Myometrial Electrical Activity and Plasma Concentrations of Progesterone, Estrogens and Oxytocin during Late Pregnancy and Parturition in the Miniature Pig

Taverne, M.A.M.; Naaktgeboren, C.; Elsaesser, Folkmar; Forsling, Mary L.; Weyden, G. C. van der; Ellendorff, Franz; Smidt, Diedrich

doi:10.1095/biolreprod21.5.1125

Cited by 89 publications

(41 citation statements)

References 17 publications

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“…As soon as this segment also contracts the piglet will be enclosed by two isotonically contracted uterine parts. When one of the most caudally positioned fetuses has approached the pelvic region (which seems to occur by chance from one of the two horns according to Dziuk and Harmon (1969) and Taverne et al (1977)), its presence may initiate there a cervicotubally directed contraction. This contraction would prevent a slip-back of this fetus into the uterine horn and would cause a transport of the other fetuses in a cervicotubal direction.…”

Section: Resultsmentioning

confidence: 99%

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Myometrial activity and expulsion of fetuses

Taverne

Naaktgeboren

Weyden

1979

Animal Reproduction Science

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Chronic implantation of extracellular electrodes on successive uterine segments of pregnant miniature sows and marking of their fetuses were performed in order to relate characteristics of uterine electrical activity during delivery with the sequence of expulsion of piglets.The electromyographs during parturition were characterized by synchronic and well propagated phases of activity that could first appear at any of the four electrodes; however, initiation occurred most frequently at the electrodes on the two extreme ends of a horn. Analysis of the relative occurrence of tubocervitally and cervicotubally propagated activity phases indicated that the latter were present, and even could dominate, before and during expulsion of the piglets. The mean duration of the activity phases decreased and their mean propagation-time along the horn increased after emptying of the horn. However, before as well as after completion of delivery, a wide range in propagation-time of even two successive activity phases was measured.It is concluded that a decrease in uterine volumeis responsible for the rather abrupt changes of the characteristics of myometrial activity upon delivery of the piglets from a horn. Possible explanations for the wide range of the propagation-times are discussed and it is suggested that the cervicotubally directed contractions prevents untimely interruption of the fetal-placentalmaternal connections of the piglets that are not yet due to be expelled.

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Section: Resultsmentioning

confidence: 99%

“…Fetuses of one or both uterine horns were marked individually with a radiopaque substance by transuterine, intramuscular injections. Surgical details have already been published (Taverne et al, 1977).…”

Section: Methodsmentioning

confidence: 99%

Myometrial activity and expulsion of fetuses

Taverne

Naaktgeboren

Weyden

1979

Animal Reproduction Science

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“…In addition, compared to average plasma lactate values of 7.2-9.6 mmol/L reported in highly asphyxiated liveborn piglets [2,3], the average lactate value of 6.5 mmol/L observed at 10 min of life in the SV clamped piglets in this study is slightly lower. In our model of UCC, the additional effects of successive uterine contractions that are present during the expulsive stage of farrowing [31] are lacking, as the sows were not yet in partu during the surgical procedure. This latter finding was confirmed by the high plasma progesterone concentrations in blood samples collected from each sow at the day of the caesarean section (data not shown).…”

Section: Discussionmentioning

confidence: 99%

Umbilical cord clamping in term piglets: A useful model to study perinatal asphyxia?

et al. 2008

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Perinatal asphyxia results in tissue and cellular changes during the reperfusion period and clinical signs like perinatal mortality and decreased vitality at birth in newborn piglets. This study aimed to develop and validate a model of birth asphyxia, mimicking the evolvement of birth asphyxia in natural farrowings by conducting umbilical cord clamping (UCC) in term piglets during caesarean sections under general anaesthesia. In total 23 piglets were subjected to 5-8 min of UCC and 24 piglets served as controls. Acid-base balance values and heart rates measured before UCC remained fairly constant throughout the surgical procedure, indicating nearly identical starting conditions of piglets within and between litters. UCC resulted in a significant, mild, mixed respiratory-metabolic acidosis (pH 7.22, pCO 2 9.8 kPa, BE ecf 2 mmol/L, lactate 6.5 mmol/L; controls: pH 7.31, pCO 2 8.5 kPa, BE ecf 5 mmol/L, lactate 4 mmol/L) at 10 min after birth (defined as simultaneous cutting of the umbilical cord and removal of a plastic bag that had been placed over the head to avoid air intake). Heart rates were significantly decreased during UCC (range: 83-107 beats/min versus 128-134 beats/ min in controls). Rectal temperatures and changes in body weight until 72 h of life were not affected by UCC. Interestingly, four control and seven clamped piglets did not survive as no independent respiration could be attained. Birth weights and duration of UCC of these piglets did not differ significantly from those in surviving control and clamped piglets. In conclusion the mixed respiratory-metabolic acidosis arising in the surviving clamped piglets is not as severe as can be expected in highly asphyxiated, vaginally delivered newborn piglets. Repeatability of the model is compromised by considerable variation in the individual response to UCC. #

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“…One of the gilts was subject to all 3 treatments in consecutive cycles and 2 of the gilts were used in 2 treatments. Altogether, 4 gilts were evaluated in the saline and saline-oestrogen treatment (Taverne et a!, 1979b). First a bipolar electrode was placed 7 cm from the end of the cervix on the right uterine horn, then a second electrode was fitted 4 cm cranial to the first one (see Fig.…”

Section: Methodsmentioning

confidence: 99%

Spontaneous electromyographic activity throughout the cycle in the sow and its change by intrauterine oestrogen infusion during oestrus

Claus¹,

Ellendorff²,

Hoang-Vu³

1989

Reproduction

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Summary. Two experiments were carried out to monitor influences on the uterine electromyographic activity (EMG) 0\m=.\81;P < 0\m=.\01;n = 10) but not the frequency was observed. In Exp. 2 no significant change in contractile activity was found for the sal i ne\x=req-\ infused group and the controls over the 11-h recording periods. After infusion of saline with oestrogens the frequency increased significantly (P < 0\m=.\001) from 14\m=.\0\ m=+-\3\ m=. \ 1 contractions/h during the first hour up to a maximum of 31\m=.\2\m=+-\ 3\m=.\9/hat 2 h after infusion. Compared to the pretreatment period the frequency remained significantly elevated during the 3rd (28\m=.\7\ m=+-\2\m=.\3/h; P < 0\m=.\05) and 4th (20\m=.\2 \m=+-\ 3\m=.\9/h; P < 0\m=.\05) hour after infusion. Seminal oestrogens therefore stimulate uterine contractions at Day 0 and may play a physiological role for sperm transport.

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Myometrial Electrical Activity and Plasma Concentrations of Progesterone, Estrogens and Oxytocin during Late Pregnancy and Parturition in the Miniature Pig

Cited by 89 publications

References 17 publications

Myometrial activity and expulsion of fetuses

Myometrial activity and expulsion of fetuses

Umbilical cord clamping in term piglets: A useful model to study perinatal asphyxia?

Spontaneous electromyographic activity throughout the cycle in the sow and its change by intrauterine oestrogen infusion during oestrus

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