P2X receptors and acid-sensing ion channels Flashcards
How many subunits compose a P2X receptor?
3
P2X receptors are permeable to ?
Na
K
Ca
some Cl (depends on subunits)
what is dominant among the P2X receptors
homo-oligimers or hetero-oligomers
homo-oligomers
P2X receptors are
ligand gated ion channels
P2Y receptors are
G protein coupled receptors
what P2X receptors are hetero-oligomeric
P2X2 P2X3
NH3 attaches at ____ terminus
COO attaches at ____ terminus
N
C
role of lateral pores in P2X receptor
facilitate flow of cations
what gates P2X receptors ?
ATP
cellular damage has what effect on ATP
triggers vesicular release of ATP
ATP is converted to ADP
name the agonist for P2X receptor
ATP
name an antagonist for P2X recptors P2X1,P2X2, P2X3 + P2X5
suramin
how are P2X receptors allosterically modulated
changes in pH
P2X receptors are involved in _______________ transmission, _____________ function, ______________ in the gut, ___________ function, ____________ tone
synaptic cardiac excitation kidney vascular
P2X receptors are also involved in _________ and _______________ responses
apoptosis
inflammatory
location and function of P2X1
smooth muscle and bladder
bladder contraction
location and function of P2X2, P2X3, P2X2/3
nervous system, sensory neurons
taste perception
location and function of P2X4
central NS
neuroinflammation
location and function of P2X5
B and T cells
inflammation
Cl conductance
location and function of P2X6
B cells
pro-inflammatory immune response
location and function of P2X7
lots of tissues
inflammation
acid-sensing ion channels are gated by
hydrogen ions
name the ligand for ASICs
hydrogen ions
how many subunits are there in ASICs
3 (trimer)
what blocks ASICs
amiloride
where are ASICs expressed and what do they modulate
in CNS and PNS
modulate neuronal sensitivity to acidosis
what other type of channel is ASICs related to
ENaC
also blocked by amiloride
name the ASIC receptors
ASIC1a and ASIC1b
ASIC2
ASIC3
ASICs are activated by
changes in pH
what do P2X receptors lack ?
selective ligands
