Chapter 2: Basic Science Concepts Flashcards
Definition: substrate (ligand)
a substance that creates a signal or produces an effect by binding to a receptor, enzyme or transporter
Definition: endogenous
a substance that is produced by the body
Definition: exogenous
a substance that is produced outside of the body
Definition: agonist
a substance that combines with a receptor to initiate a reaction
can be endogenous or exogenous
Definition: antagonist
a substance that reduces or blocks a reaction
can be exogenous or endogenous
Definition: induction
when a substance iincreases the activity of an ezyme
Definition: inhibition
when a substnace decreases or blockss the activiity of an enzyme
central nervous system
- includes brain and spinal cord
- controls rest of body by sending signals to peripheral nervous system
2 main systmes of the peripheral nervous system
- somatic: voluntary movememnt
- autonomic: involuntary body functions (digestion, CO, BP)
neurotransmitters
- body’s chemical messengers
- released from presynaptic neurons into synaptic cleft to be picked up by post synaptic neurons
common neurotransmitters (5)
- acetylcholine (ACh)
- epinephrine (epi)
- norepinephrine (NE)
- dopamine (DA)
- serotonin (5HT)
primary neurotransimitter involved in somatic NS
ACh: it binds to nicotinic receptors (Nn) in skeletal muscles
main divisions of autonomic nervous system
- parasympathetic: “rest and digest”, releases ACh which binds to muscarinic receptors → SLUDD (Salivation, Lacrimation, Urination, Defecation, Digestion)
- sympathetic: “fight or flight”, releases epi and NE which act on adrenergic receptors → increased BP, HR, bronchodilation (+ opposite of SLUDD)
Adrenergc receptors
- alpha1
- beta1
- beta2
Definition: competitive inhibition
when an antagonnist binds to the same active site of a receptor as the endogenous substrate → prevent endogeous from binding
Definition: non-competitive inhibition
when the antagonist binds to the receptor a t asite other than the activve site (allosteric site) → changes shape of active site and prevent endogenous substrate from binding
ACh receptor(s)
- muscarniic
- nicotonic
Epi receptor(s)
- alpha 1 (peripheral action)
- alpha 2 (CNS action)
- beta 1 (heart)
- beta 2 (lungs)
NE receptor(s)
- alpha 1 (peripheral action)
- alpha 2 (CNS action)
- beta 1 (heart)
DA receptor(s)
dopamine
5HT receptor(s)
5HT
muscarinic receptor
- agonist action
- drug agonists
increase in SLUDD
- salivation
- lacrimation
- urination
- defecation
- digestion
- pilocarpine
- bethanechol
muscarinic receptor
- antagonist action
- drug antagonists
decrease in SLUDD
- salivation
- lacrimation
- urination
- defecation
- digestion
- atropine
- oxybutinin
nicotonic receptor
- agonist action
- drug agnoists
increase HR and BP
nicotine
nicotinic receptor
- antagonist action
- drug antagonsits
neuromuscular blockade
NMBs (rocuronium)
alpha 1 receptor
- agonist action
- drug agonists
- smooth muscle vasoconstirction
- increased BP
- phenylephrine
- dopamine (dose dependent)
alpha 1 receptor
- antagonist action
- drug antags
- smooth muscle vasodlation
- decreased BP
alpha 1 blockers (doxazosin, carvedilol, phentolamine)
alpha 2 receptor
- agonist action
- drug agonists
- decreased release of epi and NE
- decreased BP and HR
- clonidine
- brimonidine
beta 1 receptor
- agonist action
- drug agonists
- increased myocardial contractility
- increased CO and HR
- dobutamine
- isoproterneol
- dopamine (dose dependent)
alpha 2 receptor
- antag actions
- drug antags
increased BP and HR
- ergot alkaloids
- yohimbine
beta 1 receptor
- antag actions
- drug antags
decreased CO and HR
- beta 1 selective blockers (metoprolol)
- beta 1 non-selective blockers (propranolol, carvedilol)
beta 2 receptor
- agoist action
- drug agonist
bronchodilation
- albuterol
- terbutaline
- isoproterenol
beta 2 receptor
- antag actions
- drug antags
bronchoconstriction
nonselective beta blockers: propranolol, carvedilol
dopamine receptor
- agonist actions
- drug agonists
renal, cardiac, and CNS effects
- levodopa
- pramipexole
dopamine receptor
- antag actions
- drug antags
renal, CNS, cardiac effects
- many first gen antipsychotics (haloperidol)
- metoclopramide
serotonin receptor
- agonsit action
- durg agonists
platelet, GI, and psych effects
triptans (sumatriptan)
serotonin receptor
- antag actions
- drug antags
platelet, GI and psych effects
- ondansetron
