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sympathetic nerve terminals at the neuromuscular junction and in the parasympathetic ganglia3,6. Activation of these receptors on the nerve terminals
can enhance (through M1 receptors) or suppress (through M4 receptors) transmitter release, depending on the intensity of the neural firing. Non-cholinergic excitatory
transmission is mediated by ATP actions on P2X purinergic receptors in the detrusor muscle7. Inhibitory input to the urethral smooth muscle is mediated by nitric
oxide (NO) that is released by parasympathetic nerves4. *University College London,
Department of
Uro-Neurology, London,
WC1N 3BG, UK.
‡Division of Geriatric
Medicine and Institute on
Aging, University of
Pittsburgh, Pittsburgh,
Pennsylvania 15213, USA.
§Department of
Pharmacology, University of
Pittsburgh Medical School,
Pittsburgh, Pennsylvania
15261, USA.
Correspondence to C.J.F.
doi:10.1038/nrn2401
Pudendal nerve
A nerve that innervates
the external genitalia and the
urethral and anal sphincters.
Detrusor muscle
The smooth muscle of the
bladder.
The neural control of micturition
Clare J. Fowler*, Derek Griffiths‡ and William C. de Groat §
Abstract | Micturition, or urination, occurs involuntarily in infants and young children until the age of 3 to 5 years, after which it is regulated voluntarily. The neural circuitry that controls this process is complex and highly distributed: it involves pathways at many levels of the brain, the spinal cord and the peripheral nervous system and is mediated by multiple neurotransmitters. Diseases or injuries of the nervous system in adults can cause the re-emergence of involuntary or reflex micturition, leading to urinary incontinence. This is a major health problem, especially in those with neurological impairment. Here we review the neural control of micturition and
how disruption of this control leads to abnormal storage and release of urine.
REVIEWS
nat ure reviews | neuroscience volume 9 | june 2008 | 453
© 2008 Nature Publishing Group
Nature Reviews | Neuroscience
Bladder Ureter
L1
IMP
SHP
T9
S1
SN
PEL
PP
HGN
Pudendal
nerve
a b
Pelvic nerve
(parasympathetic)
Hypogastric
nerve (sympathetic)
Pudendal nerve
(somatic)
Bladder
M3 receptor (+)
β3 receptor (–)
α1 receptor (+)
Urethra
External urethral
sphincter
Urogenital
diaphragm
Detrusor
muscle
NA
NA
ACh
ACh
Nicotinic receptor (+)
Onuf’s nucleus
A nucleus in the sacral cord
that contains the anterior horn
cells that innervate the
sphincters.
Urothelium
The superficial layer of the
bladder.
Somatic cholinergic motor nerves that supply the striated muscles of the external urethral sphincter arise in S2–S4 motor neurons in Onuf’s nucleus and reach the periphery through the pudendal nerves1,2 (FIG. 1a). A medially placed motor nucleus at the same spinal level supplies axons that innervate the pelvic floor musculature.
Sensations of bladder fullness are conveyed to the spinal ord by the pelvic and hypogastric nerves1,8, whereas sens本论文由英语论文网提供整理，提供论文代写，英语论文代写，代写论文，代写英语论文，代写留学生论文，代写英文论文，留学生论文代写相关核心关键词搜索。