lecture 6 - sympatholytics/adrenergic modulators Flashcards
What type of receptors are acted on by sympathetic nerves in the heart?
Beta-1 receptors
What type of receptors are acted on by parasympathetic nerves in the heart?
Muscarinic receptors
What type of receptors are acted on by sympathetic nerves in blood vessels?
Alpha receptors
What type of receptors are acted on by sympathetic nerves in the lungs?
Beta-2 adrenergic receptors
What is the first line drug treatment for hypertension?
ACE inhibitors (can also use calcium channel blocker or thiazide diuretic)
What is a commonly prescribed Alpha 1 blocker/antagonist?
Doxazosin
What is the key indication for doxazosin?
Hypertension (though generally not to be used as a monotherapy)
What is the mechanism of action of doxazosin?
Inhibits alpha-1-adrenoreceptors therefore producing a vasodilatory effect and drop in TPR reducing blood pressure
What are the indications for alpha-2 agonists, such as clonidine?
hypertension
What is the receptor specificity of 1st generation Beta blockers?
B1 and B2
What is the receptor specificity of 2nd generation Beta blockers?
B1
What is the receptor specificity of 3rd generation Beta blockers?
B1, B2, a1
What is the pharamacological action of Beta-blockers?
They antagonise cardiac and renal Beta-adrenoreceptors
What are the effects of Beta-blockers on the heart?
Negative chronotropic (decrease rate of contraction),
Negative inotropic (decreases force of contraction)
What causes the anti-hypertensive effects of Beta-Blockers?
Reduced cardiac output, which reduces MABP, also reducing RAAS activation.