- second gen antipsychotics (quetiapine)
Definition: enzyme
compound that speeds up (catalyzes) a reactoin
acetylcholinesterase endogenous effect
break down ACh
drugs that target acetylcholinesterase (and their action)
acetylcholinesterase inhibitors: donepezil, rivastigmine, galantamine
block acetylcholinesterase → increased ACh levels
drugs that target angiotensin converting enzyme (and their action)
ACE inhibitors: lisinopril, ramipril
inhibit production of angiotensin II → decreased vasoconstriction and decreased aldosterone secretion
angiotensin converting enzyme endogenous effects
convert angiotensin I to II
Catechol-O-mathyltransferase endogenous effects
breaks down levodopa
cyclooxygenase endogenous effects
convert arachidonic acid to
- prostaglandins (inflammmation)
- thromboxane A2 (plt aggregation)
monoamine oxidase endogenous effects
break down catecholamines (DA, NE, epi, 5-HT)
phosphodiesterase endogenous effects
break down cyclic guanosine monophosphate (cGMP)
vitamin K epoxide reductase endogenous effects
convert vitK to active form (required for production of selective clotting factors)
xanthine oxidase endgoenous effects
break down hypoxanthine into xanthine and then xanthine into uric acid
drugs that target catechol-O-methyltransferase (and their action)
COMT inhibitor: entacapone
break down COMT enzyme → prevent peripheral breakdown of levodopa → increase duration of action of levodopa
drugs that target cyclooxygenase (and their action)
NSAIDs (asa, ibuprofen)
block COX enzymes → decrease prostaglandins and thromboxane A 2
drugs that target monoamine oxidase (and their action0
MAOi:
- phenelzine
- isocarboxazid
- tranylcypromine
- selegiline
- rasagiline
block MAO → increase catecholamine levels (too high though and you get HTN crisis or serotonin syndrome)
drugs that target phosphodisterase (and their action)
PDE-5 inhibitors: sildenafil, tadalafil
comeptitively bind to same active site as cGMP on PDE-5 → prevent breakdown of cGMP → prolong smooth muscle relxation
drugs that target vitamin K epoxide reductase (and their action)
warfarin
block vitK epoxide reductase ezyme → reduce production of clotting factors II, VII, IX, and X
drugs that target xanthine oxidase (and their action)
xanthine oxidase inhibitor: allopurinol
block xanthine oxidase enzyme → decrease uric acid production
how may a MAOI contribute to hypertesnive crisis
- MAOI: block breakdown of epi and NE
- addition of other drugs/foods that increase catecholamines can lead to excess → HTN crisis
HTN crisis: HTN, tachycardia, agitation, death
how may a MAOI contribute to serotonin syndrome
- MAOI: block breakdwon of 5-HT
- additiion of other durgs that increase 5-HT can lead to serotonin syndrome
serotonin syndrome s/s
- tremor
- akathisia
- clonus
- hyperthermia, sweating
Definition: stability
extent to whcih a product retains, within specified liits, and throught its period of storage and use, the same properites and characteristics it possessed at the time it was made
reactions that cause drug degradation
- oxidation-reduction
- hydrolysis
- photolysis
Definition: oxidation and reduction
oxidation: compound loses electrons
- catalyzed by heat, light, and metal ions
- produces free radicals → can lead to oxidation chain reaction
reduction: compound gains electrons
Definition: re-dox reaction
when one compound is oxidized and another reduced in the same reaction
drugs that are most likely to oxidize contain what molecular structure
hydroxyl group directly bound to an aromatic ring
epinephrine, phenylephrine
how to protect drug from oxidation
- light protection: amber glass
- temperature control
- antioxidants (inhibit free radicals): VitC and vit E
- chelating agetns (binds to catalyst → prevent reaction): common chelators have the letters ED
- pH control: buffer
Definition: hydrolysis
when water causes cleavage of a bond in a molecule
functional groups most susceptible to hydrolysis
- esters
- amides
- lactams
how to protect a drug from hydrolysis
protect form moisture
- adsorbents (dessicants): absorb moisture that enters container
- lyophilized powders: store drug as powder and reconstitute when dispensing to reduce risk of hydrolysis
- hygroscopic salt (water absorbing salt): use salt form of a drug that is less hygroscopic
- light protection
- chelating agents
- temp control
- pH control
Definition: photolysis
breakage of covalent bonds due to UV light expsure
