CNS Flashcards
What amino acid are dopamine, norepinephrine, and epinephrine derived from?
Tyrosine (Tyr, Y)
What are three possible pathways that dopamine, norepi, and epi can take in the post-synaptic cleft?
- re-uptake into the neuron and metabolized
- bind to post-synaptic receptor
- bind to autosynaptic receptor to inhibit signal
What amino acid is serotonin derived from?
Tryptophan (Trp, W)
What is another name for serotonin?
5-hydroxytryptamine (5HT)
What converts dopamine to norepinephrine?
dopamine-beta-hydroxylase
What converts norepinephrine to epinephrine?
phenylethanolamine N-methyltransferase (PNMT)
What is direct action of a neurotransmitter?
the neurotrasmitter binds to and opens ion channels - elicits rapid response
What is indirect action of a neurotransmitter?
the neurotransmitter acts through intracellular secondary messengers (usually G-proteins) to open ion channels - longer and broader response
What is the difference between voltage-gated and ligand-gated membrane channels?
voltage-gated open/close in response to voltage changes across the membrane (potential) :: ligand-gated open/close in response to a molecule binding to the channel
Difference between ionotropic and metabotropic receptors?
Ionotropic = direct ligand binding to open channel Metabotropic = indirect/secondary messenger signal to open channel
What are the two types of metabotropic receptors?
Membrane-delimited: all secondary messenger molecules are entirely in plane of membrane (think attached to membrane)
Diffusible second messengers: messenger molecules travel through cytoplasm to get to target
What are autoreceptors?
Receptors on an axon terminal that the axon’s own transmitter can bind to elicit a response on that axon (usually inhibitory)
What are heteroreceptors?
Receptors on an axon terminal that recieves transmitters from other axons
What are the three catecholamines?
dopamine, norepinephrine, and epinephrine
What are two amino acid transporters?
GABA & Glutamate
What is acetylcholine derived from?
Choline brought into the neuron by choline transporter
Why must ACh be made from choline?
Because there is NO transporter that will transport ACh across a membrane, so choline is brough into cell to make ACh
What kind of receptor can ACh bind?
nicotinic or muscarinic
What metabolizes ACh into choline on the post-synaptic cell?
Acetylcholinesterase
What benefit does an astrocyte provide for Glutamate levels?
Astrocytes help metabolize and regulate Glu levels
What is Glu derived from in neuron?
alpha-Ketoglutarate
What three receptors can Glu bind post-synaptically?
Kainate, NMDA, or AMPA
What does an astrocyte do with Glu?
Metabolize it into Glutamine (Gln)
What is GABA derived from?
Glutamate (Glu)
What is GABA made into inside the astrocyte?
succinate
What enzyme converts Glu to GABA?
Glutamate decarboxylase
What kind of post-synapse receptors does GABA bind?
Either GABA-alpha or GABA-beta
What do mu-receptors do to GABA concentration?
They inhibit GABA production and release
What is an endorphin?
A mu-receptor ligan that can inhibit GABA release
