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In the autonomic nervous system, fibers from the ganglion to the effector organ are called postganglionic fibers. ==Neurotransmitters== The neurotransmitters of postganglionic fibers differ: * In the parasympathetic division, neurons are ''cholinergic'' (that is, acetylcholine is the primary neurotransmitter). * In the sympathetic division, neurons are mostly ''adrenergic'' (that is, epinephrine and norepinephrine function as the primary neurotransmitters). Two exceptions to this rule are the sympathetic innervation of sweat glands and arrectores pilorum muscles where the neurotransmitter at both pre and post ganglionic synapses is acetylcholine and the vessels in the renal cortex where dopamine is used as the main neurotransmitter. Another exception is the sympathetic innervation of the medulla of the adrenal glands, which is accomplished by preganglionic fibers, and subsequently uses acetylcholine as a neurotransmitter. The cells of the adrenal medulla are actually modified postganglionic neurons which secrete epinephrine and norepinephrine directly into the blood stream rather than into a synapse. * In both divisions of the autonomic nervous system, postganglionic neurons express nicotinic acetylcholine receptors to receive signals from preganglionic neurons. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Postganglionic nerve fibers」の詳細全文を読む スポンサード リンク
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