Pharmacodynamics Flashcards
Drug
Any substance that when administered to a living organisms produces a biological affect
Pharmacology
Study of how function of living systems is affected by chemical agents
Pharmacokinetics
Study of absorption, distribution, metabolism, and a excretion of drug
Pharmacodynamics
Study of effects of drugs and their mechanisms of action
Toxicology
Study of adverse effects of drugs.
Drug receptor
Component of organism with which the drug interacts. Sometimes called drug target.
What types of ion channels can drugs act upon?
Voltage gate and ligand gated
For ligand gated channels, what is an example of ligands?
Neurotransmitters (acetylcholine) or an intracellular mediator (cAMP and second messengers)
What two drugs classes act by altering the conductance of ion channels?
Local anesthetic and benzodiazepines
How do local anesthetics work?
Block voltage gated sodium channels in neurons that transmit pain information from the periphery to the CNS. this prevents action potential propagation and pain perception.
How do benzodiazepines work?
Bind to the GABAa receptor in neuronal membranes in the CNS. GABAa functions as a chloride ion channel and is activated by GABA (inhibitory neurotransmitter). This enhances the ability of GABA to open the chloride channel, hyperpolarizing the neuron.
On which receptor do most prescription drugs act?
G protein linked receptors
Albuterol
Beta-2 agonist use for asthma
Propranolol
A beta antagonist used for hypertension
Bethanechol
Muscarinic (acetylcholine receptor) agonist used for atonic bladder
Ipratropium
Muscarinic antagonist used for asthma
what are the three components of G protein linked receptors?
Cell surface receptor, G protein, effector (enzyme or an ion channel)
G protein effectors
G proteins can either directly control ion channels or they can interact with enzymes which leads to the production of second messengers
What are the most frequent target enzymes for G proteins?
Adenylyl cyclase and phospholipase C
What was Gs do?
Increase adenylyl cyclase
What does Gi do?
Decrease adenylyl cyclase and open potassium channels by decreasing cAMP
What does Gq do?
Increases the amount of phospholipase C
What does IP3 do?
releases calcium from the ER, which allows calcium to control many enzymes
What are some calcium meditated responses?
Smooth muscle contraction, increased force of contraction of cardiac muscle, secretion from exocrine glands, neurotransmitter release, hormone release
What are the ligand regulated transmembrane enzymes?
Tyrosine kinase, serine/threonine kinase, and guanylyl cyclase
What are the receptors for tyrosine kinase?
Insulin receptor, epidermal growth factor receptor, platelet derived growth factor, and nerve growth factor receptor
What can gain of function mutations in tyrosine kinase receptors cause?
Cancer, because tyrosine kinase receptors play an important role in cellular growth and differentiation
Imatinib
Tyrosine kinase inhibitor that is effective for leukemia
Cytokine Receptors
Respond to peptide ligand like growth hormone, prolactin, erythropoietin, and interferons. Have no intrinsic enzymatic activity. Bind to an intracellular tyrosine kinase from the Janus-kinase (JAK) family.
What usually makes up intracellular receptors?
Nuclear receptors, enzymes, structural proteins