期刊
SCANDINAVIAN JOURNAL OF UROLOGY AND NEPHROLOGY
卷 35, 期 -, 页码 35-43出版社
INFORMA HEALTHCARE
DOI: 10.1080/003655901750174872
关键词
urethra; urethral sphincter; bladder; reflex pathways; afferent nerves; neurotransmitters
资金
- NIDDK NIH HHS [DK-51402, DK-49430] Funding Source: Medline
- NINDS NIH HHS [N01-NS-8-2301] Funding Source: Medline
- NATIONAL INSTITUTE OF DIABETES AND DIGESTIVE AND KIDNEY DISEASES [R01DK051402, R37DK049430, R01DK049430] Funding Source: NIH RePORTER
- NATIONAL INSTITUTE OF NEUROLOGICAL DISORDERS AND STROKE [N01NS082301] Funding Source: NIH RePORTER
Coordination between the urinary bladder and the urethra is mediated by multiple reflex pathways organized in the brain and spinal cord. Some reflexes promote urine storage; whereas other reflexes facilitate voiding. During bladder filling, activation of mechanoreceptor afferent nerves in the bladder wall triggers firing in the cholinergic efferent pathways to the external urethral sphincter (EUS) and in sympathetic adrenergic pathways to the urethral smooth muscle. These storage reflexes are dependent upon interneuronal circuitry in the spinal cord. During voiding the spinal storage reflexes are inhibited by supraspinal mechanisms which originate in the pontine micturition center. Glutamatergic, serotonergic and alpha(1) adrenergic excitatory transmission as well as GABAergic/glycinergic inhibitory transmission have been implicated in the central control of sphincter reflexes. During voiding, a parasympathetic nitrergic inhibitory input to the urethral smooth is activated. This reflex mechanism which is triggered by bladder afferents persists in paraplegic rats and therefore must be mediated at least in part by spinal interneuronal circuitry. In female rats, the parasympathetic nitrergic pathway is prominent; but in male rats it is obscured by a dominant parasympathetic cholinergic excitatory input to the urethral smooth muscle. The function of the cholinergic pathway in voiding is uncertain. Stimulation of urethral afferents can also influence bladder activity. Contraction of the external urethral sphincter activates afferents that inhibit reflex bladder contractions; whereas infusion of fluid through the urethra facilitates bladder contractions. These reflexes are also organized in the spinal cord and presumably play a role in urine storage and elimination. Alterations in primitive bladder-to-urethra and urethra-to-bladder reflex mechanisms may contribute to neurogenic bladder dysfunction.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据