Lecture 11: Introduction to Autonomic Pharmacology Flashcards
What are the two divisions of the efferent NS
Somatic and autonomic
What does the somatic NS do
Controls conscious movements, pertains to movement and posture
What does the autonomic NS do
Unconsciously controlled, pertains to control of viscera, maintains physiological homeostasis
What is the main NT in the sympathetic NS
Noradrenaline
What is the main NT in the PNS
Acetylcholine
Where do PNS preganglionic fibers originate
Medulla, brain stem and sacral intumescence
PNS preganglionic fibers are ___ while post-ganglionic fibers are ___
Long, short
What is the most important PNS nerve
Vagus, CN X
SNS or PNS: craniosacral efferent
PNS
SNS or PNS: thoracolumbar efferents
SNS
SNS preganglionic fibers are __ while Postganglionic fibers are ___
Short, long
Preganglionic neurons leave the spinal cord and terminate in the ___
Paravertebral chain
What does the paravertebral chain allow for in terms of transmission
Rapid, coordinated transmission through entire sympathetic system
What is the only endogenous NT that stimulates the PNS
Acetylcholine
T or F: acetylcholine acts in both the SNS and PNS
True
T or F: epinephrine/adrenaline act in both the PNS and SNS
False, exclusively in SNS
What are the 3 endogenous NT in the SNS
- Epinephrine
- Norepinephrine
- Dopamine
What are the Nm receptors
Receptors stimulated by acetylcholine in the neuromuscular junction
Where are the Nn receptors
- Postsynaptic ganglionic junctions
- adrenal medulla
Muscarinic receptors are present in all SNS or PNS post synaptic junctions
PNS
Where are muscarinic receptors located in SNS post synaptic junctions
Sweat glands
What species does not have muscarinic receptors in their sweat glands and what NT acts on their receptors
Horses, NE acts
Where are alpha1 receptors found
Vasculature, GI tract, trigone of urinary bladder, spleen, piloerector muscles, male genitalia
Where are alpha 2 receptors found
Sympathetic pre-synaptic nerve terminals
Some endothelium, platelets, pancreatic islets and kidneys
Where are B1 receptors found
Heart, GI tract, urinary bladder, kidney and uterus
Where are B2 receptors found
Bronchioles, Heart, vasculature, liver, pancreas, sympathetic, pre-synaptic nerve terminals and fat cells
NE is released from majority of ___ganglionic SNS nerves
Post ganglionic
NE primarily stimulates what receptor
Alpha1 with a little bit of B1
Where is epinephrine released from
Adrenal medulla, circulates blood acts more like a hormone
Where can epinephrine act
Nerve terminals or directly on vasculature
What receptors does epinephrine stimulate
Alpha and beta receptors
What does high dose dopamine activate
Alpha receptors
What does a medium dose of dopamine activate
Cardiac B1 receptors- increase HR and contractility
What does a low dose of dopamine activate
DA receptors in renal vasculature, vasodilation
SNS or PNS: maintains blood pressure
sympathetic
Normally there is no ___stimulation to the vasculature, except…
PNS, except the uninnervated M receptors that can be activated by M receptor agonist (ex: bethenacol)
What receptors does SNS stimulation of skin and reservoir veins activate and what is the result
Alpha1- vasoconstriction (increase BP)
What receptors does SNS stimulate of skeletal muscle activate
B2, alpha 1
What receptor does NE activate in Skeletal muscle and what is the result
Activates alpha1, vasoconstriction
What receptors does high dose epinephrine act in skeletal muscle and what is the result
Alpha 1, vasoconstriction
What does low dose epinephrine act on and what is the result
B2, vasodilation
What receptors does SNS stimulation of visceral and renal blood vessels activate
Alpha1, DA, and B2
What receptor does NE act on in visceral and renal blood vessels and what is the result
Alpha1, vasoconstriction
What does high dose epinephrine do to blood vessels in visceral and renal
Vasoconstriction, acts on alpha 1
What does low does epinephrine do to blood vessels in viscera and renal
B2, vasodilation
What does low dose dopamine do to vessels in renal system and viscera and what receptors
Acts on DA receptors, vasodilation
What does high dose dopamine act on in visceral and renal system and what receptors
Acts on alpha1, vasoconstrict
How does the PNS system impact the cardiovascular system
Decreases HR via the vagus nerve and therefore decreases CO
what does stimulation of alpha1 do to the CV system
Increase peripheral vascular resistance via vasoconstriction and BP
What does stimulation of B2 do to CV system
Decrease peripheral vascular resistance via vasodilation and decrease BP
What does B1 stimulation do to cardiac output and how does this work
Increase cardiac output by increase contractility and HR
What does NE administration do to BP and HR
Increase BP and slight initial increase in HR then decrease via baroreceptor reflex
Can you feel the difference in increase BP after administration of NE
Not always, if the systolic and diastolic difference is equal
What receptor does NE mainly act on
Alpha 1 (little bit of beta1)
Describe how the baroreceptor reflex works in an increased BP
- Increased BP perceived by baroreceptor in aortic arch and carotid artery
- Afferent inputs sent to medulla
- Decrease SNS and increase PNS activity
- Decrease HR and CO
What nerve innervates the PNS division of the respiratory system
vagus
What receptors are located in the PNS division of the respiratory system and what is the result of stimulation
M receptors, if stimulated cause bronchoconstriction and increased mucus secretion
What receptors are in the SNS division of respiratory system and what is the result of stimulation
B2 receptors, bronchodilation
What nerve stimulates salivary glands in PNS division of GI
Facial nerve
What is the role of vagus nerve in PNS division of GI
Relax sphincters, stimulate GI motility and gastric acid secretion
What is the role of SNS division in GI
Reduce salivary secretions, reduce GI motility and gastric acid secretions. Contract urinary sphincter
How does SNS stimulation of GI impact glycogenolysis and gluconeogenesis
Increases
___secretion of pancreatic acinar cells and ___ secretion of islet cells in SNS division of GI
Decrease, increase
What is the PNS control over GU system
Erection, relax urinary sphincter at trigone and contract urinary bladder Fundus
What is the role of the SNS system in GU
Uterine contractions, ejaculation, increase renin secretion, contracts urinary sphincter and relax fundus
What does the PNS system do to the eyes
Increase tear formation, contract ciliary muscles to accommodate for near field, miosis
The PNS system opens the anterior chamber angle of the eye, what is the result of this action
Increases outflow of aqueous humor through the canal of schlemn and decreases IOP
What do the alpha receptors do in SNS division of eye
Cause mydriasis
What do the Beta receptors do in SNS division of the eyes
Increase aqueous humor production and increase IOP
Relax cilary muscles causing accommodation for far field
What is the role of alpha receptors in the spleen
Contract
What is the role of B2 receptors in the spleen
Relaxation
What type of secretion do sweat glands have (what NT)
Cholinergic in most species
**B2 mediated in horses with NE
What receptors mediate contraction int he piloerector muscles
Alpha