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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1-2
pubmed:dateCreated
2000-12-28
pubmed:abstractText
The role of spinal alpha(1)-adrenergic mechanisms in the control of urinary bladder function was examined in urethane (1.2 g/kg s.c.) anesthetized and decerebrate unanesthetized female Sprague-Dawley rats (250-320 g). Bladder activity was recorded via a transurethral catheter during continuous infusion (0.21 ml/min) cystometrograms or under isovolumetric conditions. All drugs were administered intrathecally at the L(6)-S(1) segmental level of spinal cord. During cystometrograms, 3 or 30 nmol of phenylephrine (alpha(1)-adrenergic agonist) did not alter bladder activity; whereas 300 nmol increased the intercontraction interval by 98% and pressure threshold for inducing micturition by 115%, but did not change bladder contraction amplitude. A large dose of phenylephrine (3000 nmol) completely blocked reflex voiding and induced overflow incontinence at a high baseline pressure (mean: 33 cmH(2)O; range: 28-42 cmH(2)O). Under isovolumetric conditions, 3-30 nmol of phenylephrine abolished bladder activity for 22-45 min; whereas smaller doses (0.003-0.3 nmol) were inactive. Doxazosin (50 nmol), an alpha(1)-adrenergic antagonist, decreased intercontraction intervals but did not change bladder contraction amplitude during cystometrograms. Under isovolumetric conditions this dose of doxazosin increased bladder contraction frequency and decreased bladder contraction amplitude. Smaller doses (5 or 25 nmol) of doxazosin did not alter bladder activity. These studies suggest that two types of spinal alpha(1)-adrenergic mechanisms are involved in reflex bladder activity: (1) inhibitory control of the frequency of voiding reflexes presumably by regulating afferent processing in the spinal cord and (2) facilitatory modulation of the descending limb of the micturition reflex pathway.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Nov
pubmed:issn
0006-8993
pubmed:author
pubmed:issnType
Print
pubmed:day
3
pubmed:volume
882
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
36-44
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
2000
pubmed:articleTitle
Role of spinal alpha(1)-adrenergic mechanisms in the control of lower urinary tract in the rat.
pubmed:affiliation
Department of Pharmacology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA. pxn15164@nifty.ne.jp
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't