Chapter 7 (drugs that affect the autonomic NS) Flashcards
almost all drugs effect some aspect of our…
nervous system
PNS subdivisions
somatic NS and ANS
ANS
autonomic nervous system
ANS subdivisions
sympathetic and parasympathetic
somatic NS
those for which we have conscious control (like skeletal muscle movements)
ANS
those functions we do not control consciously like HR, BP, saliva secretion, gastric acid secretion, peristalsis, etc.
almost every organ has innervation from both…
parasympa and sympa NS; they work in concert and in opposition
They exist in homeostatic balance between each other
sympa fight or flight balanced by…
parasympa rest and digest
NE
norepinepherine
Ach
acetylcholine
NE used at…
adrenergic receptors for sympa NS
Ach used at…
cholinergic receptors for parasympa NS
agonists
bind to rc THEN cause a positive action in the cell
antagonists
bind to rc but do not cause a positive action
parasympathomimetic
parasympathetic agonist
parasympatholytic
parasympathetic antagonist
sympathomimetic
sympathetic agonist
sympatholytic
sympathetic antagonist
cholinergic drugs
act as agnoists to Ach rc and bind to Ach rc to cause a positive effect
cholinergic antagonists
bind to Ach rc but have anticholinergic effects (often side effects of preventing parasympa action like dry mouth or constipation)
adrenergic named from
adrenaline (epi in England)
adrenergic receptors
alpha (1 and 2) and beta (1, 2, and 3)
cholinergic receptors
muscarinic and nicotinic
nicotinic receptors
found at the NMJ to cause somatic muscle contraction
muscarine
named from mushroom it was isolated from (amantina muscaria)
parasympa vs. sympa balance
balanced under normal conditions, but disease states shift the balance off (like high BP, dysrhythmia, irritable bowl, etc.) so drugs are needed to maintain balance
endogenous
those that are part of the natural physiology of our body
bethanechol
muscarinic agonist; not a great drug b/c of side effects but does increase bowl speed and increase bladder drainage for those with urinary/bowl retention
*unlike Ach, has a long duration of action
One of few cholinergic agonists that isn’t a nerve gas
atonic bladder/bowl
no tone, so pt. can’t pee or poop
patients at risk for bladder/bowl atonicity
women with past births, someone with spinal cord injury, or someone on drug causing bladder retention
there are no good drugs for the parasympa NS b/c…
side effects are very bad b/c systemic inhibition or activation of parasympa NS is sucky
best cholinergic agonists
nerve gas poisons like Serin gas b/c they are very potent and harmful
atropine
antidote to Ach, bethanechol, and Sarin gas b/c it inhibits parasympa effects
It is a parasympatholytic
Prototype parasympatholytics
scopolamine
from nightshade; it is very similar to atropine as a parasympatholytic. Used originally to dilate pupils by blocking parasympa action of constricting them.
how do eye surgeons dilate pupils?
use eye drops that are anticholinergic and are sympathetic agonists
spasm
opposite of atony
bladder/bowl spasm
overactive
anticholinergic drugs
used to block over-activity of GI and urinary tracts
Ditropan
oxybutynin; muscarinic antagnoist
antispasmodic to relax smooth muscle, often given in combo with sedatives and anti-infectives (side effects suck b/c of dry mouth, constipation, HR effects, breathing effects, etc.)
B/c of side effects, really only good when used locally
*developed specifically for muscarinic bladder antagonism but doesn’t work so well
DA
dopamine
emergency situations needing adrenergic agonists
epi is used in emergency, then dopamine or dobutamine is used to stabilize the pt. to support CV system
dopamine
ephedrine like drug with B and A agonist action
dobutamine
ephedrine like drug with B and A agonist action
Inderal
propranolol; non-selective B blocker (first one created)
New B blockers are more specific to certain receptors.
B2 receptor
found in lungs; never want antag binding b/c never a good idea to constrict bronchal tube. Ags dilate pulomnary tube.
B1 receptor
specific B1 receptors are found on heart; ags increase HR
a1 receptor
found in BVs; ags constrict BVs to increase BP
curare
amazonian dart poison, blocks nicotinic receptor so paralysis occurs b/c somatic NS does not work (no NMJ action so muscles cannot contract); a true muscle relaxant!
A neuromuscular blockade occurs
epinepherine; norepinepherine
prototype adrenergic receptor agonists
Bind to all alpha and B1 and B2 receptors to…
Raise BP and HR, dilate lungs and pupils, increase blood flow to muscles and brain
albuterol
mostly B2 agonist used in inhalers to treat asthma
Very little effect on heart rate
DA
dopamine
dopamine; dobutamine
two catecholamine adrenergic receptor agonists
catecholamines
many sympathetic agonists are this type of molecule; like epi, NE, and DA
have 1,2 dihyroxy benzene structure (catechol structure)
5 non-catecholamine adrenergic receptor agonists
cocaine, ephedrine, pseudoephedrine, phenylephrine,
and ampthetamine are non-catecholamine adrenergic rc agonists
Inderal
propranolol; B blocker (sympatholytic). Also an analgesic.
acetylcholine
cholingergic (muscarinic and nicotinic) agonist
Lowers BP and HR, constricts lungs and pupils, increase blood flow to digestive tract and kidneys, and activates salivation
antihistamines (such as diphenhydramine)
muscarinic antagonist
as side effects, many antihistamines, antipsychotics, antidepressants, and antiparkinsons drugs cause dry mouth and constipation
NE is main NT of…
sympa NS
anticholinergic drugs addiction
not addictive b/c side effects are so sucky like constipation, urinary retention, dry mouth, etc.
Lomotil
atropine / diphenoxylate; an opioid used to treat diarrhea that makers put atropine in so its not abused; will cause bad side effects so nobody will abuse
Demerol
meperidine; mu receptor agonist
all NS subdivisions carry…
sensory info, in addition to their efferent neuron effects
enteric NS
recieves sensory info and causes smooth muscle movement and acid secretion for GI tract
