Pharmacology: Adrenergic Drugs and Catecholamines
24 Questions
2 Views

Choose a study mode

Play Quiz
Study Flashcards
Spaced Repetition
Chat to lesson

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What is the effect of α1 agonists on vascular smooth muscle?

  • No effect
  • Relaxation
  • Contraction (correct)
  • Vasodilation

    • What is the effect of β2 agonists on uterine muscle?

  • No effect
  • Relaxation (correct)
  • Contraction
  • Variable effect

    • What is the effect of β2 agonists on vascular smooth muscle?

  • Variable effect
  • Vasodilation (correct)
  • No effect
  • Vasoconstriction

    • What is the effect of β1 agonists on cardiac output?

    <p>Increase</p> Signup and view all the answers

    What is the use of epinephrine in cardiac arrest?

    <p>By intravenous and direct intracardiac injection</p> Signup and view all the answers

    What is the effect of β2 agonists on bronchial smooth muscle?

    <p>Bronchodilation</p> Signup and view all the answers

    What is the use of β2 agonists in obstetrics?

    <p>To delay premature labor</p> Signup and view all the answers

    What is the treatment of choice for anaphylactic shock?

    <p>Epinephrine</p> Signup and view all the answers

    What is the effect of catecholamines on the heart rate?

    <p>Increased heart rate</p> Signup and view all the answers

    Which type of smooth muscle contracts in response to α1 adrenoceptor stimulation?

    <p>All types of smooth muscle except that of the gastrointestinal tract</p> Signup and view all the answers

    What is the effect of β receptor stimulation on smooth muscle?

    <p>Relaxation</p> Signup and view all the answers

    Which receptors are located in the bladder trigone and sphincter area?

    <p>α1 receptors</p> Signup and view all the answers

    What is the effect of catecholamines on cardiac output?

    <p>Increased cardiac output</p> Signup and view all the answers

    What is the effect of β2 receptor stimulation on bronchial smooth muscle?

    <p>Relaxation</p> Signup and view all the answers

    Which receptors are involved in the contraction of prostatic smooth muscle?

    <p>α1 receptors</p> Signup and view all the answers

    What is the effect of β receptor stimulation on intracellular calcium concentration?

    <p>Decrease in intracellular calcium concentration</p> Signup and view all the answers

    What is the main effect of phenylephrine and oxymetazoline in the nose and sinuses?

    <p>Restricting the blood vessels in the nose and sinuses</p> Signup and view all the answers

    What is the purpose of adding adrenaline to local anesthetic solutions?

    <p>To delay the absorption of the local anesthetic drug</p> Signup and view all the answers

    How are circulating catecholamines usually inactivated?

    <p>By a combination of transporter uptake and metabolism by enzymes</p> Signup and view all the answers

    What is the main effect of amphetamines on the brain?

    <p>Increasing feelings of euphoria, energy and attention</p> Signup and view all the answers

    What is the main use of amphetamines in medicine?

    <p>Treating Attention Deficit Hyperactivity Disorder (ADHD)</p> Signup and view all the answers

    What is the effect of high doses of amphetamines on the user?

    <p>Marked anxiety or aggressiveness, paranoia, and, less commonly, seizures</p> Signup and view all the answers

    What is the effect of repeated dosing of amphetamines?

    <p>Rapid development of tolerance and dependence</p> Signup and view all the answers

    What is cocaine derived from?

    <p>The leaves of the coca plant</p> Signup and view all the answers

    Study Notes

    Catecholamines

    • Catecholamines are compounds containing a catechol moiety and an amine side chain.
    • They exert a powerful stimulant effect on the heart, increasing heart rate and force of contraction, resulting in a markedly increased cardiac output and cardiac oxygen consumption.

    Adrenergic Receptors

    • The heart is well supplied with β1 (predominant) and β2 receptors.
    • β1 receptors stimulate the heart, increasing heart rate and force of contraction.
    • β2 receptors cause relaxation of most kinds of smooth muscle.
    • α1 receptors stimulate contraction of smooth muscle.
    • α2 receptors are also present in vascular smooth muscle.

    Effects on Different Organs

    • Heart: Catecholamines increase cardiac output and cardiac oxygen consumption.
    • Smooth Muscle:
      • α1 receptors cause contraction of smooth muscle.
      • β2 receptors cause relaxation of smooth muscle.
      • Bronchial smooth muscle is strongly dilated by β2 agonists.
    • Vascular System:
      • α1 agonists contract vascular smooth muscle, increasing peripheral vascular resistance and venous pressure.
      • β2 agonists cause vasodilation, mainly endothelium-dependent and mediated by NO release.
    • Gastrointestinal Tract:
      • Both α and β receptors are present, leading to relaxation of smooth muscle.
      • Selective β2 agonists are used to treat asthma.
    • Genitourinary Tract:
      • α receptors mediate contraction of the bladder trigone and sphincter area.
      • β2 agonists cause relaxation of uterine smooth muscle.
    • Respiratory System:
      • β2 agonists, especially selective ones (e.g., salbutamol), are used to treat acute asthmatic bronchoconstriction.

    Clinical Applications

    • Cardiovascular Applications:
      • β1 agonists (e.g., dobutamine) may be useful in acute heart failure and shock.
      • Epinephrine has been used in cardiac arrest.
    • Genitourinary Tract:
      • β2 agonists (e.g., terbutaline) may be used to suppress premature labor.
    • Miscellaneous Indications:
      • Epinephrine is used to treat anaphylactic shock.
      • Phenylephrine and oxymetazoline (α agonists) are used to reduce nasal congestion.
      • Tetrahydrozoline is used to relieve redness in the eyes caused by minor eye irritations.

    Inactivation of Catecholamines

    • Circulating catecholamines are usually inactivated by a combination of transporter uptake and/or metabolism by several enzymes.

    Indirect-Acting Sympathomimetic

    • Amphetamines:
      • Are central nervous system stimulants.
      • Have a spectrum of stimulant effects, from alerting to euphoria and insomnia.
      • Used to treat attention deficit hyperactivity disorder (ADHD).
      • Inhibit presynaptic monoamine transporters, increasing dopamine, serotonin, and NA.
      • Can lead to marked anxiety, aggressiveness, paranoia, and seizures at high doses.
      • Rapidly develop tolerance and dependence with repeated dosing.
    • Cocaine:
      • Is a powerfully addictive stimulant drug.
      • Is made from the leaves of the coca plant native to South America.

    Studying That Suits You

    Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

    Quiz Team

    Description

    This quiz covers the classification of adrenergic drugs, their effects on different receptors, and the role of catecholamines in the heart. It also explores the clinical uses of adrenergic agonists.

    More Like This

    Use Quizgecko on...
    Browser
    Open
    Browser
    Browser