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