Aberrations in uterine contractile patterns in mares with delayed uterine clearance after administration of detomidine and oxytocin.
Abstract: An experiment was conducted to determine whether the uterotonic effects of oxytocin, a drug used to treat mares that have a delay in uterine clearance were affected by the sedative detomidine (an alpha2-agonist), a drug used to treat fractious mares. An additional objective was to identify propagation patterns of uterine contractions and determine whether these patterns differed between normal mares and mares with delayed uterine clearance (DUC). Intrauterine pressure was measured in five reproductively normal mares and four mares with DUC during estrus using an 8-F Milar catheter with two discrete pressure sensors. Mares received one of three treatments in random order: detomidine (0.001 mg/kg; i.v.); detomidine followed in 10 min by oxytocin (10 IU; i.v.); and saline (0.9% NaCl 0.5 ml; i.v.) followed in 10 min by oxytocin. All treatments induced waves of contractions; however, only three mares with DUC exhibited contractions after administration of detomidine. Normal mares experienced more uterine contractions (P < 0.01) that tended to last longer (P < 0.06), and were of greater intensity (P < 0.04) than mares with delayed clearance. Administration of detomidine before oxytocin increased the number of contractions (P < 0.02) and increased the maximum intrauterine pressure in the uterine horn (P < 0.05) in normal mares as compared to response after administration of saline and oxytocin. Detomidine had no effect in mares with delayed clearance. All mares had more propagating than non-propagating uterine contractions (74 +/- 8 versus 25 +/- 8%, respectively). Normal mares exhibited a normal propagation pattern more frequently (P < 0.0001) than mares with DUC. Simultaneous (P < 0.05) and inverted (P < 0.03) contractions occurred more frequently in mares with DUC. Administration of detomidine increased the number (P < 0.01), and tended to increase the percentage (P < 0.07) of normal propagating uterine contractions in normal mares, but did not affect propagation patterns in mares with DUC. In conclusion, detomidine augmented the uterotonic effect of oxytocin in normal mares but not in mares with DUC. Data suggest that mares with DUC have a defect in myoelectrical signaling and a decrease in the contractile strength of the uterine muscle.
Publication Date: 2002-09-06 PubMed ID: 12212889DOI: 10.1016/s0093-691x(02)00847-6Google Scholar: Lookup
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- Journal Article
- Research Support
- Non-U.S. Gov't
Summary
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This research explored the effectiveness of two drugs, oxytocin and detomidine, in treating delayed uterine clearance (DUC) in mares. The results suggest that while both drugs induced uterine contractions, mares with DUC responded less than normal mares, implicating a potential defect in the myoelectrical signaling and muscular strength of the uterus in these cases.
Objective and Methodology
- The research aimed to understand the impact of oxytocin and detomidine on the contractile patterns of the uterine muscle, specifically in mares suffering from delayed uterine clearance (DUC). Comparisons were made between this group and reproductively normal mares to identify any potential differences.
- A sample of nine mares, five normal and four with DUC, had their intrauterine pressure measured during estrus. This procedure was accomplished through the use of an 8-F Milar catheter equipped with two discrete pressure sensors.
- The mares were subjected to one of three treatments at random: administration of detomidine alone, detomidine followed by oxytocin, or lastly, saline followed by oxytocin.
Findings
- All treatments resulted in waves of contractions. However, only three out of the four mares with DUC showed signs of contraction after being given detomidine.
- Normal mares experienced more contractions, of a longer duration and higher intensity, compared to mares with DUC.
- The use of detomidine prior to oxytocin led to an increase in contractions, as well as a spike in intrauterine pressure in normal mares. This was not the case if saline was used before injecting oxytocin.
- Normal mares demonstrated a normal pattern of contraction propagation more frequently compared to mares with DUC, which exhibited simultaneous and inverted contractions more commonly.
- Detomidine increased the number, and possibly the percentage, of normal propagating uterine contractions in normal mares but did not affect propagation patterns in mares with DUC.
Conclusion
- Detomidine increased the uterotonic effects induced by oxytocin in normal mares but not in those suffering from DUC.
- The lessened contractive response observed in mares with DUC indicated a defect in myoelectrical signaling and reduced strength of uterine muscle contractions.
Cite This Article
APA
von Reitzenstein M, Callahan MA, Hansen PJ, LeBlanc MM.
(2002).
Aberrations in uterine contractile patterns in mares with delayed uterine clearance after administration of detomidine and oxytocin.
Theriogenology, 58(5), 887-898.
https://doi.org/10.1016/s0093-691x(02)00847-6 Publication
Researcher Affiliations
- Department of Large Animal Clinical Sciences, University of Florida, Gainesville 32610-0136, USA.
MeSH Terms
- Adrenergic alpha-Agonists / administration & dosage
- Animals
- Female
- Horse Diseases / physiopathology
- Horses
- Imidazoles / administration & dosage
- Oxytocin / administration & dosage
- Pregnancy
- Pressure
- Uterine Contraction / drug effects
- Uterine Diseases / physiopathology
- Uterine Diseases / veterinary
Citations
This article has been cited 1 times.- Piotrowska-Tomala KK, Szóstek-Mioduchowska AZ, Drzewiecka EM, Jonczyk AW, Wójtowicz A, Wrobel MH, Ferreira-Dias G, Skarzynski DJ. Prostaglandin pathways in equine myometrium regulations: endometrosis progression. Front Vet Sci 2024;11:1479508.
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