Basic Science Concepts Flashcards
What is a substrate (ligand)?
A substance that creates a signal or produces an effect by binding to a receptor, enzyme or transporter
What is the definition of endogenous?
A substance that is produced by the body (such as naturally-produced substrate)
What is the definition of exogenous?
A substance that is produced outside of the body (such as a drug or other chemical)
What is an agonist?
A substance that combines with a receptor to initiate a reaction. Can be endogenous or exogenous (mimicking an endogenous substrate)
What is an antagonist?
A substance that reduces or blocks a reaction. Can be endogenous or exogenous
What is the definition of induction?
When a substance increases the activity of an enzyme
What is the definition of inhibition?
When a substance decreases or blocks the activity of an enzyme
What does the central nervous system include?
The central nervous system (CNS) includes the brain and the spinal cord
What is the function of the CNS?
The CNS controls the functions of the rest of the body by sending signals to the peripheral nervous system (PNS)
What are the two main systems of the PNS?
Somatic and autonamic
What does the somatic nervous system control?
The somatic nervous system (voluntary) controls muscle movement
What does the autonomic nervous system control?
The autonomic (involuntary) controls other bodily functions, such as digestion, cardiac output and blood pressure
What are neurotransmitters?
The body’s chemical messenger
How is signal transmission in the CNS and PNS accomplished?
NTs are released from presynaptic neurons into the synaptic cleft, then they travel to postsynaptic neurons or other parts of the body to exert their effect
What are some examples of common NTs?
Acetylcholine (Ach), epinephrine (Epi), norepinephrine (NE), dopamine (DA) and serotonin (5-HT)
What is the primary NT involved in the somatic nervous system?
Ach
Describe the mechanism of action of ACh in the somatic nervous system.
It is released in response to neuron signals and binds to nicotinic receptors (Nn) in skeletal muscles to affect muscle movement
What are the two main divisions of the autonomic nervous system?
Parasympathetic and sympathetic
Describe the parasympathetic nervous system (PSNS) and how it works.
The PSNS is known as the “rest and digest” system. The PSNS works by releasing ACh, which binds to muscarinic receptors located throughout the body, including the GI tract, the bladder and the eyes. This results in a physiologic response known as SLUDD (salivation, lacrimation, urination, defecation and digestion)
Describe the sympathetic nervous system (SNS) and how it works.
The SNS is known as the “fight or flight” system. The SNS works by releasing Epi and NE, which act on adrenergic receptors (alpha-1, beta-1 and beta-2) in the CV and respiratory system. Activation of this system results in increased BP, HR and bronchodilation. Stimulation of beta-2 receptors in the GI tract increases glucose production to provide muscles with oxygen and energy. When the SNS is activate, functions like digestion and urination are minimized to focus on the more important bodily functions for “fight or flight”
What is the mechanism by which cells communicate and send signals?
The substrate binds to receptors on the receiving cell to cause a signal or change. Substrates can be endogenous or exogenous. Once bound, the receptor substrate complex causes some change that results in a biological effect (e.g. secretion of hormone, contraction of muscle)
What is competitive inhibition?
Competitive inhibition occurs when an antagonist binds to the same active site of a receptor as the endogenous substrate, preventing the activity
What is non-competitive inhibition?
In non-competitive inhibition, the antagonist binds to the receptor at a site other than the active site (called the allosteric site) which changes the shape of the active site and prevents the endogenous substrate from binding
What is an example of a beta-2 agonist?
Albuterol
What is the MOA of albuterol?
Albuterol, a beta-2 agonist that behaves similarly to epinephrine. It binds to beta-2 receptors in the lungs, which activate several steps and results in bronchial smooth muscle relaxation
What is the MOA of beta-1 blockers?
Beta-1 blockers prevent adrenergic neurotransmitters from binding to beta-1 receptors in the heart. By blocking the receptor, beta-1 blockers decrease heart rate and contractility
What is the endogenous substrate for the muscarinic receptor?
Acetylcholine
What are some examples of drug agonists of muscarinic receptors and what is the agonist action?
Pilocarpine and betanechol increases SLUDD
What are some examples of drug antagonists of muscarinic receptors and what is the antagonist action?
