title: Comparison of the porcine uterine smooth muscle contractility on days 12-14 of the estrous cycle and pregnancy.
abstract: BACKGROUND
  Uterine contractile activity is very important for many reproductive functions including embryo transport, implantation, gestation and parturition. Abnormal contractility leads to implantation failure, spontaneous miscarriage, preterm birth and many other disorders. The objective of the present study was to assess the effects of acetylcholine (ACh), noradrenaline (NA), oxytocin (OT) and prostaglandins F2α (PGF2α) and E2 (PGE2) on the contraction of uterine strips collected from the horns of cyclic gilts (12-14 days of the estrous cycle-group I) and from pregnant (12-14 days after first insemination gilts in which one of the uterine horn was gravid (group IIa) and the second one was non-gravid (group IIb). Uterine strips consisting of the endometrium with the myometrium and myometrium alone were examined.
  
  
  RESULTS
  ACh increased the tension in all groups as compared to the pretreatment period, and the increase was the highest in group IIb; the amplitude decreased in all groups, and the frequency increased mainly in groups I and IIa. NA did not affect the tension in any group, but decreased the amplitude and frequency in group IIb as compared to groups I and IIa. OT caused the highest increase in the tension in group IIb, a decrease in the amplitude and an increase in the frequency of contractions as compared to the pretreatment period. PGF2α induced the highest increase in the tension and amplitude in group IIb, with a decline in the frequency in this group. PGE2 increased the tension and frequency only in group IIb, and caused the greatest eduction in the amplitude in this group.
  
  
  CONCLUSIONS
  These results indicate that contractility of the porcine smooth muscle collected from uterine horns with embryos was different from those obtained from the uterine horns without embryos and the horns of cyclic gilts.
authors.affiliation: Department of Pharmacology and Toxicology, Faculty of Veterinary Medicine, University of Warmia and Mazury, Oczapowskiego Street 13, 10-718, Olsztyn, Poland. mark@uwm.edu.pl.
authors.forename: Włodzimierz
authors.initials: W
authors.lastname: Markiewicz
authors.affiliation: Institute of Animal Reproduction and Food Research, Polish Academy of Sciences, Bydgoska Street 7, 10-243, Olsztyn, Poland.
authors.forename: Marek
authors.initials: M
authors.lastname: Bogacki
authors.affiliation: Institute of Animal Reproduction and Food Research, Polish Academy of Sciences, Bydgoska Street 7, 10-243, Olsztyn, Poland.
authors.forename: Michał
authors.initials: M
authors.lastname: Blitek
authors.affiliation: Department of Pharmacology and Toxicology, Faculty of Veterinary Medicine, University of Warmia and Mazury, Oczapowskiego Street 13, 10-718, Olsztyn, Poland.
authors.forename: Jerzy Jan
authors.initials: JJ
authors.lastname: Jaroszewski
mesh_terms: D000818:Animals; D001679:Biogenic Amines / Q000378:metabolism; D030762:Estrous Cycle; D005260:Female; D009119:Muscle Contraction; D009215:Myometrium / Q000502:physiology*; D010121:Oxytocin / Q000378:metabolism; D011247:Pregnancy; D011453:Prostaglandins / Q000378:metabolism; D034421:Sus scrofa / Q000502:physiology*
chemical_list: D001679:Biogenic Amines; D011453:Prostaglandins; D010121:Oxytocin
keywords: Early pregnancy; Embryos; Gilts; Uterine contractility