CaV And Hypertensio

Question 1

Types of CaV channels

Answer 1

• L-type (CaV1) -> 1.1, 1.2, 1.3, 1.4
• P/Q-type (CaV2.2)
• N-type (CaV2.1)
• R-type (CaV2.3)
• T-type (CaV3)
• L-type consists of 4 genes encoding
different α1 subunits

Question 2

What is Ca2+ important for

Answer 2

Cardiac and smooth muscle contraction

Question 3

L-type Ca channels

Answer 3

(CaV1.2 and CaV1.3)
Found in the heart ad in vascular smooth muscle

Drugs acting on these can be used to control heart rate and vascular tone (dampe done the CaV)

They are Ca channel blockers - antagonists

Question 4

Pharmacology of CaV Chanel’s

Answer 4

• Phenylalkylamines – verapamil - preferential for heart
• Dihydropyridines – nifedipine - preferential for hypertension
• Benzothiazepines - diltiazem

These drugs can cause AV block and cardiac slowing
These drugs can induce arteriolar dilatation and reduce blood pressure – act as vasodilators
Side effects – flushing, headaches, ankle swelling, cardiac rhythm, constipation
Linked to blocking CaV channels in other locations

Question 5

CCB

Answer 5

Ca channel blockers

Bind to a1 subunit

interfere with voltage-dependent cycling between
resting –> open–> inactivated states

Higher affinity binding occurs to the open state or inactivated state

IIIS5, IIIS6 and IVS6 segments are major areas of drug binding