14: Purines Flashcards
3 types of purines
adenosine
ATP/ ADP
methylxantines
endogenous purines are involved in
DNA/ RNA synthesis
energy metabolism
purinergic signalling
3 families of purinergic receptors
- adenosine receptors- GPCR
- P2Y (1-14)- GPCR
- P2X - ATP gated cation channels
where is adenosine found
cell cytosol and body fluids
cardiovascular effects of adenosiene
inhibits cardiac conduction
vasodilation
inhibits platelet aggregation
CNS effects of adenosine
inhibitory- on neurons
caffeine vs adenosine
inhibits adenosine’s inhibitory effects = stimulant
adenosine inflammatory effects
pro (A1) anti (A2 promotes mediator release form mast cells enhances mucous secretion in lungs bronchoconstriction leurkcyte activation
does adenosine inhibit or promote mediator release form mast cells
promote
does adenosine cause bronchodilation
inhibit- causes bronchoconstriction
theophylline treats _____ by
asthma by blocking A1
methylxanthines treat ___ by
asthma by blocking phosphodiesterase actions = increase in cAMP = SMC relaxation = bronchodilation
where is ADP usually found
cell vesicles and are exocytosed
what is ADP’s primary receptor
P2Y
what sitmulates platelet aggregation by P2Y
ADP
ATP acts on
P2X
which is found in the cell in high concentrations ATP or ADP
ATP
ATP can be released by
exocytosis or channels
what regulate K+ channels to stimulate vasodilation
ATP
ATP stimulates insulin ____ at low concentrations. It ____ insulin secretion at high concentrations by _____ _____ hyperpolarization
secretion
decreases
beta cell
ATP is important for ___ transmission and is a NT in the ____
pain
periphery
what is released from dead/ dying cells + stimulates neutrophil chemotaxis for inflammation mediation
ATP