The effect of oxytocin on contractility of the equine oesophagus: a potential treatment for oesophageal obstruction

Abstract

Summary This study was performed to determine the effect of administration of i.v. oxytocin on the contractility of the musculature associated with the equine oesophagus. Nine clinically normal horses were fitted with a nasogastric tube modified with inflatable latex cuffs. These cuffs were connected to piezoelectric pressure recording devices. Oxytocin in 3 different doses or saline controls were administered i.v. in a randomised block pattern. Systolic blood pressure, ECG, heart rate and nasogastric tube cuff pressures were then measured for 60 min. Administration of oxytocin i.v. at 0.11 and 0.22 iu/kg bwt, resulted in a short‐term statistically significant relaxation of the musculature of the equine oesophagus. When oxytocin was administered at 0.11, 0.22 and 0.44 iu/kg bwt, no clinically significant cardiovascular changes were seen. In approximately 5% of the oxytocin administrations, signs of mild short‐term abdominal discomfort were observed. In clinical cases of noncomplicated oesophageal obstruction, it is suggested that reduction in tone of oesophageal musculature may result in passage of oesophageal obstructions with reduced risk of oesophageal injury when compared to other traditional treatments.

Congenital oesophageal stricture in anArabian filly treated by balloon dilation

“…In the study by Meyer et al . () several doses of i.v. oxytocin were shown to cause intramural pressure reduction due to relaxation of the striated muscle located in the proximal two‐thirds of the oesophagus.…”

Clinical Features and Prognostic Variables in 109 Horses with Esophageal Obstruction (1992-2009)

“…Oxytocin (0.11-0.22 IU/kg IV) has been reported to induce transient relaxation of esophageal musculature in healthy horses and resolution of choke in 8 of 10 horses. 13 However, other investigators have not been able to corroborate these findings using manometric evaluations of the esophagus in the absence of balloon distention of the esophagus.…”

Milk regurgitation caused by oesophageal stricture in foals

“…However, other studies have demonstrated some effect on contractility as measured by piezoelectric pressure transducer (Meyer et al . ). In this study, the placement of the transducer induced internal pressure on the oesophagus and then measured the oesophageal resistance to that pressure after the administration of oxytocin.…”