Learn: Pharm- ANS (1/2)

Sympathetic origin of fibers

thoraco-lumbar spinal cord

Sympathetic length of fibers

short preganglionic and long postganglionic

Sympathetic location of ganglia

close to spinal cord

Parasympathetic origin of fibers

brain and sacral spinal cord

Parasympathetic length of fibers

long preganglionic and short postganglionic

Parasympathetic location of ganglia

in visceral organs

Sympathetic output is diffuse because post ganglionic neurons may innervate ___________

more than one organ

(triggering a all or nothing effect --> fight or flight)

Parasympathetic output is discrete because post ganglionic neurons are not branched out but _____

directed to a specific organ

(allowing for organs to be activated separately like a dimmer light)

Parasympathetic actions on the body include

(think "rain forest")

-stimulation of tears

-copious, watery saliva

-decreased HR

-increased muscle motility and tone

-stimulation of erection

-relaxation of trigone

-increased secretions in bronchioles

-near vision (ciliary muscle)

Sympathetic actions on the body include

(think "dry desert")

-thick, viscous saliva

-increased HR

-decreased muscle motility and tone

-relaxation of uterus

-blood vessels constrict

-stimulation of ejaculation

-contraction of trigone

-epi and norepi

-dilation of trachea

-dilated pupils

Which of the following is not a parasympathetic agonist?

parasympatholytic

Acetylcholine is the neurotransmitter that mediates contraction of skeletal muscles. Which of the following autonomic receptor types does acetylcholine bind to on the skeletal muscle cell to mediate muscle contraction?

Nicotinic

Which of the following physiologic changes occurs when the parasympathetic nervous system is activated?

Increase in gastric motility

Which physiologic change is expected when the sympathetic nervous system is inhibited using a pharmacologic agent?

Reduction in heart rate

Which of the following is correct regarding activation of receptors on the effector organs in the ANS?

Acetylcholine activates muscarinic receptors.

types of cholinergic agonists:

direct acting

indirect acting

direct acting cholinergic agonist

bind to the muscarinic or nicotinic receptors

indirect acting cholinergic agonist

block acetylcholinesterase

the use of ________ acting cholinergic agonists can lead to a cholinergic crisis

indirect

(sx: paralysis, convulsions)

Neurotransmission in cholinergic neurons includes

-uptake into storage vessels

-release of NT

-binding to receptor

-degradation of acetylcholine

-recycling of choline

why do we degrade excess acetylcholine in the synapse?

so its not hanging around and binding to everything

Direct acting cholinergic agonists info

-ex: acetylcholine (miochol-e)

-binds DIRECTLy to receptors

-but it lasts longer than the one we make

-has both muscarinic and nicotinic activity

Direct acting cholinergic agonists effects

-decrease HR and cardiac output (BP)

-increase secretion (salivary, intestinal, bronchiolar, urinary)

-miosis (constricted pupils)

-bronchoconstriction

common direct cholinergic agonist side effects

(think "rain forest!")

-diarrhea

-diaphoresis (sweating)

-miosis (constricted pupils)

-urinary urgency

-nausea

irreversible indirect acting cholinergic agonist info

-ex: echothiophate (phosoline iodide)

-MOA: permanently inactivates acetylcholinesterase

-no way to reactivate it (body has to make more = lots of s/e)

-not much we can do to fix it

cholinergic crisis

excessive cholinergic stimulation (b/c it is permanently bound there!) and depolarizing neuromuscular blockade

treatment for cholinergic crisis?

-atropine: a cholinergic antagonist!

-pralidoxime: to reverse the inhibition of cholinesterase --> break down ACh (only works with the reversible ones, some aren't reversible)

-diazepam: to suppress convulsions

-mechanical ventilation

what indirect acting cholinergic agonist can be used as a bioweapon due to its irreversible binding properties leading to cholinergic effect?

Seran

cholinergic agonist examples

-acetylcholine

-bethanechol

-carbachol

-pilocarpine

-physostigmine

-neostigmine

-rivastigmine, galatamine, donepezil (we know these!)

