title: In vivo measurement of intrauterine pressure by telemetry: a new approach for studying parturition in mouse models.
abstract: Transgenic and knockout mouse models have proven useful in the study of genes necessary for parturition-including genes that affect the timing and/or progression of labor contractions. However, taking full advantage of these models will require a detailed characterization of the contractile patterns in the mouse uterus. Currently the best methodology for this has been measurement of isometric tension in isolated muscle strips in vitro. However, this methodology does not provide a real-time measure of changes in uterine pressure over the course of pregnancy. Recent advances have opened the possibility of using radiotelemetric devices to more accurately and comprehensively study intrauterine pressure in vivo. We tested the effectiveness of this technology in the mouse, in both wild-type (WT) mice and a mouse model of defective parturition (SK3 channel-overexpressing mice), after surgical implant of telemetry transmitters into the uterine horn. Continuous recordings from day 18 of pregnancy through delivery revealed that WT mice typically deliver during the 12-h dark cycle after 19.5 days postcoitum. In these mice, intrauterine pressure gradually increases during this cycle, to threefold greater than that measured during the 12-h cycle before delivery. SK3-overexpressing mice, by contrast, exhibited lower intrauterine pressure over the same period. These results are consistent with the outcome of previous in vitro studies, and they indicate that telemetry is an accurate method for measuring uterine contraction, and hence parturition, in mice. The use of this technology will lead to important novel insights into changes in intrauterine pressure during the course of pregnancy.
authors.affiliation: Department of Molecular Physiology and Biophysics, University of Iowa Carver College of Medicine, Iowa City, IA 52242, USA.
authors.forename: Stephanie L
authors.initials: SL
authors.lastname: Pierce
authors.forename: William
authors.initials: W
authors.lastname: Kutschke
authors.forename: Rafael
authors.initials: R
authors.lastname: Cabeza
authors.forename: Sarah K
authors.initials: SK
authors.lastname: England
mesh_terms: D000818:Animals; D005260:Female; D051379:Mice; D023421:Models, Animal; D036801:Parturition / Q000502:physiology*; D011247:Pregnancy; D051640:Small-Conductance Calcium-Activated Potassium Channels / Q000235:genetics / Q000378:metabolism; D013686:Telemetry / Q000379:methods*; D014590:Uterine Contraction / Q000502:physiology*
chemical_list: C496900:Kcnn3 protein, mouse; D051640:Small-Conductance Calcium-Activated Potassium Channels
references.citation: Obstet Gynecol. 1966 Mar;27(3):371-7
references.pmid: 5909557
references.citation: Biol Reprod. 1993 Jan;48(1):33-9
references.pmid: 8418915
references.citation: Pediatr Res. 2008 Dec;64(6):581-9
references.pmid: 18679156
references.citation: Am J Physiol Regul Integr Comp Physiol. 2009 Sep;297(3):R525-45
references.pmid: 19515978
references.citation: N Engl J Med. 2007 Aug 2;357(5):477-87
references.pmid: 17671256
references.citation: Biol Reprod. 2009 Dec;81(6):1226-32
references.pmid: 19684330
references.citation: J Appl Physiol (1985). 2000 May;88(5):1537-44
references.pmid: 10797109
references.citation: Semin Reprod Med. 2007 Jan;25(1):40-51
references.pmid: 17205422
references.citation: Science. 2000 Sep 15;289(5486):1942-6
references.pmid: 10988076
references.citation: J Perinat Med. 2009;37(4):313-9
references.pmid: 19292588
references.citation: Am J Obstet Gynecol. 2008 Feb;198(2):235.e1-4
references.pmid: 18226633
references.citation: Biol Reprod. 2008 Jun;78(6):1058-63
references.pmid: 18305226
references.citation: Pediatrics. 2006 Oct;118(4):1566-73
references.pmid: 17015548
references.citation: Ann Med. 2008;40(3):167-95
references.pmid: 18382883