MCMP 407 ANS Why Study the Autonomic Nervous System? Disease State
MCMP 407 Why Study the Autonomic Nervous System? Medicinal Chemistry Pathophysiology Therapeutics ANS Disease State Management Pharmacology MCMP 407 Organization of The Nervous System Central Nervous System Autonomic Nervous System Sympathetic Peripheral Nervous System Somatic Nervous System Parasympathetic MCMP 407 How do we define neuron types in the ANS? Parasympathetic O C CH3 Sympathetic HO CH3 CH2 O CH2 N CH3 HO CH Acetylcholine CH3 NH 2 OH Norepinephrine HO CH3 H3C CH2 O CH2 Muscarine N (Noradrenaline) CH3 HO CH3 HO N CH3 N CH CH2 OH Epinephrine (Adrenaline) Nicotine NH CH3 MCMP 407 Parasympathetic Ganglionic Synapse Acetylcholinesterase Na+ aba ACH Action Potential Na+ Preganglionic neuron Nicotinic Receptor Postganglionic neuron MCMP 407 Parasympathetic Organ Synapse Acetylcholinesterase Effector Organ Na+ K+ G Action Potential ACH Muscarinic Receptor Postganglionic neuron MCMP 407 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 MCMP 407 Sympathetic Ganglionic Synapse Acetylcholinesterase Na+ aba ACH Action Potential Na+ Preganglionic neuron Nicotinic Receptor Postganglionic neuron MCMP 407 Sympathetic Organ Synapse Effector Organ Na+ Action Potential NE Adrenergic Receptor Postganglionic neuron MCMP 407 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 MCMP 407 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 MCMP 407 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? MCMP 407 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 MCMP 407 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
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