Lecture 3 Flashcards
Ligand
Molecules that bind to receptors
What is a protein that participates in intracellular communication via chemical signals?
Receptor
What are the 4 major classes of receptors?
Ligand-gated Ion channels
Protein Receptors
G-Protein Coupled receptors
Ligand-activated transcription factors
Nictonic Ach, glutamate, Glycine and GABA(a) all use what type of receptor?
Ligand-gated ion channels
Growth factors, insulin, and peptide hormones use which kind of receptor?
Protein receptor
Muscarinic receptor, alpha and beta adrenergic receptor proteins, and eicosamoids use what type of receptor?
G-Protein coupled receptors
steroid hormones, thyroid hormone, vit D use what kind of receptor?
Ligand-activated transcription factors
activating the alpha1-adrenergic receptor lead to what?
Activation of phospholipase
activating the alpha2- adrenergic receptor leads to what?
Inhibition of adenylyl cyclase
activating the B-adrenergic receptor leads to what?
Stimulation of adenylyl cyclase
Activation of muscarinic receptor leads to what?
Activation of phospholipase
What are the two general classes of ion channels?
Voltage-gated
Ligand-gated
What type of ion channel is activated by alterations in membrane voltage? (Na+ channel)
Voltage-gated ion channel
Some ion channels are able to become _________ and in this state the channels permeability can’t be altered for a certain period of time.
Refractory or inactivated
What type ion channel if activated after binding specific ligands or drugs?
Ligand-gated
What two drug classes act by altering the conductance of ion channels?
Local anesthetics (voltage) Benzodiazepines (ligand)
How is cAMP produced?
Activation of adenyly cyclase by alpha-GTP subunits
What are two benefits of a signal-transduction pathway (second messenger)?
Signal amplification
Signal specificity
What is an example of a protein-linked kinase receptor?
Tyrosine kinase (has insulin receptors)
What receptor requires a signal to pass through the plasma membrane?
Intracellular receptors
What are important drug receptors located outside the plasma membrane?
Extracellular receptors
What are 2 drugs that have strong chemical bonds (covalent) that are irreversible?
Chemo
Aspirin (for the life of the platelet ~7 days)
Spare receptors are common for those that bind what?
Hormones and neurotransmitters
All these terms refer to what: Desensitization, tachyphylaxis, refractoriness, resistance, tolerance
?
Effect of a drug often diminishes when given continuously or repeatedly
Loss of receptor function leads to what?
Rapid desensitization due to change in receptor conformation
Reduction of receptor number leads to what?
Long-term desensitization due to change in receptor number
What are 2 ways drug desensitization can happen that aren’t receptor mediated?
- Reduction of receptor coupled signaling components
2. Increased metabolic degradation
what are some advantages of sublingual route of administration?
Rapid response
No 1st pass effect
bypass GI acids
What is the reduction or ameiloration of drug effects due to opposing homeostatic response?
Physiological adaptation
What is the probability of a drug occupying a receptor at any given instance?
Affinity
What is the way the body handles the drug through absorption, distribution, biotransformation, and elimination?
Pharmacokinetics
What is the process by which a drug leaves its site of administration and reaches the blood stream.
absorption
What is the process by which the drug leaves the blood stream and enters the interstitial and/or cellular fluids
Distribution
The alteration of the chemical structure of a drug by an enzyme
metabolism
Most drugs move _____ across a membrane.
Passively
Most diffusion occurs _____ cells, not between them.
through
The greater the fraction of the drug that is ________, the greater the rate of diffusion.
Nonionized (uncharged)
Non-ionized drugs diffuse easily at a ____ pH
High
An intrathecal injection goes where?
Spinal fluid
IP injection goes where?
Intraperitineal (into intestines)
What is the max volume for an IM injection?
3 mL (in buttocks)
WHat is the max for a subQ injection?
1 mL
What type of administration should be used on an unconscious patient?
Rectal
What is first pass metabolism?
Where the drug goes through portal circulation. Can inactivate a drug
Which has a faster absorption- IM or SubQ?
IM
What type of parenteral administration has the greatest risk of infection?
IV
ligands include:
drugs, signaling molecules, hormones, neurotransmitters
If a drug binds to a receptor but doesn’t produce a response it is referred to as what?
antagonist
Time for ligand-gated ion channels?
hours to occur
Time for protein receptors?
seconds to minutes
Time for G-protein Coupled Receptors?
seconds to minutes
Time for ligand-activated transcription factors?
milliseconds! (fastest)
Examples of intracellular receptors (4)
nitric oxide, steroid, thyroid hormone, vitamin D
most drug-receptor interactions are?
reversible and weak chemical bonds
What binds reversibly to active site and blocks agonist?
Competitive Antagonist
What binds irreversibly and prevents conformational change required for the activation of receptors?
Noncompetitive Antagonist
What is an example that increases metabolic degradation?
Barbiturates - induce P450 enzymes that degrade drug
Efficacy
magnitude of effect that can be produced by a drug
