Autonomic Pharmacology Flashcards
All preganglionic sympathetic neurons originate in the spinal cord from segments _____
T1 and L2
In the Parasympathetic Nervous System,
preganglionic neurons originate from the
brainstem and the sacral spinal cord and travel peripherally via
○ Cranial nerves III, VII, IX, and X
■ About 75% are in the Vagus Nerve
○ Pelvic splanchnic nerves
Parasympathetic preganglionic fibers travel a
relatively ____ distance before synapsing on the postganglionic neurons
long
Postganglionic neurons reside in ganglia and
plexuses located in the wall of the effector organ or in very close proximity to the tissue in which system?
Parasympathetic NS
Neurons that release _____ are called Cholinergic fibers
acetylcholine
Neurons that release norepinephrine are called _____
Adrenergic fibers
For both the sympathetic and parasympathetic nervous systems, all
preganglionic neurons are _____
cholinergic
most of the postganglionic
sympathetic neurons are ____ fibers while most all of the postganglionic parasympathetic neurons are ____ fibers
adrenergic; cholinergic
In order for a neurotransmitter released from a postganglionic fiber to stimulate an effector organ, it must ____
bind to a specific receptor on the effector organ cells
Two types of cholinergic receptors
Muscarinic and Nicotinic
Nicotinic receptors are ligand-gated ion
channels found at the NMJ of skeletal
muscle, and all synapses of _____
preganglionic and postganglionic cells (all ANS)
Muscarinic receptors are found on effector
cells that are stimulated by _____
postganglionic cholinergic neurons (all parasympathetic, a few sympathetic fibers)
Five subtypes of cholinergic receptors
○ M1 - Muscarinic, sweat glands of the skin
○ M2 - Muscarinic, SA and AV nodes of the heart; involved in slowing of the heart rate and conduction.
○ M3 - Muscarinic, smooth muscles and glands of various organ systems; involved in pupil constriction, contraction of
bronchioles, increased GI motility, stimulation of glandular secretions, urethral sphincter relaxation, etc.
○ NN - Nicotinic (nerve type), located on postganglionic cells.
○ NM - Nicotinic (muscle type), located at neuromuscular junction
The only cholinoreceptor involved in sympathetic function is ___
M1
Two classes of Adrenergic receptors
Alpha receptors are of two types: Alpha-1 and Alpha-2.
Beta receptors are of three types: Beta-1, Beta-2, and Beta-3.
Alpha receptors
Both Alpha-1 and 2 are found throughout the body on many effector organs; Alpha-1 is especially prominent in blood vessels
and intestinal musculature
Beta receptors
While there is some overlap, we generally think of Beta-1 as primarily cardiac, Beta-2 primarily pulmonary, and Beta-3 as minimally involved (thermoregulation).
○ Beta-2 is also found in blood vessels, intestinal musculature, the uterus, etc
Norepinephrine vs. epinephrine effects on alpha and beta receptors
Norepinephrine excites both, but mainly alpha receptors; Epinephrine excites both adrenergic receptors equally
T/F Most organ systems are dominantly controlled by either the sympathetic or the parasympathetic system.
T
Cholinergic agonists - Direct acting
○ Bethanechol
○ Pilocarpine (Salagen, Isopto Carpine)
○ Nicotine
○ Varenicline (Chantix)
Cholinergic agonists - Choninesterase inhibitors
○ Pyridostigmine (Mestinon)
○ Donepezil (Aricept)
Cholinergic agonists are also known as ____
Cholinomimetics
MICSAF - Behanechol
MOA: Direct acting, muscarinic
Indication: Neurogenic ileus and urinary retention
Contraindication: Known GI or bladder obstruction, recent GI or bladder surgery,
Side effects: Depending on where the drug is acting, side effects can
include blurry vision, nausea/vomiting, diarrhea, salivation,
sweating, bradycardia, bronchial secretions, etc *for all CA’s
MICSAF - Pilocarpine (Salagen,
Isopto Carpine)
MOA: Direct acting, muscarinic
Indications: Glaucoma (eye drops) and Sjogren’s-related xerostomia (tabs)
Contraindications: Acute iritis (tabs and eye drops), angle-closure glaucoma (tabs)
