Receptor Families Flashcards
What is the mechanism of strychine?
competitive inhibitor of glycine channels
List the receptor families in order of fastest to slowest desensitization.
- ligand gated (AMPA is fastest)
- GPCR (B arrestin leads to internalization of GPCR receptors)
- RTKs
- cytoplasmic glucocorticoid
receptors
What is the difference between cys loop families and non cys loop families?
have 5 subunits with four membrane spanning domains
cys loop families have a loop of 13 AAs held together by cysteine in alpha subunit
What is the mechanism of Zolpidem?
not benzodiazepine, but allosteric activator of GABAa used to induce sleep
What RTK pathway do cytokines use and what are the results?
JAK/STAT pathway, increases gene transcription and coordinates immune response
What is the mechanism of drugs with -sons or -ones suffix?
activates cytoplasmic glucocorticoid receptors
Why is Zolpidem Swati’s favorite drug?
because it induces sleep and is effective for years (as an allosteric activator)
What is the mechanism for drugs with a -setron suffix?
competitive inhibitor of serotonin 5-HT3 channels used to treat nausea and vomiting
Which receptor desensitizes the fastest?
AMPA
What is the mechanism of drugs with an -azepam and -azolam suffix?
benzodiazepines (ex: diazepam) are allosteric activators of GABAa receptors that are used to treat anxiety
What are the four excitatory ligand gated receptors?
nicotinic, serotonina 5-HT3, P2X ATP and Glutamate
List the receptor families from fastest to slowest.
ligand gated channels
GPCRs
tyrosine kinases (RTKs)
cytoplasmic/nuclear receptors
How do GPCRs lead to relaxation of smooth muscle and contraction of cardiac muscle?
activation of a3 G protein which activates adenylyl cyclase which activates cAMP which activates PKA and leads to protein phosphorylation
What is the mechanism of tetanus toxin?
blocks pre synaptic release of glycine
What are the good and bad consequences of NMDA receptor activation?
at normal levels, mediates learning and memory
at very high levels, there is excess Ca2+ that leads to excitotoxicity and diseases like Alzheimer’s
What is the mechanism of the glucocorticoid receptor?
- steroid diffuses into cell and binds cytoplasmic glucocorticoid receptor
- receptor was bound to HSP90, which inhibited it but releases HSP90 upon binding of steriod
- steroid/receptor dimerizes and goes to nucleus causing changes in gene transcription
What RTK pathway do growth factors use and what is the result of the pathway?
RAS/MAPK pathway which leads to increase in transcription ultimately resulting proliferation, wound healing, adhesion and migration
What is the mechanism of memantine?
uncompetitive inhibitor of NMDA receptors to treat diseases like Alzheimer’s by blocking intake of Ca2+
Describe the inhibitory motif of GPCRs
subscript of 2 is used
By: stimulates K+ or inhibits Ca2+
alpha i: inhibits adenylyl cyclase
leads to neurotransmitter release
What RTK pathway does insulin use and what are the results?
mainly PI-3/AKT/mTOR pathway which increases translation to increase fuel uptake and storage
How do GPCRs lead to contraction of smooth muscle?
subscript of 1 or 3 is used
a2 G protein activated PLC which causes synthesis of IP3 leading to Ca2+ release and smooth muscle contraction
What are the two types of glutamate ligand channels?
non-NMDA (AMPA) and NMDA
How does AMPA function?
mediate fast excitatory synaptic transmission in CNS, non-selective ligand gated Na+ channels
What type of drug does not lead to quick desensitization?
allosteric activators
