QuestionSBA
QuestionChoice
This mechanism would lead to an increase in Na<sup>+</sup> reabsorption, and so would cause decreased water excretion (diuresis). Instead, thiazide-diuretics act in the distal tubule to inhibit the apical Na<sup>+</sup>/Cl<sup>-</sup>co-transporter. This leads to less Na<sup>+</sup> reabsorption from the tubule, thus leading to moderately increased Na<sup>+</sup> excretion with increased water excretion. This is diuresis.
10000727
b
Activates the apical Na<sup>+</sup>/Cl<sup>-</sup> co-transporter in the distal tubule
QuestionChoice
Thiazide diuretics act in the distal tubule to inhibit the apical Na<sup>+</sup>/Cl<sup>-</sup> co-transporter. This leads to less Na<sup>+</sup> reabsorption, thus leading to moderately increased Na<sup>+</sup> excretion with increased water excretion. This is diuresis.
10000726
a
Inhibits the apical Na<sup>+</sup>/Cl<sup>-</sup> co-transporter in the distal tubule
QuestionChoice
This is the mechanism of certain K<sup>+</sup>-sparing diuretics (e.g. spironolactone) which antagonise aldosterone receptors to then reduce Na<sup>+</sup> channel formation. This means that less Na<sup>+</sup> can be reabsorbed from the tubule - therefore causing greater Na<sup>+</sup> and water excretion. Meanwhile, thiazide-diuretics act in the distal tubule to inhibit the apical Na<sup>+</sup>/Cl<sup>-</sup> co-transporter. This leads to less Na<sup>+</sup> reabsorption from the tubule, thus leading to moderately increased Na<sup>+</sup> excretion with increased water excretion. This is diuresis.
10000728
c
Aldosterone receptor antagonist
QuestionChoice
This is the action of the weak K<sup>+</sup> sparing diuretics triamterene and amiloride. This mechanism leads to the inhibition of Na<sup>+</sup> reabsorption and decrease of K<sup>+</sup> excretion. Meanwhile, thiazide-diuretics act in the distal tubule to inhibit the apical Na<sup>+</sup>/Cl<sup>-</sup> co-transporter. This leads to less Na<sup>+</sup> reabsorption from the tubule, thus leading to moderately increased Na<sup>+</sup> excretion with increased water excretion. This is diuresis.
10000729
d
Blocks the luminal Na<sup>+</sup> channel in the distal tubule
QuestionChoice
This is the mechanism of carbonic anhydrase Inhibitors e.g. acetazolamide, which are early examples of weak diuretics, and are not often used for diuresis. Thiazide-diuretics, however, act in the distal tubule and inhibit the apical Na<sup>+</sup>/Cl<sup>-</sup> co-transporter. This leads to less Na<sup>+</sup> reabsorption from the tubule, thus leading to moderately increased Na<sup>+</sup> excretion with increased water excretion. This is diuresis.
10000730
e
Blocks NaHCO<sub>3</sub> reabsorption in the proximal tubule
Concept
Chapter
2693
3815
Thiazide diuretics
Topic
169
Cardiovascular pharmacology
12692
Which of the following options best describes the mechanism of action of thiazide diuretics?
a