calcium channel blockers

how is cardiac output maintained

• by cardiomyocyte contraction

• drives blood out of heart

what are the type of calcium channels involved in muscle contraction

L-type calcium channels

what do L-type calcium channels do

regulate calcium entry into smooth muscles

what does calcium activate

smooth muscle contraction

how many calciums bind to calmodulin

4 Ca2+ bind to 1 calmodulin

what does increased calcium stimulate

contraction

what happens when calcium binds to calmodulin

• MLCK activated and myosin is phosphorylated

• active force- output

what happens when calcium binds to telokin

• MLCP activated and myosin phosphorylated 

• active force-output

what does smooth muscle contraction stimulate and increase

• stimulate vasoconstriction

• increases blood pressure 

what are calcium channel blockers also known as

calcium antagonists 

what do calcium antagonists inhibit 

inhibit the influx of Ca2+ through L-type voltage-gated calcium channels 

what is Ca2+ fundamentally involved in

• contraction of smooth muscle 

• Ca2+ moves into the smooth muscle cells via L-type Ca2+ channels 

how many classes of L-type antagonists are there

3

what are the 3 classes of L-type antagonists

• dihydropyridines

• phenylalkylamines

• benzodiazepines

what is an example of dihydropyridines and what are they selective for

• nifedipine/amlodipine

• selectivity for L-type VGCCs in the vascular smooth muscle

what is an example of phenylalkylamines and what is it selective for 

• verapamil

• selectivity of L-type VGCCs in the heart 

what is an example of benzothiazepines and what is their selectivity

• diltiazem

• intermediate selectivity

what are calcium antagonists effective at

• lowering blood pressure mainly via vasodilatory effect, decreasing TPR

• decreased contraction of cardiomyocytes 

what are calcium antagonists also used in the treatment of 

• angina 

• dilate coronary arteries and are antidysrythmics