sem B - beta blockers, treatment of cardio disease Flashcards
what does B1 receptor do
increase heart rate and force of contraction, release of renin from kidney
what does B2 receptor do
smooth muscle relaxation - bronchodilation, vasodilation, relaxation of uterus and bladder wall
what does B3 receptor do
increase lipolysis in adipose tissue, relaxation of bladder wall
B1 adrenoreceptor signalling - B1 adrenoreceptor activates G protein, that activates adenylyl cyclase converting ATP to …. that activates PKA
cAMP
…. channel activated which carries pacemaker currents (funny current)
HCN channel
….. channel activated which is phosphorylated as a result of PKA
L type Ca2+ channel
B1 adrenoreceptor activation on SA node pacemaker - positive chronotropic effect
increase heart rate - faster depolarisation from greater HCN activity
B1 adrenoreceptor activation on cardiac contraction - positive inotropic effect
increased cardiac contraction due to increased Ca2+ entry into cell
artherosclerosis - build up of cholesterol plaques in the
coronary arteries
artherosclerosis - restricted or sufficient blood supply
sufficient blood supply maintained, no symptoms
angina - restricted or sufficient blood supply
restricted blood supply, increased O2 demand
in a normal blood vessel during stress/exercise …… increases oxygen supply as there is a higher demand
vasodilation
angina - during stress/exercise - increased/decreased supply but higher demand because there’s no vasodilation
decreased supply
blocking B1 receptors by beta blockers (propanolol) -
negative chronotropic and inotropic effect on heart
beneficial effect of blocking B1 receptors (1,2)
-reduces CO by reducing positive inotropic/chronotropic effects of SNS
-reduces renin secretion, reduced blood vol
–> DECREASED BP
