UCBEX PHARM Module 6

Increasing the formation of cyclic GMP

Vasodilation by nitroglycerin and other organic nitrates, such as isosorbide mononitrate, occur as a result of what molecular event?

Increase contractile force more than heart rate

Dobutamine an adrenergic β1 receptor agonist is utilized to treat heart failure. Although the exact mechanism remains unknown, it is useful because of its ability to do what?

True

Verapamil is not used therapeutically to treat heart failure. T or F

False

The sinoatrial node, the main pacemaker of the heart, creates an action potential via continual stimulation from the sympathetic or parasympathetic pathway. T or F

False

Angiotensin II is a vasodilator. T or F

All of the above

In vascular smooth muscle cells

1. Depolarization of the membrane allows Ca2+ entry via voltage-gated channels

2. Inositol triphosphate, a product of phospholipase C activation, releases intracellular Ca2+ from the sarcoplasmic reticulum

3. Ca2+ combines with calmodulin to activate myosin light-chain kinase

4. Depolarization of the membrane allows Ca2+ entry via voltage-gated channels and Ca2+ combines with calmodulin to activate myosin light-chain kinase

Acetazolamide

Which of the following pharmacological agents inhibits carbonic anhydrase?

Hypokalemia

Large doses of hydrochlorothiazide can cause which of the following?

Blocking apical sodium channels

The diuretic effect of amiloride is due to which of the following?

Furosemide

Which of the following pharmacological agents inhibits the Na+/K+/2Cl- transporter?

Endothelin receptor antagonist

Bosentan is a vasoactive drug utilized clinically to treat pulmonary hypertension as an

A delayed influx of Ca2+, which balances a slowly increasing efflux of K+

The plateau phase (phase 2) of an action potential observed in non-pacemaker cardiac cells is a result of which of the following?

Minoxidil

Of the following pharmacological agents, the activation of K+ channels in vascular smooth muscle mediates vasodilation?

Phosphodiesterase inhibition elevating cGMP levels

The ability of Sildenafil to promote blood flow depends on which of the following?

Nitric oxide production

Bradykinin is a vasodilator by stimulating which of the following?

CO, PVR, LVSV

Blood pressure is regulated by

Increased intracellular calcium

A delayed after-depolarization event occurs as a consequence of

Class I

Lidocaine belongs to what class of antiarrythmic (antidysrhythmic) drugs?

Decrease cardiac oxygen consumption

Nitroglycerin, besides reducing coronary artery spasm and redistributing blood to ischemic areas of the heart, is utilized therapeutically to treat stable angina due to the ability to do which of the following?

Atrial fibrillation

Which of the following arrhythmias is verapamil utilized for?

Clonidine

Of the following pharmacological agents, which diminishes the firing of sympathetic neurons by exerting its effects within the central nervous system?

Digoxin inhibits the Na/K/ATPase membrane pump. Hypokalemia from diuretics in addition to digoxin can cause decreased intracellular potassium concentrations at an alarming level.

Why should a diuretic that decreases plasma K+ levels not be used with digoxin?

Furosemide increases the delivery of sodium to the distal portion of the nephron resulting in the loss of protons and potassium ions. Spironolactone inhibits the action of aldosterone, limiting reabsorption of sodium and can help prevent hypokalemia.

What are the benefits of co-administering furosemide with spironolactone?

Captopril competes with angiotensin 1 for binding to ACE and inhibits enzymatic proteolysis of angiotensin 1-->angiotensin 2, decreasing angiotensin 2 levels and therefore decreasing blood pressure.

ACE inhibitors prevent the breakdown of bradykinin and substance P which results in an accumulation of protussive mediators in the respiratory tract- causing a dry cough.

Explain the mechanism of action of captopril. ACE inhibitors produced a dry cough as unwanted side effect. Explain the existence of a dry cough following the administration of an ACE inhibitor.

When blood flow to the kidneys is reduced, juxtaglomerular cells in the kidney convert prorenin to renin, which is then secreted into the circulation. Plasma renin converts angiotensinogen --> angiotensin 1 --> angiotensin 2 (via ACE). Angiotensin 2 is a potent vasoconstrictor, which causes vessels to narrow and in turn raises BP and CO. Angiotensin 2 also causes increases in sodium and water reabsorption in renal tubules, which increases extracellular fluid and increases BP which increases CO.

Explain the renin angiotensin aldosterone system and how the signaling pathway results in an increase in cardiac output. Start with the release of renin from the juxtaglomerular apparatus.