BASIC SCIENCE CONCEPTS

Question 1

Substrate/ligand?

Answer 1

compound that binds to a receptor and starts a chain reaction that produces an effect, such as altering a second messenger system

Question 2

Agonist?

Answer 2

drug that behaves in a similar manner to an endogenous (produced by the body) substrate.
Eg: Albuterol is a beta-2 agonist that behaves similarly to epinephrine. It binds to beta-2 receptors in the lungs, which activates several steps [e.g., increased cyclic adenine monophosphate (cAMP) production and decreased intracellular calcium] that result in bronchial smooth muscle relaxation.

Question 3

Antagonist?

Answer 3

drug that blocks an endogenous substrate from binding to its receptor (also called a blocker).
Eg: beta-1 blockers prevent adrenergic neurotransmitters (e.g., epinephrine) from binding to beta-1 receptors in the heart. Epi normally increases heart rate & contractility when it binds to beta 1 receptors. Blocking it causes decreased HR & contractility, thereby decreasing BP

Question 4

Enzymes?

Answer 4

Enzymes are compounds that speed up (catalyze) a reaction (e.g., creating a new compound or breaking down a compound into smaller parts).
Eg: theophylline blocks the phosphodiesterase (PDE) enzyme, which increases the second messenger cAMP, which in turn causes the smooth muscles of the bronchioles to relax

Question 5

Competitive inhibition

Answer 5

Competitive inhibition occurs when a drug binds to the same active site of a receptor or enzyme as the endogenous substrate, preventing the activity.
Eg: cyclic guanosine monophosphate (cGMP), which is involved in smooth muscle relaxation is degraded by the PDE-5 enzyme. Sildenafil a PDE-5 inhibitor, which binds at the same active site as cGMP and prevents the breakdown of cGMP.

Question 6

Non competitive inhibition

Answer 6

Drug binds to the enzyme or receptor at a site other than the active site & reduces the activity of the substrate

Question 7

Nervous system

Answer 7

Central nervous system & peripheral nervous system
CNS - Brain & spinal cord
PNS - nerves which connect CNS to rest of the body. Autonomic & somatic NS
Autonomic - involuntary (digestion, CO, BP). Presynaptic & post synaptic neurons.
Somatic - voluntary

Question 8

ANS

Answer 8

Sympathetic & parasympathetic NS
PSNS - rest & digest. muscarinic receptors. GI tract, bladder, eyes
SNS - fight or flight. epi or NE. smooth muscles, heart, lungs. alpha 1, beta 1 or beta 2 receptors. increase BP, HR & broncodilaton

Question 9

PSNS –SLUDD

Answer 9

Increase salivation, lacrimation, urination (bladder contraction), defecation/diarrhea, digestion.
Ach - nicotinic (Nn) - Ach- Muscarinic

Question 10

SNS

Answer 10

Increase HR, BP, pupil dilation, bronchodilation, glucose production
Decrease bladder contraction, saliva, peristalsis
Ach - nicotinic (Nn) - epi/NE (adrenergic receptors -a1, b1, b2

Question 11

1. Beta 2 agonist
2. beta 1 & beta 2 agonist
3. alfa 1 & beta 1 stimulator

Answer 11

1. terbutaline (acute, severe asthma exacerbation)
2. isoproterenol (used for bradycardia, but causes bronchodilation
3. epinephrine & NE vasopressors) increased vasoconstriction, HR and BP

Question 12

1. alfa 1, beta 1 & beta 2 blocker
2. beta 1 & beta 2 blockers
3. Centrally acting alfa 2 agonist

Answer 12

1. labetalol. used to increase vasodilation (which decreases BP) and decrease HR, but it can increase bronchoconstriction
2. propranolol & nadolol (non selective)
3. clonidine. alfa 2 adrenergic stimulation in brain leads to decreased sympathetic output. ie less Ach in Nn receptors, decreased release of epi/ne. less epi/ne binding to adrenergic receptors results in vasodilation, decreased BP, HR.

Question 13

Alpha 1 agonist & antagonist

Answer 13

Alpha 1 agonist - Inc vasoconstriction & BP (phenylephrine, dopamine dd)
Alpha 1 antagonist - smooth muscle relaxation Inc vasodilation, dec BP (doxazosin, carvedilol, phentolamine)

Question 14

Muscarinic agonist & antagonist

Answer 14

Musc agonist - Increase SLUDD (pilocarpine, bethanechol

Muc antagonist - dec SLUDD (atropine, oxybutynin)

Question 15

Beta 1 agonist & antagonist

Answer 15

Beta 1 agonist - Inc contractility, CO, HR (dobutamine, isoproterenol, dopamine dd
Beta 1 antagonist - Dec CO, HR (metoprolol & non selective beta blockers)

Question 16

Beta 2 agonist & antagonist

Answer 16

beta 2 agonist - inc bronchodilation (albuterol, terbutaline)
beta 2 antagonist - Inc bronchoconstriction (non selective beta blockers)

Question 17

MAO INHIBITORS

Answer 17

phenelzine
isocarboxazid
rasagiline
selegiline
methylene blue
liinezoliid

Question 18

role of mao
role of maoi in catecholamine induced hypertensive crisis
sx of hypertensive crisis

Answer 18

Tyrosine - dopa - dopamine
dopamine - NE by COMT & MAO
NE - Epi by MAO
epi - metabolites by MAO
Additionally tyramine is converted to its metabolites by MAO
MAOI inhibits conversion of dopamine to ne, ne to epi & epi to it metabolites leading to excess catecholamines. this plus other additive effects (bupropion, pseudoephedrine, levodopa) - leading to hypertensive crisis
SXs - hypertension, hyperthermia ,tachycardia, agitation, coma, death

Question 19

MAOI & serotonin syndrome

Sx of serotonin syndrome

Answer 19

tryptophan - serotonin - metabolites
serotonin to metabolites is by MAO
MAOI blocks the breakdown of serotonin
Inc serotonin + additive effects (SSRI, SNRI, tramadol, dextromethorphan) leading to Serotonin Syndrome
Sx-tremor, akathisia, clonus, hyperthermia, sweating