage-gated Ca+ channels to open and allow Ca+ influx
- calcium triggers vesicles to fuse and release contents
Do ionotropic or metabotropic receptors have more immediate effects?
ionotropic (but scope is more narrow)
The influx of negative charge into the cell (e.g. Cl-) causes an _____ response.
IPSP (inhibitory)
Why are patients with Parkinson’s given supplements of L-DOPA?
because L-DOPA is a precursor to dopamine and dopamine is involved in movement
Which enzyme facilitates the synthesis of acetylcholine?
choline acetyltransferase
____ utilize activated G-proteins to diffuse into the membrane and act on ion channels*, enzymes, or gene transcription.
Metabotropic receptors
*most important
What type of synapse contains two neurons connected by a gap junction?
electrical synapse
The voltage gated Na channels open and ____ rushes into the cell, depolarizing it and causing an action potential.
Na
Where does the action potential run?
down the axon of the presynaptic neuron
Where are the voltage-gated Na+ channels located?
all along the axon (spreads down the length of it)
What are the ion concentrations of Mg2+ outside and inside the cell?
outside = 1.2 inside = 58
What are the ion concentrations of K+ outside and inside the cell?
outside = 4 inside = 140
_____ is the amount of neurotransmitter packaged into a synaptic vesicle.
Quanta
Glutamate, aspartate, and nitric oxide are _____ neurotransmitters.
excitatory
Where is the final neuronal signal sent out from (from the summation of multiple different EPSP and IPSP signals)?
axon hillock
Is atropine an agonist or antagonist to the muscarinic receptor?
antagonist (blocks channel)
Can beta-1 receptors bind both epinephrine and norepinephrine?
YES - epinephrine affinity is greater
What ion does the acetylcholine ionotropic (nicotinic) receptor facilitate the passage of through its channel?
Na+
In the nicotinic receptor, Na+ enters and excites the cell, leading to ____, and subsequent ____.
calcium release; muscle contraction
What happens when there is an influx of Ca2+ into the heart from an adrenergic response?
- Ca2+ excites the SA node, which increases heart rate
- Ca2+ accumulates in the muscle, so cardiac contractibility increases
___ is the major inhibitory neurotransmitter in the CNS, particularly in the brain.
GABA
____ synapses release neurotransmitters from the presynaptic membrane and bind to receptors on the post-synaptic membrane.
Chemical
What happens if SNAP-25 and syntaxin are cleaved?
no exocytosis can occur because fusion to the membrane cannot occur
Which neurotransmitters can be both excitatory and inhibitory?
acetylcholine
norepinephrine
Moving a cell’s charge closer to its threshold potential causes what kind of response?
EPSP (excitatory)
At rest, which ions are located extracellularly?
Na+
Ca2+
Cl-
Thyrotropin-releasing hormone, luteinizing hormone releasing hormone, and somatostatin are all released by the ____.
hypothalamus
____ is an extract that acts as an antagonist to the nicotinic receptor, blocking it.
Curare
____ is involved in movement, mood, and pleasure.
Dopamine
What are the ion concentrations of Cl- outside and inside the cell?
outside = 103 inside = 4
What happens when glutamate or glycine binds to the NMDA receptor for the glutamate Na+/Ca2+ channel?
both Ca2+ and Na+ rush into the cell (depolarizing and exciting it)
____ proteins are located in the synaptic vesicle and plasma membrane and help to dock vesicles and promote fusion of the layers for exocytosis.
SNARE
What constitutes a gap junction?
channels formed by connexons
____ is excitatory and associated with learning and memory.
Glutamate
____ open cation channels; ____ open anionic channels.
EPSP; IPSP
What does calcium activate when it enters the presynaptic cell?
synaptotagmin