L22-24 Alpha and Beta Receptors Flashcards Preview

Pharmacology Fall 2015 > L22-24 Alpha and Beta Receptors > Flashcards

Flashcards in L22-24 Alpha and Beta Receptors Deck (11):
1

Function of alpha 1 receptors

Vascular smooth muscle constriction
Contraction of base of bladder, sphincter muscle, and prostate
Mydriasis
Ejaculation

2

Effects of alpha 1 blockade

Decreased peripheral vascular resistance causing dec BP and venous return, orthostatic hypotension
Miosis
Nasal congestion
Easier urine flow from relaxed base of bladder, urethra and prostate
Inhibition of ejaculation

3

Function of alpha 2 receptors

decrease NE release, contract some vascular SmM

4

Effects of alpha 2 blockade

increased NE release, increased sympathetic output, increased BP

5

Functions of beta 1 receptors

inc rate and force of heart contraction
inc automaticity of heart
increase renin secretion

6

Functions of beta 2 receptors

relax bronchioles
dilate some BV's
increase glycogenolysis
increase production of aqueous humor and intraocular pressure

7

Functions of beta 3 receptors

increase lipolysis

8

How does a dose response curve change with use of a competitive inhibitor?

Shift is usually parallel if acting on same receptor

9

How does a dose response curve change with a non-competitive inhibitor?

Max response is lower, curves not parallel

10

Name the alpha receptor blockers

Reversible: phentolamine, prazosin, terazosin, doxazosin, tamsulosin, alfuzosin, labetalol
Irreversible: phenoxybenzamine
Alpha 2 selective: yohimbine

11

Phentolamine

Competitive alpha 1 and 2 antagonist
Decreases peripheral resistance and BP–especially diastolic
May increase HR
Alpha 2 block increases NE on heart and low BP stimulates baroreceptors
Also stimulates gastric acid secretion