Influence of environmental disturbances on uterine motility during pregnancy and parturition in rabbit and sheep

Bontekoe, E. H. M.; Blacquiere, J.F.; Naaktgeboren, C.; Dieleman, S.J.; Willems, P.P.M.

doi:10.1016/0376-6357(77)90039-0

Cited by 43 publications

(15 citation statements)

References 13 publications

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“…The transient inhibition clearly observed in one ewe at the time of mating was compatible with the reported effects of stress (Bontekoë, Blacquière, Naaktgeboren, Dieleman & Willems, 1977). Conversely, the absence of significant motility changes in 5 out of the 6 ewes disagrees with the findings of Lehrer, Schindler, Brown & Fischler (1978/79) who noted a significant increase, after mating, in both amplitude and frequency of pressure cycles, as recorded by means of intraluminal pressure-sensitive telemetrie transducers.…”

Section: Discussionsupporting

confidence: 41%

Pattern of electrical activity of the ovine uterus and cervix from mating to parturition

Garcia‐Villar¹,

Toutain²,

Ruckebusch³

1984

Reproduction

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The electrical activity of the uterus, greater curvature and lesser curvature, and of the cervix were recorded throughout several oestrous cycles, matings and the entire course of pregnancy in a set of ewes. In cyclic ewes, all electrode sites were active during the periovulatory period, but during the luteal phase only the cervix and lesser curvature continued to present regular activity, i.e. episodes of 6-8 min duration. Matings failed to disrupt the oestrous activity pattern in 5 out of 6 ewes. During the subsequent pregnancy in 4 ewes, activity, when present, consisted of the cyclic occurrence of regular activity episodes in the gravid horn(s) (greater curvature) and in the cervix (and lesser curvature in 1 ewe). Three phases were recognized on the basis of the activity of the greater curvature of the gravid horn(s). The first phase corresponded to quiescence of the horn from Day 5 (Day 0 = mating) to about Day 41. The second phase was marked by the sudden onset of regular activity of the uterus; frequency rapidly increased and maximal values were reached around Day 49, after which frequency progressively decreased until around Day 66. The third phase was characterized by a steady state in genital tract activity until the peripartum period. The cervix and lesser curvature activity followed an almost similar development of regular activity episodes with only slight time differences.

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Section: Discussionsupporting

confidence: 41%

Pattern of electrical activity of the ovine uterus and cervix from mating to parturition

Garcia‐Villar¹,

Toutain²,

Ruckebusch³

1984

Reproduction

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“…The present study shows the nearly synchronous appearance of regular activity in the cervix and the uterus. Such a pattern of periodic activity has been described for the uterus of the pregnant ewe by many authors using different terminology such as "train of action potentials" (Krishnarmurti, Kitts & Tompkins, 1979); "bursts" (Harding et ai, 1982); and "periods or bursts of activity" (Bontekoë, Blacquiere, Naakteboren, Dieleman & Willems, 1977). No preferential spread of activation between the uterus and cervix has been demonstrated, in agreement with Harding et al (1982) who have shown that activity appears synchronously at several sites in the uterus, suggesting humoral control or diffuse stimulation by a nerve network.…”

Section: Discussionmentioning

confidence: 97%

Electrical and mechanical activity of the cervix in the ewe during pregnancy and parturition

Toutain¹,

Garcia‐Villar²,

Hanzen

et al. 1983

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Myoelectrical and mechanical activities of the uterine cervix and horns of ewes fitted with electrodes and strain gauges were measured from the 30th day before until the 3rd day after parturition. During pregnancy, cervical electromyograms presented regular episodes of strong activity of a mean duration of 7 min, termed regular spiking activity, occurring at about 50-min intervals. Between two episodes, isolated or low frequency spikes occurred randomly and constituted the irregular spiking activity. The alternation of irregular and regular spiking activities was called the myoelectrical complex of the cervix. Clear relationships were noticed between electrical and mechanical events. On the pregnant uterine horn (singleton pregnancy) or on both horns (twin pregnancy), a myoelectrical complex pattern similar to that of the cervix was recorded. Regular spiking activity on the cervix and pregnant horn(s) occurred mainly simultaneously.No significant evolution of the myoelectrical complex pattern was noted throughout the last month of pregnancy until 2\p=n-\3 days before parturition. The activity pattern was then modified according to three characteristic phases: (1) a phase of relative inhibition of the cervix and pregnant horn(s) 48 h before lambing and lasting about 17 h; (2) a phase of increasing activity occurring thereafter over the whole genital tract with an average duration of 31 h; and (3) a phase of continuous activity of the cervix and uterus for 0\ m=. \ 4\ p=n-\ 3\ m=. \ 8h which accomplished the expulsion of the lamb.It is concluded that during the last month of pregnancy the cervix is active and that its activity arises from a basic ultradian rhythm involving the entire genital tract. Furthermore, although our results do not offer an explanation for the preparturient increase of cervical compliance described by others, they definitely excluded cervical muscular inhibition during the last 24 h of pregnancy and at the time of cervical dilatation.

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“…Given that does could produce sufficient OT for postpartum nursing, it seems that stimuli signaling parturition and stimulating the necessary peripheral release of OT were either lacking or blocked rather than that the hypothalamus was not able to produce OT. Mechanisms enabling the inhibition of birth signals certainly exist as demonstrated by the well-known ability of mammals to temporarily delay parturition if environmental conditions are unfavorable [23].…”

Section: Discussionmentioning

confidence: 99%

Parturition in the Rabbit is Compromised by Daytime Nursing: The Role of Oxytocin1

Hudson

Müller

Kennedy

1995

Biology of Reproduction

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Rabbits nurse briefly only once each night and are frequently both pregnant and lactating. To investigate the influence of the daily timing of nursing on parturition, does (n = 10 per group) were remated after giving birth and were allowed to nurse under one of three schedules: group 1 every 24 h in the light, group 2 every 24 h in the dark, and group 3 at any time. Whereas does from groups 2 and 3 nursed and gave birth normally, does of group 1, forced to nurse out of phase with the normal schedule, showed disturbed nursing behavior and prolonged gestation followed by many stillbirths. In a second experiment, pregnant does (n = 10 per group) were treated daily either with oxytocin (OT) in the light (group 4), with OT in the dark (group 5), or with progesterone (P; group 6) or saline (group 7) in the light. All does gave birth normally except those of group 4, which responded similarly to group 1 does. These findings demonstrate that in the rabbit, parturition may be seriously compromised if does nurse out of phase with the normal schedule and suggest that a shift in the daily timing of OT release may underlie this.

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Influence of environmental disturbances on uterine motility during pregnancy and parturition in rabbit and sheep

Cited by 43 publications

References 13 publications

Pattern of electrical activity of the ovine uterus and cervix from mating to parturition

Pattern of electrical activity of the ovine uterus and cervix from mating to parturition

Electrical and mechanical activity of the cervix in the ewe during pregnancy and parturition

Parturition in the Rabbit is Compromised by Daytime Nursing: The Role of Oxytocin1

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