24 Questions
What is the reason noncatecholamines have a longer half-life compared to catecholamines?
They lack a catechol group, making them substrates for COMT and metabolize slowly by MAO.
At low doses, what is the receptor specificity of albuterol?
Acts on B2 receptors only
What effect does activation of alpha-1 receptors produce?
Vasoconstriction in blood vessels of the skin, viscera, and mucous membranes
What is the primary therapeutic application of drugs acting on beta-1 receptors?
Treatment of shock
What adverse effect can be caused by overstimulation of B1 receptors?
Tachycardia and dysrhythmias
What is the therapeutic application of drugs acting on B2 receptors?
Treatment of asthma
Why are most asthma medications inhaled medications?
To reduce adverse effects
What is the primary therapeutic effect of dopamine receptor activation?
Improving renal perfusion
What effect does activation of alpha-2 receptors in the central nervous system have?
Reduction of sympathetic outflow to the heart and blood vessels
What is the adverse effect associated with activation of B2 receptors?
Tremor
How do noncatecholamines differ from catecholamines in terms of oral administration?
Noncatecholamines can be given orally as they do not undergo rapid degradation by MAO and COMT like catecholamines.
What causes the pink or brown pigmentation in catecholamine-containing solutions over time?
Oxidation of the catecholamine molecule
What is the primary mechanism of action for adrenergic agonists?
Direct or indirect activation of adrenergic receptors
Which class of adrenergic agonists includes dopamine, epinephrine, and isoproterenol?
Catecholamines
What is the defining feature of catecholamines?
They contain a benzene ring with hydroxyl groups and an amine group
What is the primary reason why catecholamines cannot be used orally?
They are quickly metabolized by enzymes in the gastrointestinal tract
What is the role of COMT in the metabolism of catecholamines?
It catalyzes the breakdown of catecholamines in the brain
Which property do all catecholamines have in common?
Quick metabolism by MAO and COMT enzymes
What distinguishes noncatacholamines from catecholamines?
They can be used orally
What is the main difference between direct and indirect adrenergic receptor activation?
Direct activation works on receptor binding, while indirect activation involves promotion of norepinephrine release
Why are noncatecholamines able to act in the central nervous system?
They are not affected by the blood-brain barrier
What is the distinguishing feature between dopamine and dobutamine among major catecholamines?
Dopamine contains a benzene ring with hydroxyl groups and an amine group, while dobutamine does not
Which enzyme is involved in the breakdown of catecholamines primarily within the liver?
Monoamine oxidase (MAO)
What effect does adrenaline have on adrenergic receptors?
It activates beta-adrenergic receptors in smooth muscle
Test your knowledge on adrenergic agonists, which exert effects by activating adrenergic receptors. Learn about the mechanisms of adrenergic receptor activation, including direct and indirect methods, and explore drugs like dopamine, epinephrine, isoproterenol, and ephedrine.
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