Drugs and Receptors Flashcards
What is pharmacokinetics?
What the biological system does to the drug
Absorption, Distribution, Biotransformation and excretion
What is pharmacodynamics?
What the drug does to the biological system
Mechanisms of action and effects of drugs
What is intrinsic activity?
Inherent property of the drug to impart a cellular response
Agonists have intrinsic activity
Antagonists have no intrinsic activity
What is an inverse agonist?
Agents which stabilize the receptor in its inactive conformation
(Constituitively active receptors)
How are receptors classified?
Based on effects and potencies of selective agonists/antagonists and molecular biology
What is drug specificity?
Ability to bind or act on a particular cell type or tissue
What is drug selectivity?
Ability of a drug to exert a single effect
Depends on specificity/receptor distribution
What are three types of enzymatic receptors?
Protein kinases
Protein Kinase-associated receptors
Guanylyl Cyclase
What is the largest family of physiological receptors?
G-protein-coupled receptors
Multiple G-protein types that have different effects
What is the function of cAMP?
Regulates the activity of PKA
Inactivated by PDE
What is the function of cGMP?
Regulates the activity of cGMP-dependent protein kinase (PKG)
What is desensitization?
Continuous stimulation of the receptor results in downregulation of the receptor
Receptor gets recycled or degraded
Long-term administration of an agonist
What is supersensitization?
Chronic administration of an antagonist
Causes decreased downregulation and when the antagonist is removed, produces an exaggerated response
What is tachyphylaxis?
loss of response on repeated administration
What are some drug actions that are not receptor-mediated?
Antacids
Osmotic diuretics
Cholesterol-binding resins
Antibiotics (no human receptors activated)