Atropine, oxybutynin decreases SLUDD
What is the endogenous substrate of nicotinic receptors?
Acetylcholine
What is an example of a drug agonist of nicotinic receptors and what is the agonist action?
Nicotine increases HR, BP
What is an example of a drug antagonist of nicotinic receptors and what is the antagonist action?
Neuromuscular blockers (e.g. rocuronium) causes neuromuscular blockade
What are the endogenous substrates of alpha-1 (mainly peripheral), alpha-2 (mainly brain; central) and beta-1 receptors?
Epinephrine and norepinephrine
What are examples of drug agonists of alpha-1 receptors and what is the agonist action?
Phenylephrine, dopamine (dose-dependent) causes smooth muscle contraction and increased BP
What are examples of drug antagonists of alpha-1 receptors and what is the antagonist action?
Alpha-1 blockers (doxazosin, carvedilol, phentolamine) cause smooth muscle vasodilation and decrease BP
What are examples of drug agonists of alpha-2 receptors and what is the agonist action?
Clonidine, brimonidine (ophthalmic, for glaucoma) decreases teh release of epinephrine and norepinephrine and decreases BP and HR
What are examples of drug antagonists of alpha-2 receptors and what is the antagonist action?
Ergot alkaloids, yohimbine increases BP, HR
Wha are examples of drug agonists of beta-1 receptors and what is the agonist action?
Dobutamine, isoproterenol, dopamine (dose-dependent) increases myocardial contractility, CO, HR
What are examples of drug antagonists of beta-1 receptors and what is the antagonist action?
Beta-1 selective blockers (e.g. metoprolol) and non-selective beta-blockers (e.g. propranolol and carvedilol) decreases CO, HR
What is the endogenous substrate of beta-2 receptors?
Epinephrine
What are examples of drug agonists of beta-2 receptors and what is the agonist action?
Albuterol, terbutaline, isoproterenol causes bronchodilation
What are examples of drug antagonists of beta-2 receptors and what is the antagonist action?
Non-selective beta-blockers (e.g. propranolol, carvedilol) causes bronchoconstriction
What is the endogenous substrate of dopamine receptors?
Dopamine
What are examples of drug agonists of dopamine receptors and what is the agonist action?
Levodopa and pramipexole causes many renal, cardiac and CNS effects
What are examples of drug antagonists of dopamine receptors and what is the antagonist action?
First generation antipsychotics (e.g. haloperidol) and metoclopramide cause many renal, cardiac and CNS effects
What is the endogenous substrate for serotonin receptors?
Serotonin
What are examples of drug agonists of serotonin receptors and what is the agonist action?
Triptans causes many platelet, GI and psychiatric effects
What are examples of drug antagonists of serotonin receptors and what is the antagonist action?
Ondansetron, second-generation antipsychotics causes many platelet, GI and psychiatric effects
What are enzymes?
Enzymes are compounds that speed up (catalyze) a reaction
What are some examples of common enzymes?
Acetylcholinesterase, ACE, COMT, COX, MAO, PDE, Vitamin K epoxide reductase, Xanthine oxidase
What is the endogenous effects of acetylcholinesterase?
Breaks down acetylcholine
What are some drugs that target acetylcholinesterase and what is its drug actions?
Acetylcholinesterase inhibitors: donepezil. rivastigmine, galantamine
- MOA: bloc acetylcholinesterase resulting in increased ACh levels (used to treat Alzheimer’s disease)
What is the endogenous effects of angiotensin-converting enzyme (ACE)?
Converts angiotensin I to angiotensin II (a potent vasoconstrictor)
What are some drug examples that target ACE and what is the drug action?
ACE inhibitors (e.g. lisinopril, ramipril) - Inhibit production of angiotensin II, resulting in decreased vasoconstriction and decreased aldosterone secretion; used to treat hypertension, heart failure and kidney disease
What is the endogenous effect of catechol-o-methyltransferase (COMT)?
Breaks down levodopa
What are some drug examples that target COMT and what is the drug action?
COMT inhibitors: entacapone
- MOA: blocks COMT enzyme to prevent peripheral breakdown of levodopa, resulting in increase duration of levodopa (used to treat Parkinson disease)
What is the endogenous effects of cyclooxygenase?
