Neurotransmitters Flashcards
(32 cards)
What is an ionotropic receptor?
receptor protein that HAS an ion channel that opens when the receptor is bound
What is metabotropic receptor?
receptor protein that DOES NOT HAVE an ion channel but when activated, may utilize a second-messenger system to open nearby ion channels or produce other cellular effects
Example of ionotropic receptor?
GABA receptor
Example of metabotropic receptor?
G protein coupled receptor
What are the principles of neurotransmitters?
1) It is SYNTHESIZED by presynaptic neurons
2) RELEASED when AP reach the terminals
3) RECOGNIZED by specific receptors on postsynaptic membrane
4) causes CHANGES in postsynaptic neuron
5) BLOCKING its release interferes with ability of the presynaptic neuron to affect the postsynaptic neuron
What is amino acid neurotransmitter?
most abundant, neurotransmitters that is an amino acid (GABA, glutamate)
What is glutamate?
Amino acid neurotransmitter; most widespread EXCITATORY ntrans in brain; plays role in synaptic plasticity (cognitive function like learning and memory); involved in long term potentiation (persistent strengthening of plasticity)
What is GABA?
amino acid ntrans, most widespread INHIBITORY ntrans in brain; muscle relaxation, sleep induction
Synaptic delay?
Brief delay between the arrival of AP at presynaptic axon terminal and creation of postsynaptic potential; time it takes for voltage-gated Ca+2 ion channels to open, Ca+2 to get in, and synaptic vesicles to fuse with membrane
Synaptic vesicles?
small sphere structures containing molecules of ntrans, located in presynaptic axon terminal and fuse with membrane to release ntrans
Synaptic cleft?
Space between presynaptic and postsynaptic cells at a synapse; where ntrans is released into
What is degradation?
transmitter molecules rapidly broken down and inactivated by specific enzymes
What is reuptake?
transmitter molecules taken back up into presynaptic terminal and reused
What is a transporter?
Specialized membrane component that returns transmitters to presynaptic terminal for reuse
What is first thing that happens in a synaptic action?
Action potential arrives and spreads over membrane (presyn)
What happens after the action potential in the process?
Voltage gated Ca2+ channels open (pre)
What happens after Ca2+ channels open?
Synaptic vesicles migrates to presyn membrane, fuse, rupture –> release ntrans into synaptic cleft (synaptic space)
What happens after the ntrans leave the presynaptic membrane?
Ntrans bind to postsynaptic receptors (post)
What happens after ntrans bind to postsynaptic receptors?
Sends IPSP or EPSP across cell membrane, then STOP and report back (sometimes)
What is acetylcholine? (Ach)
amine ntrans; found in basal forebrain = major source of cholinergic projections in the brain (referring to nrns that use this as their synaptic transmitter); widespread loss associated with Alzheimer’s; nicotinic receptors, others
What is dopamine (DA)?
found in midbrain + basal forebrain; 1 million out of 80 billion neurons produce it
What is mesostriatal pathway?
dopaminergic projection that originates in midbrain around substantia nigra + projects to regions of basal ganglia; important in motor control
Substantia nigra?
brainstem structure that innervates basal ganglia and is major source of dopaminergic projections
Mesocorticolimbic pathway?
dopaminergic projection that originates in the midbrain around the ventral tegmental area + projects to various locations
