1. Why Study the Autonomic Nervous System?
Pathophysiology
Medicinal
Chemistry
ANS
Therapeutics
Pharmacology
Just a few reminders before we get started
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Disease State
Management

2. Organization of The Nervous System
Central Nervous System
Peripheral Nervous System
Autonomic Nervous System
Somatic Nervous System
Sympathetic
Parasympathetic

3. How do we define neuron types in the ANS?
Parasympathetic
Sympathetic
Acetylcholine
Norepinephrine
(Noradrenaline)
Muscarine
Epinephrine
(Adrenaline)
Nicotine

5. Parasympathetic Ganglionic Synapse
Acetylcholinesterase
Ca2+
Na+
ACH a b
Action Potential
Nicotinic
Receptor
Na+
Preganglionic neuron
Postganglionic neuron

6. Parasympathetic Organ Synapse
Acetylcholinesterase
Ca2+
Effector
Organ
Na+ K+ G
Action Potential
ACH
Muscarinic
Receptor
Postganglionic neuron

7. Summary of parasympathetic neurons and synapses
Preganglionic neurons
Long
Synapse with postganglionic neurons at or near organ
Release acetylcholine (ACH) to activate nicotinic receptors on postganglionic neurons
Postganglionic neurons
Short
Synapse on the target organ
Release acetylcholine (ACH) to activate muscarinic receptors on the target organ

9. Sympathetic Ganglionic Synapse
Acetylcholinesterase
Ca2+
Na+
ACH a b
Action Potential
Nicotinic
Receptor
Na+
Preganglionic neuron
Postganglionic neuron

10. Sympathetic Organ Synapse
Ca2+
Effector
Organ
Na+ G NE
Action Potential
Adrenergic
Receptor
Postganglionic neuron

11. Summary of sympathetic neurons and synapses
Preganglionic neurons
Short
Synapse with postganglionic neurons near spinal cord
Release acetylcholine (ACH) to activate nicotinic receptors on postganglionic neurons
Postganglionic neurons
Long
Synapse on the target organ
Release norepinephrine to activate adrenergic receptors on target organs

12. Exceptions in the sympathetic nervous system:
Sweat glands:
Postganglionic neurons involved with stress-related excretion release norepinephrine (“sweaty palms”)
Postganglionic neurons involved with thermoregulation release acetylcholine

13. Exceptions in the sympathetic nervous system:
Kidneys:
Postganglionic neurons to the smooth muscle of the renal vascular bed release dopamine
Adrenal gland:
Preganglionic neurons do not synapse in the paraverterbral sympathetic ganglion
Preganglionic neurons synapse directly on the adrenal gland, release acetylcholine, and activate nicotinic receptors on the adrenal gland
Adrenal glands release epinephrine into systemic circulation
Most postganglionic sympathetic
neurons release what
neurotransmitter?

14. How do drugs influence the ANS?
Mimic or block the effects of the two primary neurotransmitters, Acetylcholine and Norepinephrine/Epinephrine
Drugs that mimic neurotransmitters are referred to as “receptor agonists”
These drugs activate receptors
Drugs that block neurotransmitters are referred to as “receptor antagonists”
These drugs block the endogenous neurotransmitters from activating receptors

15. Classification of drugs affecting the ANS
Parasympathetic nervous system
Mimic acetylcholine = cholinergic = muscarinic agonists = parasympathomimetic
Block acetylcholine = anticholinergic = muscarinic antagonist = parasympatholytic
Sympathetic nervous system
Mimic norepinephrine = adrenergic = adrenergic agonist = sympathomimetic
Block norepinephrine = antiadrenergic = adrenergic antagonist = sympatholytic