Converts arachidonic acid to prostaglandins (cause inflammation) and thromboxane A2 (causes platelet aggregation)
What is a drug example that targets COX and what is the drug action?
NSAIDS (e.g. aspirin, ibuprofen)
- MOA: Block COX enzymes to decrease prostaglandins and thromboxane A2 (used to treat pain/inflammation and decrease platelet aggregation [aspirin])
What is the endogenous effect of monoamine oxidase (MAO)?
Breaks down catecholamines (e.g. DA, NE, Epi, 5-HT)
What are drug examples that target MAO and what is its drug action?
MAO inhibitors: phenelzine, tranylcypromine, isocarboxazid, selegiline, rasagiline, methylene blue, linezolid
- MOA: block MAO which increases catecholamine levels (used to treat depression)
*If catecholamines increase too much, toxic effects can occur, (e..g hypertensive crisis or serotonin syndrome)
What is the endogenous effect of phosphodiesterase (PDE)?
Breaks down cyclic guanosine monophosphate (cGMP), a smooth muscle relaxant
What’s a drug example that targets PDE and what’s the drug action?
PDE-5 inhibitors (e.g. sildenafil, tadalafil)
- MOA: competitively bind to the same active site as cGMP on the PDE-5 enzyme, preventing the breakdown of cGMP and prolonging smooth muscle relaxation (used to treat erectile dysfunction)
What is the endogenous effect of Vitamin K epoxide reductase?
Converts vitamin K to the active form required for production of select clotting factors
What is a drug example that targets vitamin K epoxide reductase and what is the drug action?
Warfarin
- MOA: blocks vitamin K epoxide reductase enzyme which decreases production of clotting factors II, VII, IX, and X (used to treat or prevent blood clots)
What is the endogenous effect of xanthine oxidase?
Breaks down hypoxanthine and xanthine into uric acid
What is a drug example that targets xanthine oxidase and what is its drug action?
Xanthine oxidase inhibitor: allopurinol
- Blocks xanthine oxidase enzyme which decreases uric acid production (used to prevent gout attacks)
Describe the structure of Amoxicillin.
Beta-lactam, penicillin antibiotic that contains a beta-lactam ring fused to a 5-sided ring
*Hypersensitivity: cross-reactive to other drugs with beta-lactam ring
Describe the structure of Ceftriaxone.
Beta-lactam, cephalosporin antibiotic that contains a beta-lactam ring fused to a 6-sided ring
*Hypersensitivity: cross-reactive to other drugs with beta-lactam ring
Describe the structure of ertapenem.
Beta-lactam, carbapenem antibiotic that contains a beta-lactam ring fused to a 5-sided ring
*Hypersensitivity: cross-reactive to other drugs with beta-lactam ring
Describe the structure of Aztreonam.
Monobactam antibiotic that contains a lactam ring not fused to another ring
*Hypersensitivity: not cross-reactive with beta-lactam antibiotics
Describe the structure of Gentamicin.
Aminoglycoside antibiotic that contains an amino group and a glycoside group
Describe the structure of slufamethoxazole
Sulfonamide antibiotic that contains a sulfonamide group
*Hypersensitivity: cross-reactive to other drugs containing a sulfonamide
Describe the structure of aspirin
Salicylate non-steroidal anti-inflammatory analgesic that contains an acidic, carboxyl group
Describe the structure of ibuprofen
Non-steroidal anti-inflammatory analgesic that contains a carboxyl group
Describe the structure of Amphetamine
Stimulant that contains a primary amine functional group
Describe the structure of Levothyroxine
Thyroid hormone (T4) that contains four iodine molecules in the structure converted to T3 (triiodothyronine) in the body
Describe the structure of Amiodarone
Class III antiarrhythmic that contains two iodine molecules in the structure
*Explains the hyper- and hypothyroid effects and contraindication in patients with an iodine allergy
Describe the structure of Fenofibrate
Fibrate, for high cholesterol, contains ketone groups
Describe the structure of Amitriptyline
Tricyclic antidepressant that contains three rings in the structure
Describe the structure of Chlorpromazine
Phenothiazine antipsychotic that contains a thioether group
