Drugs For The ANS I Flashcards
Details of the somatic NS?
A single myelinated fiber from
ANS to skeletal m
Uses ACh
Details of the ANS (efferent)?
2 neurons in series which syn in ganglia, inn smooth, heart and glands
Only pregang is myelinated
What’s the NT in all ganglia and post gang parasympathetic fibers?
ACh
What’s the NT in most post gang sympathetic fibers?
Norepinephrine
Where do SNS pregang fibers exit CNS in the SC?
Thoracic and lumbar regions
Where do PNS pregang fibers exit CNS in the SC?
3, 7, 9, 10 CN and 2-4th sacral nerves
Short post gang fibers, localized effect
Adrenal medulla?
- A special sympathetic ganglion
- inn by pregang sym fibers that release ACh
- release epi (a hormone) from chromaffin cells into blood
- sweat glands for temp control (post gang release ACh to A+ eccrine sweat glands)
PNS effects
Local, positive
Constricts pupils, focuses on near objects
Erection
SNS effects
Diffuse, negative
Bronchodilation
I- labor uterine contractions
5 steps of neurotransmission?
Synthesis, storage, release, binding, inactivation of transmitter
Post ganglionic neurotransmission?
Cholinergic (ACh)
Adrenergic (NE)
ACh syn?
Acetyl CoA plus choline via choline acetyltransferase
Post gang mech?
ACh release to bind M3 ➡️ more Ca ➡️ effect on tissue
Where is ACh made and stored?
Cytosol
Vesicles, where it accumulates
Steps of cholinergic transmission?
AP depolarizes mem, opens volt gated Ca channels, Ca influx ➡️ expcytosis, ACh vesicles fuse and release contents
Empty vesicles are recycled
A+ of M2 receptors on nerve term can I- further release of ACh ***feedback I-
What does botulinum toxin block?
Exocytosis (ACh vesicles fusing and releasing contents)
How does depolarization happen?
AP ➡️ depolarization ➡️ opens volt Ca channels
What are muscarinic receptors?
A class of ACh receptors
1-5
G pro linked
A+ of M2 receptors on nerve terminal can I- further release of ACh (feedback inhibition)
A+ of M3 receptors on target tissue ➡️ increase in cell Ca
ACh is the only agonist for these receptors
What is the anta for muscarinic receptors?
ACh
Where is AChase found?
Post syn mem
What does BChE do?
I- ACh re entering blood
Steps to make Epi and NE?
Tyrosine to Dopa (Catechol) to Dopamine to E and NE
Tyr hydroxylated to Dopa is rate limiting step
Remove carboxyl group to get DA
DA taken up by storage vesicles
What neurons use which NT?
DA neurons: DA is NT, stored
Adrenergic neurons: DA to NE in vesicle
Adrenal Med: NE to Epi via a methyl group
How is NE stored?
In high conc w/ ATP
In adrenergic neurotransmission what I- excess NE release via feedback I-?
A+ of alpha2 receptors on the nerve terminal
What are the adrenergic receptors? What are the ago?
Alpha1,2 and beta 1,2
NE and epi
What do epi and NE bind?
Epi: all adrenergic receptors
NE: all except B2
DA: DA D receptors, B1 and a1 adrenergic receptors
