Myometrial activity and expulsion of fetuses

Taverne, M.A.M.; Naaktgeboren, C.; Weyden, G. C. van der

doi:10.1016/0378-4320(79)90041-1

Cited by 25 publications

(10 citation statements)

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“…The very steep increase in electrical activity, especially long spike bursts, in the uterine horn (Text-figs 3 and 5b) as compared to the body at 72 h pre partum suggests that electrical activity is propagated in the tubocervical direction, thus facilitating the expulsion of the fetus. This is consistent with the findings of Taverne et al (1979a) who reported that phases of propagated activity first appeared at the two ends of the horn in sows during parturition. It has not been possible to estimate the propagation velocity in the present study because several electrodes implanted successively along the uterine axis are required.…”

Section: Discussionsupporting

confidence: 94%

“…The electromyographic activity of the uterus during pregnancy and parturition when the uterus is subjected to the actions of several hormones has been studied by Bosc & Fevre (1974) and Naaktgeboren, Kroon & Schoof (1975). and Sakaguchi & Nakajima (1973) have characterized the electromyographic activity of the uterus during human labour and Bosc, du Mesnil du Buisson & Locatelli (1974), Bosc, Locatelli, Nicolle & du Mesnil du Buisson (1976) and Taverne, Naaktgeboren & van der Weyden (1979a) have studied the uterine changes in pigs at the time of parturition. The pattern of myoelectrical changes in the sheep uterus in the periparturient period was described by Prud'homme & Bosc (1977) and Krishnamurti, Kitts & Tompkins (1979).…”

Section: Introductionmentioning

confidence: 99%

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Myoelectrical changes in the uterus of the sheep around parturition

Krishnamurti¹,

Kitts²,

Kitts³

et al. 1982

Reproduction

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Myoelectrical activity in the uterus of late-pregnant sheep was recorded by the chronic implantation of bipolar electrodes in the myometrium. Three distinct patterns of electrical activity were recognizable: irregular trains of action potentials (greater than 120 sec), long spike bursts (7--120 sec), or short spike bursts (less than 7 sec) each exhibiting high (greater than 100 muV) or low (50--100 muV) amplitude. The duration of spike activity was expressed as the myoelectrical index (MI), i.e. the fraction of the hour during which a given category of activity is exhibited. The increase in the overall MI which represents daily average values regardless of the class of amplitude from 72 h pre partum up to parturition was significantly (P less than 0.05) more pronounced in the uterine horn than in the body of the uterus. During the last 6--7 days of gestation high-amplitude irregular trains and long spike bursts were significantly (P less than 0.05) more frequent than these activity patterns with low amplitude. Regardless of the amplitude, the incidence of irregular trains began to decline rapidly 48 h pre partum with an abrupt cessation following parturition. The frequency of long spike bursts increased 72 h pre partum to reach a maximum which coincided with parturition.

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Section: Discussionsupporting

confidence: 94%

Section: Introductionmentioning

confidence: 99%

Myoelectrical changes in the uterus of the sheep around parturition

Krishnamurti¹,

Kitts²,

Kitts³

et al. 1982

Reproduction

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“…In pregnant sows no coordinated uterine motility was observed until one day prae partum (42,43,51). At the onset of parturition contractions appear at regular intervals along the horn with both tubocervical and cervicotubal direction (44,51).…”

Section: Thilander Discussionmentioning

confidence: 99%

Adrenergic and Cholinergic Nerve Supply in the Porcine Myometrium and Cervix

Thilander

1989

Journal of Veterinary Medicine Series A

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Summary The distribution of adrenergic and acetylcholinesterase‐containing (cholinergic) nerves in the porcine myometrium and cervix was investigated neurohistochemically. In early and mid‐pregnancy the number of adrenergic nerves increased from the adtubal part of the horns to corpus uteri, being more abundant in non‐placental than in placental regions. No obvious difference in the distribution of cholinergic nerves was observed among the regions examined. The cervix was richest innervated by both types of nerves throughout gestation. The diameter of the adrenergic nerves decreased during pregnancy, while cholinergic nerves showed no such a decrease. In late pregnancy and at parturition the adrenergic innervation was richest at the adtubal part of the horns and in the cervix and scanty in the rest of the uterus. Adrenergic nerves were seen both in vascular and in non‐vascular smooth muscle, while cholinergic nerves were mostly associated to blood vessels. Zusammenfassung Adrenerge und cholinerge Innervierung des Myometriums und der Cervix beim Schwein. Eine histochemische Untersuchung während der Trächtigkeit und der Geburt Die Verteilung von adrenergen und Azetylcholinesterase‐haltigen (cholinergen) Nerven im Myometrium und in der Cervix des Schweines wurde neurohistochemisch untersucht. Während der frühen und mittleren Trächtigkeit nahm die Anzahl der adrenergen Nerven vom oviduktnahen Bereich der Uterushörner zum Corpus uteri hin zu, wobei sie in Placenta‐freien Arealen häufiger waren als in Arealen mit Placenta. Bezüglich der Verteilung der cholinergen Nerven ergaben sich zwischen verschiedenen Uterusabschnitten keine auffälligen Unterschiede. Während der gesamten Trächtigkeit war die Cervix mit beiden Typen von Nerven am ausgeprägtesten innerviert. Der Durchmesser der adrenergen Nerven verringerte sich während der Trächtigkeit. Für die cholinergen Nerven trifft dies nicht zu. Während der späten Trächtigkeit und zum Zeitpunkt der Geburt war die adrenerge Innervation im oviduktnahen Bereich der Uterushörner und in der Cervix am ausgeprägtesten, während sie im restlichen Uterus spärlich war. Adrenerge Nerven wurden in der vaskulären und nicht‐vaskulären glatten Muskulatur beobachtet, während die cholinergen Nerven meist mit Blutgefäßen vergesellschaftet waren.

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“…2006). During the expulsive stage, tubocervically and cervicotubally directed contractions move the piglets forwards and backwards within the uterine horns (Taverne et al. 1979b).…”

Section: Introductionmentioning

confidence: 99%

Parturition in Domestic Animals: Targets for Future Research

Taverne

Weijden

2008

Reprod Domestic Animals

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Contents Compared with other parts of the reproductive cycle, the parturition process of domestic animals has received relatively little attention from researchers during the last two decades. Yet, interventions during parturition, either by the owner or the veterinarian, are frequently judged necessary and perinatal losses in most of the domestic species are (still) rather high. The present paper focuses on the birth process in three domestic species, the dog, pig and cow, mainly because most of the experimental and research work of the authors themselves was dealing with these three species. Against the background of specific clinical problems, breeding circumstances and economic performance, selected topics and questions are addressed to identify areas for future research. These are, among others, related to the mechanisms that trigger the birth process (are the foetuses involved in the dog and sow?), the role of hormones and cytokines during ripening of the cervix (activation and/or de-activation of specific matrix metallo-proteinases and their local inhibitors), the functional significance of fetal body movements to prepare the foetus for expulsion, and the exact time course of events involved in the transportation of an individual foetus from its intrauterine location, via the pelvic canal, to the outside world. Research on some of these topics, such as the ripening of the cervix in cows, might also contribute to resolve clinical problems in human obstetrics.

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Myometrial activity and expulsion of fetuses

Cited by 25 publications

References 19 publications

Myoelectrical changes in the uterus of the sheep around parturition

Myoelectrical changes in the uterus of the sheep around parturition

Adrenergic and Cholinergic Nerve Supply in the Porcine Myometrium and Cervix

Parturition in Domestic Animals: Targets for Future Research

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