Lidocaine decreases the xylazine-evoked contractility in pregnant cows

- We identified the effect of xylazine on bovine uteri in various gestational stage.
- We identified the effect of lidocaine on xylazine-evoked contractility.
- We showed that xylazine enhances contractility mostly at 30-60 days.
- We showed, that lidocaine decrease xylazine-evoked contractility in pregnant cows.

The objective of this in vitro study was to evaluate and compare the effects of xylazine on basal uterine contractility of bovine pregnant uterine strips and that of lidocaine on xylazine-sensitized bovine pregnant uterine strips, at different stages of pregnancy. Basal contractility was evaluated in an isolated organ bath and the functionality of the strips throughout the experiment was evaluated using a dose of carbachol (10− 5 M). Uterine motility, expressed with amplitude, frequency of contractions as well as the area under the curve, was recorded in different stages of pregnancy and data were collected at 15-min intervals (5-min before and 5-min after xylazine administration and 5-min after lidocaine addition on the plateau contraction induced by xylazine). Uterine motility increased in all the stages of pregnancy after xylazine addition and gradually decreased after treatment with lidocaine. These data suggest that lidocaine might decrease the tonic effect induced by xylazine on bovine pregnant uteri.