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236 SEcTIoN II Pharmacology ` PHARMACOLOGY—AUTONOMIC dRUGS Pharmacology ` PHARMACOLOGY—AUTONOMIC dRUGS

` PHARMACOLOGY—AUTONOMIC dRUGS

Autonomic receptors

Brainstem Smooth muscle, gland
Parasympathetic ACh N Post ACh M cells, nerve terminals,
Pre (long) N (short) cardiac muscle
Spinal cord

ACh N ACh M Sweat glands
Pre (short) N Post (long)
α 1 Smooth muscle, gland
ACh N N NE α 2 cells, nerve terminals,
β 1 cardiac muscle
Sympathetic
ACh N N D D 1 Renal vasculature
smooth muscle
α 1
Adrenal medulla NE α 2
β
ACh N N Blood α 1 1 Cardiac muscle, vessels
Catecholamine α 2
transmission Epi β 1
β
2
ACh N Skeletal muscle
SOMATIC Voluntary motor nerve M
Neuromuscular
junction
Pelvic splanchnic nerves and CNs III, VII, IX and X are part of the parasympathetic nervous system.
Adrenal medulla is directly innervated by preganglionic sympathetic fibers.
Sweat glands are part of the sympathetic pathway but are innervated by cholinergic fibers
(sympathetic nervous system results in a “chold” sweat).

Acetylcholine Nicotinic ACh receptors are ligand-gated Na /K channels. Two subtypes: N N (found in autonomic
+
+
receptors ganglia, adrenal medulla) and N M (found in neuromuscular junction of skeletal muscle).
Muscarinic ACh receptors are G-protein–coupled receptors that usually act through 2nd
messengers. 5 subtypes: M 1–5 found in heart, smooth muscle, brain, exocrine glands, and on sweat
glands (cholinergic sympathetic).

FAS1_2019_05-Pharmacology.indd 236 11/7/19 4:08 PM