An In vitro Study on Spontaneous Cervical Contractility in the Cow During Oestrus and Diestrus

Abstract

Cervical smooth muscle specimens were collected from slaughtered cows in oestrus and diestrus. Longitudinal and circular specimens were mounted in organ baths and after equilibration time and 2 g pre-load, their physiologic isometric contractility was recorded for 2.5 h. Area under the curve (AUC), maximal amplitude (Amax), mean amplitude (Amen) and minimal amplitude (Amin) were studied. Differences between cycle phases, between muscle layers and over the recorded time periods were statistically evaluated using linear mixed-effect models. In the cow, physiologic contractility of the cervix decreased significantly over time for all variables evaluated (time as covariate on a continuous scale). Furthermore, for Amax, there was a tendency for an influence of muscle layer (longitudinal > circular). Contractility was not influenced by cycle phases.

Smooth Muscle Cells of the Bovine Cervical Stroma may have a Secretory, rather than a Contractile Function during Parturition

“…This would correspond with our previous findings in cows that no EMG activity could be detected in this tissue during calving (van Engelen et al. 2007), even though contractions of the cervical stroma of non‐pregnant cows have been observed in vitro spontaneously (Hirsbrunner et al. 2003) and in response to oxytocin (van Engelen et al.…”

“…Cervical muscular contractions have been reported in human, rat, sheep and cow cervices, both in vitro (Hollingsworth and Isherwood 1978;Bryman et al 1986;Hirsbrunner et al 2003) and in vivo (Toutain et al 1983;Pajntar and Verdenik 1995;van Engelen et al 2007). Yet, the physiological relevance of cervical smooth muscle contractility has been questioned for the rabbit, rat and human because of the low density of smooth muscle cells and on the basis of contraction studies (Conrad and Hoover 1982;Petersen et al 1991;Vedernikov et al 2000).…”

“…Cervical muscular contractions have been reported in human, rat, sheep and cow cervices, both in vitro (Hollingsworth and Isherwood 1978; Bryman et al. 1986; Hirsbrunner et al. 2003) and in vivo (Toutain et al.…”

Estrous cycle‐dependent differences in responsiveness to prostaglandins and contractile agents in sheep (Ovis aries) cervical smooth muscle

“…In relation to the studies with ACh, we observed no significant differences between the estrous cycle phases for maximum effect amplitudes and EC 50 values produced in both cervical muscle layers. The few in vivo studies performed in sheep (Garcia-Villar et al, 1982a) and bovine (Hirsbrunner et al, 2003) cervical muscle have found no influence of estrous cycle phase in spontaneous motility. However in rat, results in myometrium indicated an increase in cholinergic control during the follicular phase (estrus), with a higher sensitivity to ACh and without changes in nerve density (Houdeau et al, 2003), compared with the luteal phase (diestrus).…”

“…The few in vivo studies performed in sheep (Garcia‐Villar et al. , 1982a) and bovine (Hirsbrunner et al. , 2003) cervical muscle have found no influence of estrous cycle phase in spontaneous motility.…”