In: Biology
Digitalis affects what protein?
A) potassium ion channels
b)ligand gated channels
c)sodium/potassium ATPase
d)calcium ATPase
e)sodium ion channels
Digitalis :-
• These are drugs of group cardiac glycosides.
• These drugs increase heart contractility, so these are used in
heart failure.
Mechanism of action :-
• This drug acts on sodium- potassium ATPase pump of heart
myocytes.
• Now this pump is unable to pump sodium ions outside the cell and
sodium ion concentration is increased in cell.
• This increased sodium ion concentration increases the activity of
sodium- calcium exchanger or calcium ATPase and it results into
increased calcium ion concentration in cell.
• Increased calcium increases contraction of muscle fibres and it
ultimately results into increased contractility of heart..
Now in question,
Option (c) is correct answer.
Sodium/ potassium ATPase pump.
Other options -
• Potassium ion channels are blocked by drugs like amiodarone,
dronedarone and bretylium.
• Ligand gated ion channels are transmembrane protein complexes and
their activities are controlled by neurotransmitters.
For example - Ion channels with nicotinic receptors are activated
by acetylcholine.
• Calcium ATPase activity is controlled by activity of sodium
potassium ATPase. ( *Explained above).
• Sodium ion channel blocker durgs are - Quinidine, procainamide.
These drugs are used as antiarrhythmic drugs.