Document Detail


The presence and function of phosphodiesterase type 5 in the rat myometrium.
MedLine Citation:
PMID:  14749671     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
OBJECTIVE: Cyclic nucleotide phosphodiesterases (PDEs) are a diverse enzyme group with multiple regulatory properties and wide tissue distribution. Such activity includes cyclic adenosine (cAMP) and guanosine monophosphate (cGMP) breakdown. The type 5 isoform (PDE-5, cGMP specific) is the target of specific antagonists (ie, sildenafil, Viagra). We tested the hypothesis that PDE-5 is present in rat myometrium and modulates myometrial activity. STUDY DESIGN: Full-thickness uterine wall was collected from nonpregnant (n=3) and pregnant Sprague-Dawley rats on days 10 (n=4), 17 (n=6), 22 nonlabor (n=5), and 22 during term labor (TL, n=4). Preterm labor (PTL, n=3) was induced in some animals on day 16 with 15 mg/kg mifepristone (RU 486). Tissue samples were prepared for Western blotting using a monoclonal antibody against rodent PDE-5. In a second series, cumulative doses of sildenafil (0.005, 0.05, 0.5, 5 mg/kg, intraperitoneal) were administered and the effect on uterine contractility recorded in vivo during term (TL, n=7) and preterm labor (PTL, n=6). Saline solution-injected rats provided temporal control. Uterine contractility was estimated from intrauterine pressure (IP) measured electronically with a sensor tip pressure catheter. Heart rate was recorded simultaneously using electrodes attached to the chest and connected to the same data acquisition system. RESULTS: PDE-5 immunoreactivity was present in the nonpregnant rat uterus and at all gestational times studied, although the expression was unaffected by either pregnancy or the state of labor (preterm or term). A dominant antibody-specific band was identified at 86 kd in the uterine samples, contrasting with lung where the 100-kd PDE-5 isoform was most abundant. Two additional lower molecular weight (55 and 32 kd) bands were also identified as antibody specific. Despite the lack of change in PDE-5 during pregnancy, sildenafil reduced IP during TL and PTL beginning at 0.5 mg/kg. The highest dose of sildenafil reduced IP during both TL and PTL by 45% and 59% of baseline, respectively (two-way analysis of variance, P<.01). This effect was not accompanied by changes in heart rate. CONCLUSION: PDE-5 is constitutively present in the rat uterine wall. There was no observed change in the PDE-5 protein expression throughout pregnancy. In contrast to the lung, the uterus expresses an 80-kd PDE-5 isoform. Sildenafil in pharmacologic doses inhibits mechanical uterine activity and might be of benefit if selectively used for treatment of preterm labor.
Authors:
Catalin S Buhimschi; Robert E Garfield; Carl P Weiner; Irina A Buhimschi
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  American journal of obstetrics and gynecology     Volume:  190     ISSN:  0002-9378     ISO Abbreviation:  Am. J. Obstet. Gynecol.     Publication Date:  2004 Jan 
Date Detail:
Created Date:  2004-01-29     Completed Date:  2004-02-25     Revised Date:  2007-11-15    
Medline Journal Info:
Nlm Unique ID:  0370476     Medline TA:  Am J Obstet Gynecol     Country:  United States    
Other Details:
Languages:  eng     Pagination:  268-74     Citation Subset:  AIM; IM    
Affiliation:
Department of Obstetrics, Gynecology, and Reproductive Sciences, Yale University, New Haven, CT 06520, USA. catalin.buhimschi@yale.edu
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MeSH Terms
Descriptor/Qualifier:
3',5'-Cyclic-GMP Phosphodiesterases
Animals
Cyclic Nucleotide Phosphodiesterases, Type 5
Female
Labor, Obstetric / metabolism*
Myometrium / enzymology*
Phosphodiesterase Inhibitors / pharmacology
Phosphoric Diester Hydrolases / metabolism*
Piperazines / pharmacology
Pregnancy
Pregnancy, Animal / metabolism*
Purines
Rats
Rats, Sprague-Dawley
Sulfones
Uterine Contraction / drug effects
Chemical
Reg. No./Substance:
0/Phosphodiesterase Inhibitors; 0/Piperazines; 0/Purines; 0/Sulfones; 139755-83-2/sildenafil; EC 3.1.4.-/Phosphoric Diester Hydrolases; EC 3.1.4.35/3',5'-Cyclic-GMP Phosphodiesterases; EC 3.1.4.35/Cyclic Nucleotide Phosphodiesterases, Type 5; EC 3.1.4.35/Pde5a protein, rat
Comments/Corrections
Comment In:
Am J Obstet Gynecol. 2006 Jul;195(1):184-5   [PMID:  16813753 ]

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