Acetylcholine is used

to produce miosis in opthalmic surgery

Bethanechol is used

in treatment of urinary retention

it binds preferentially at muscarinic receptors

Carbachol is used

topically to reduced intraocular pressure in glaucoma (esp if tolerant to pilocarpine)

also produces miosis during ocular surgery

binds both muscarinic and nicotinic receptors

pilocarpine

reduces intraocular pressure in glaucoma

binds preferentially at muscarinic receptors

tertiary amine can penetrate the CNS

physotigmine

-increases intersital & bladder motility

-reverses CNS & cardiac effects of TCAs

-reverses CNS effects of atropine

-tertiary amine can enter the CNS

neostigmine

-prevents post op abd. distention and urinary retention

-used in tx for myasthenia gravis

-antidote for competitve neuromuscular blockers

-intermed duration of action

rivastigmine, galatamine, donepezil

-first line tx for alz. modest benefits though

-can be used in conjuncture with memantine (NMDA agonist) in mod-severe disease

types of cholinergic antagonist

muscarinic blockers

ganglionic blockers

neuromuscular blockers

of the cholinergic antagonists, ______ are the most useful clinically

muscarinic blockers

muscarinic blockers

block muscarinic receptors of PS nerves (eye, GI, bladder, CV, saliva)

ganglionic blockers

prefer nicotinic receptors of PS/S ganglia (nicotine)

neuromuscular blockers

interfere w/ efferent impulse to skeletal muscle, paralysis (anesthesia)

antimuscarinic agents info

ex: atropine

-acts both centrally and peripherally

-greatest effect is in the bronchial tissue, salivary gland, sweat glands, and heart

therapeutic use of atropine

-ophthalmic exams/procedures

-bradycardia

-cholinergic crisis!

t/f atropine's use is dependent on its dose

true!

low dose of atropine

cardiac slowing, dryness of mouth, inhibition of sweating

intermediate dose of atropine

-rapid heart rate (treats bradycardia rmbr),

-marked dryness of mouth

-dilation of pupil (opthalmic exams!)

high dose of atropine

hallucinations

-delirium

-coma

antimuscarinic side effects

its a dirty drug, for every one good thing it does, it causes like 4 bad things including

-memory problems

-dry mouth

-blurred vision

-constipation/dysuria

-drowsiness

-sedation

ganglionic blockers info

ex: nicotine

-these are nicotinic receptors

nicotine therapeutic use

there is none

-stimulates the release of every neurotransmitter (why its so addicting)

-increased BP and HR

neuromuscular blocking agents info

-block transmission between motor nerve endings and nicotinic receptors on skeletal muscle

-used in anesthesia (or to harm ppl)

2 kinds of neuromuscular blocking agents

-nondepolarizing

-depolarizing

nondepolarizing neuromuscular blocking agents

-are competitive (ex: curare, pancuronium)

-block ACh, muscle can't contract (this can be overcome with cholinesterase inhibitors = incr ACh)

-lots of drug interactions

depolarizing neuromuscular blocking agents

-are noncompetitive (ex: succinylocholine)

-initially activates the receptor (like an agonist!) the muscle contracts, but then... it just sits there and doesn't leave, no ACh can come in!

-no further muscle impulses!

-rapid short lived paralysis

Anticholinergic drug examples

-Trihexyphenidyl and Benztropine

-Oxybutynin (and more)

-Cyclopentolate (and more)

-Atropine

-Scopolamine

-Glycopyrrolate (and more)

-Nicotine

Trihexyphenidyl and Benztropine

-parkinsons

-antipsychotic induced effects

Oxybutynin (and friends)

-tx of overactive bladder

Cyclopentolate, tropicamide, atropine

-ophthalmology for mydriasis (dilation)

scoplamine

-motion sickness

glycopyrrolate, ipratropium, (and freinds)

COPD

Nicotine

smoking cessation

Which of the following drugs is correctly matched to its mechanism of action?

Pyridostigmine—inhibitor of AChE enzyme

A patient develops urinary retention after an abdominal surgery. Urinary obstruction was ruled out in this patient. Which of the following strategies would be helpful in promoting urination?

Inhibiting cholinesterase enzyme

If an ophthalmologist wants to dilate the pupils for an eye examination, which of the following drugs/class of drugs is theoretically useful?

Muscarinic receptor inhibitor (antagonist)

Which of the following drugs would be most useful in treating xerostomia?

Pilocarpine