Adrenergic Pharmacology 3

Question 1

What are the pharmalogical uses of beta blockers?

Answer 1

• Prevent stimulation of the sympathetic nervous system by inhibiting the action of catecholamines at the beta-adrenergic receptors (beta-blockers)
• Heart attack, angina, hypertension, hypertrophic, cardiomyopathy, supraventricular arrhythmias

Question 2

What are the uses for non-selective beta blockers?

Answer 2

• Affect β1 receptor sites located mainly in the heart and β2 receptor sites located in the bronchi, blood vessels and uterus

Question 3

What are the major Adverse effects of Beta blockers?

Answer 3

• dizziness
• light-headedness
• fatigue

Question 4

What are the functions of β1 receptors of the heart and β2 receptors in the airways?

Answer 4

• Both receptors cause increase in cAMP
  
  • cAMP has different effects:
    
    • PKA activates Ca2+ channels (causing constriction)
    • cAMP directly blocks MLCK activity (causing relaxation)
  • Increased cAMP by β2 agonists directly inhibit myosin light chain kinase thereby producing relaxation (vasculature)

Question 5

Describe heart function related terms

Answer 5

• β1 is most important adrenoreceptor in heart
  
  • when activated by a β1 agonist such as NA or A
    
    • heart rate increased (positive chronotropy)
    • conduction velocity increased (positive dromotropy)
    • contractility increased (positive inotropy)
    • rate of myocyte increased (positive lusitropy)

Question 6

Does β1 stimulation lead to constriction or relaxation?

Answer 6

Constriction

Question 7

Does β2 stimulation lead to constriction or relaxation?

Answer 7

Relaxation