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Behavioral and Physiological Analyses of Parturition In Pregnant Rats: Insights Derived from Intrauterine TelemetryDuring labor and birth, fetuses are exposed to considerable physical stimulation associated with labor contractions and expulsion from the womb These forces are important for the neonates' adaptation to tile extrauterine environment. To further our understanding of the relationship between labor and postpartum outcome, we developed a novel method for measuring intrauterine pressure (IUP) in freely-moving, late pregnant and parturient rats that enables us to make precise, reliable measures of the forces experienced by rat fetuses during parturition. A small (1.25 x 4 cm) telemetric blood pressure sensor was fitted within a fluid-filled balloon, similar in size to a full term rat fetus. On Gestational day (G) 19 of the rats' 22/23 day pregnancy, each dam was anesthetized and a balloon/sensor unit surgically implanted within the uterus following removal of two fetuses. Comparisons were made between sensor-implanted dams (IMPL) and a control conditions: 1) LAP-R, laparotomy with two fetuses removed or 2) LAP-NR, laparotomy with no fetuses removed. IUP signals were sampled at 10s intervals from the IMPL dams during labor and birth. Dams in all three conditions were videorecorded enabling us to analyze the effect of the implant on behavioral expressions of parturition. Contraction frequency, duration, pup-to-pup birth intervals and pup-oriented activities of the dams measured from one hour prior to the first pup birth until the birth of the third pup were unaffected by the sensor implant. Intrauterine telemetry of freely-moving dams offers significant advantages over conventional hardwired IUP measurement techniques. These findings establish and validate intrauterine telemetry as a reliable, non-invasive technique for quantifying pressures associated with parturition.
Document ID
20030002370
Acquisition Source
Ames Research Center
Document Type
Preprint (Draft being sent to journal)
Authors
Villareal, J.
(San Jose State Univ. CA United States)
Mallery, E.
(Stanford Univ. Stanford, CA United States)
Lynch, A.
(Rhodes Coll. Memphis, TN United States)
Mills, N.
(California Univ. Davis, CA United States)
Baer, L.
(NASA Ames Research Center Moffett Field, CA United States)
Wade, C.
(NASA Ames Research Center Moffett Field, CA United States)
Ronca, A.
(NASA Ames Research Center Moffett Field, CA United States)
Dalton, Donnie
Date Acquired
August 21, 2013
Publication Date
January 1, 2002
Subject Category
Life Sciences (General)
Funding Number(s)
PROJECT: RTOP 121-10-40
CONTRACT_GRANT: NIMH-MH46485
PROJECT: RTOP 121-10-50
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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