Flashcards in 04a: NT and Neuromodulators Deck (50):
List the three main types of signal transduction pathways in plasma membrane receptors.
1. Ligand-gated channel (ionotropic)
2. G-Protein with second messenger production
3. G-protein with control of ion channel
G-Proteins can couple receptor to:
1. Ion channel
2. Effector protein
G(s) is activated. What's its immediate effect?
Activates adenylyl cyclase
Adenylyl cyclase is activated by which specific G-protein? What's AC's function?
Produces cAMP (second messenger) from ATP
cAMP action is terminated by (X).
X = hydrolysis via PDE
G(c) is activated. What's its immediate effect?
Activates guanylyl cyclase
Guanylyl cyclase is activated by which specific G-protein? What's GC's function?
G(i) is activated. What's its immediate effect?
Inhibits adenylyl cyclase
G(q) is activated. What's its immediate effect?
PLC is activated by which specific G-protein? What's PLC's function?
Produces second messengers (IP3 and DAG)
Odorants activate (X), which causes (increase/decrease) in (Y), which causes (increase/decrease) in (Z). Hence, (de/re/hyper)-polarization of olfactory receptors.
X = G(olf) G-protein
Y = cAMP concentration;
Z = permeability to Na and Ca
List mechanisms that cause cessation of activity caused by G-proteins.
1. 2nd messengers inactivated
2. Phosphorylation/altering of receptors (less affinity for ligand)
3. Receptor-NT complexes removed via endocytosis
List the biogenic amines.
List two examples of catecholamines.
NE and DA
Enkephalin falls into which NT category? Name another NT that belongs in this category,
Neuroactive (Opioid) peptides
List some gases that act as NT.
NO and CO
List purines that act as NT.
ATP and adenosine
Somatic NS uses (X) NT receptor. Its activation causes
X = nicotinic ACh
Increase in gNa, gK, gCa (depolarization)
Binding of (X) to D1 receptors causes (increase/decrease) in which ion/messenger?
X = DA;
Increase in cAMP through G(s)
Binding of (X) to D2 receptors causes (increase/decrease) in which ion/messenger?
X = DA
Decrease in cAMP through G(i)
Which NT is considered the messenger for pleasure and reward?
Cocaine (stimulates/inhibits) the reuptake of (X), thus reinforcing its action.
X = DA
Glutamate reacts with (metabotropic/ionotropic) receptors
List the receptor subtypes that act as ion channels activated by glutamate.
NMDA channel is (blocked/unblocked) at Vm and is (blocked/unblocked) at (X) mV. By what?
X = -60 (or more positive)
T/F: A signal that opens AMPA channel will always open NMDA channel.
False - NMDA also voltage-dependent
GABA is formed from (X).
X = Glutamate
List GABA receptors. Star the ones that are metabotropic
GABA(a) and GABA(b)*
Activation of GABA(a) receptor causes (increase/decrease) in
gCl (opposes depol)
Activation of GABA(b) receptor causes (increase/decrease) in
Decreases gCa and increases gK (via Gi)
Glycine primarily acts by (increasing/decreasing) (X) conductance in (brain/SC).
X = Cl
List examples of NTs in the class of neuroactive peptides.
1. ADH and oxytocin
2. CCK and VIP
3. Substance P
4. Opioid peptides
T/F: Only neurons release NO.
False - endothelial cells too
NO mechanism is to (increase/decrease) (extracellular/cytosolic) which ion/second messenger?
ATP and adenosine act as (stimulatory/inhibitory) transmitters in autonomic NS.
ATP and adenosine act on (G-protein/ligand-gated) receptors.
In G-proteins, the alpha subunit is bound to (receptor/beta-gamma/GDP/GTP) when interacting with effector proteins.
Bound to GTP
In G-proteins, which component is a GTPase? What occurs when it hydrolyzes GTP?
converts it back to inactive state (GDP-bound)
Which ACh receptors are found in abundance in CNS? They use the (X) messenger system - causing increase/decrease in conductance of which ion(s)?
M1 metabotropic receptors;
X = IP3
Increase gCa and decrease gK
Serotonin is produced from (X) and broken down by (Y).
X = tryptophan;
Y = oxidization by MAO
Hallucinogenic agents, such as (X), are (Y) (agonists/antagonists).
X = LSD;
Y = serotonin;
Serotonin binds to (X) receptors. All are (ionotropic/metabotropic).
X = 5-HT
Most metabotropic (GPCRs) except one
Histamine receptors are found in which location(s)?
Peripheral tissues and brain
Glu and Asp serve as NT at vast majority of (inhibitory/excitatory) synapses in (CNS/PNS).
Main excitatory NT in brain.
Glu (metabotropic/ionotropic) receptors involved in synaptic plasticity.
Main inhibitory NT in brain.
GABA is formed from:
Barbiturates/benzos are meds for (X). What's the Mechanism?
X = reducing anxiety/relaxing muscles
Enhance GABA(a) effect on gCl