Neurotransmission 2 - Kenyon Flashcards
How many families of neurotransmitter receptors are there? What are they called?
4 families
- Ionotropic ligand gated ion channels
- Tyrosine kinase enzyme-linked receptors
- G-protein coupled receptors (GPCRs)
- Intracellular receptors for unconvential neurotransmitters.
What is the difference between ionotropic and inotropic?
Ionotropic: single transmembrane protein binding a neurotransmitter that acts as the channel for cation movement.
Inotropic: ability of muscle to generate force at a given length.
Are ionotropic receptors made from a specific set of subunits or a combination?
A combination of many!
What the ionotropic receptors for glutamate? (3)
- AMPA
- NMDA
- Kainate
Do GPCRs directly or indirectly influence opening/closing of ion channels?
Both!
Are GPCRs 1TM or 7TM?
1TM
Can GPCRs elicit multiple intracellular effects?
yes!
What is an orphan receptor?
A 7TM receptor that looks like a metabotropic receptor but the neurotranmisster is unknown.
Describe the function of a metabotropic (GPCR) receptor?
- Nuerotransmitter binds.
- g-protein activated
- G protein subunits or intracellular messengers modulate ion channels
- Ions flow across membrane
- Ion channel opens.
Describe the function of an ionotropic receptor?
- neurotransmitter binds
- Channel opens
- Ions flow across the membrane.
Can you form an ionotropic receptor by mixing and matching subunits?
Yes! Can make hundreds of receptors from subunit pool.
Are there many or few metabotropic receptors?
Few, <10
Do ionotropic receptors have a limited or extensive set of intracellular responses?
What is the primary effect?
Limited response, mostly changes membrane potential.
Allowing (blank) ions through an ionotropic receptor will increase the number of intracellular effects?
Calcium!
Do metabotropic receptors have limited or extensive intracellular effects?
“UNLIMITED” biochemical responses!
GPCR->signaling cascade systems
Activation of a (blank) receptor will change a neuron’s likelihood of firing an action potential
Metabotropic
Why does Ca influx alter the function of ionotropic receptors?
Calcium is central in all vitally controlled cell processess–death, growth, continuation of life, etc.
Do tyrosine kinase enzyme linked receptors directly or indirectly open and close ion channels?
Indirectly!
Enzyme-LINKED
The (blank) enzyme involved in nitric oxide synthesis dependent on (blank) ions.
NO synthase
Calcium
What are the four general groups of small molecule neurotransmitters?
- ACh
- Amino acids
- Biogenic amines
- Purines
What are the amino acid NT’s? (4)
- Glutamate
- Aspartate
- GABA
- Glycine
What are the biogenic amines (3)?
- Catecholemines (NEpi, Epi)
- Serotonin (5-HT)
- Histamine
What are the purines (4)?
ATP, ADP, AMP, Adenosine
Gastrin releasing peptide is involved in remembering (blank).
Fearful situations
What is the general postsynaptic effect of ACh?
Excitatory
What is the general postsynaptic effect of glutamate?
Excitatory
What is the general postsynaptic effect of GABA?
Inhibitory
What is the general postsynaptic effect of glycine?
Inhibitory
What is the general postsynaptic effect of catecholemines?
Excitatoryo
What are the precursors to ACh?
Choline, acetyl CoA
what is the rate limiting step in ACh synth?
CAT
How is AcH removed?
AChEase
How are glutamate, GABA, glycine removed?
Transporters
How are catecholemines removed?
Transporters and MAO
What is the general postsynaptic effect of 5-Ht?
Excitatory
What is the general postsynaptic effect of Histamine?
Excitatory
What is the general postsynaptic effect of ATP?
Excitatory
What is the general postsynaptic effect of neuropeptides?
Excitatory and inhibitory
What is the precursor to 5-Ht?
Tryptophan
What is the rate limiting step in 5-HT synth?
tryptophan hydroxylase
How is 5-Ht removed?
Transporters and MAO
How is histamine removed?
Transporters
What is the precursor to ATP?
ADP
How is ATP removed?
Hydrolysis to ADP and adenosine
What are the precursors to neuropeptides?
amino acids
How are neuropeptides removed?
proteases
What are the precursors to endocannabinoids?
Membrane lipids
what is the rate limiting step for endocannibinoids?
enzymatic mod of lipids