Why Study the Autonomic Nervous System?

1. Pathophysiology Why Study the Autonomic Nervous System? Medicinal Chemistry ANS Therapeutics Pharmacology 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. a b a Parasympathetic Ganglionic Synapse Acetylcholinesterase Ca2+ Na+ ACH Action Potential Nicotinic Receptor Na+ Preganglionic neuron Postganglionic neuron

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

7. 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 Summary of parasympathetic neurons and synapses

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

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

11. 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 Summary of sympathetic neurons and synapses

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. 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 How do drugs influence the ANS?

15. 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 Classification of drugs affecting the ANS