Evaluation of the effect of different sedative doses of dexmedetomidine on the intestinal motility in clinically healthy donkeys (Equus asinus)

Abstract

Aim Gastrointestinal effects of different doses of dexmedetomidine in donkeys are still unidentified. The current study aimed to evaluate the impact of different doses of dexmedetomidine on the motility of selected parts of the gastrointestinal tracts in donkeys using transabdominal ultrasonography. Materials and methods An experimental crossover study was conducted on 30 healthy donkeys of both sexes (15 males and 15 females; 160 ± 60 kg). With a two-week washout period, each donkey received an injection of either a normal saline solution or three different doses of dexmedetomidine (3, 5, and 7 μg/kg, respectively). All medications were administered intravenously in equal volumes. The contractility of selected intestinal segments (duodenum, jejunum, left colon, right colon, and cecum) was measured 3 min before administration (zero time) and at 15, 30, 45, 60, 90, and 120 minutes after administration. Results Small and large intestinal motility was within the normal ranges before IV injection of normal isotonic saline or dexmedetomidine at a dose of 3, 5, and 7 μg/kg. Two Way Repeated Measures ANOVA output of the data displayed a statistically significant the between time and treatments for the contractility of each of the duodenum (P = 0.0029), jejunum (P = 0.0033), left colon (P = 0.0073), right colon (P = 0.0035), and cecum (P = 0.0026), implying that the impact of treatment on the gastric motility varied among different time points. The simple main effect analysis revealed that the IV dexmedetomidine at 3, 5, and 7 μg/kg doses significantly inhibited (P ≤ 0.01) the bowel contractility compared to the administration of isotonic saline. Conclusion Dose-dependent inhibitory effect of dexmedetomidine on intestinal motility was reported in donkeys following intravenous administration. This inhibitory effect on intestinal motility should be considered in clinical practice.

Dexmedetomidine Has Differential Effects on the Contractility of Equine Jejunal Smooth Muscle Layers In Vitro

“…This study found increased in vitro contractility of the LSM with dexmedetomidine treatment, which conflicts with two in vivo studies that found decreased gut sounds following dexmedetomidine administration in horses [ 18 , 21 ]. This illustrates the fact that in vitro contractile activity does not necessarily translate to an increased motility in vivo.…”

“…Medetomidine and its active D-isomer dexmedetomidine are more selective α2 agonists that are not as commonly used in horses, yet are known produce effective and safe sedation [ 18 , 19 , 20 ]. These drugs have also been shown to affect intestinal function, with medetomidine decreasing intestinal circular smooth muscle contractility in vitro [ 16 ], and decreased borborygmia being documented the first hour after dexmedetomidine administration in horses and donkeys [ 18 , 21 ].…”

The Effect of Dexmedetomidine Sedation on Lower Gastrointestinal Motility in Children—Is It Suitable for Anorectal Manometry?

“…Additionally, there been studies in adult patients that have shown that DEX does impact upper esophageal sphincter function with pharyngeal swallowing and depressed the contractile function of the proximal esphagus with esophageal swallowing [25]. In animal studies, DEX has shown to have a dose-dependent effect on the inhibition of gastrointestinal motility (duodenum, jejunum, colon and cecum) in donkeys [26]. However, the effects on the lower gastrointestinal tract in humans suggest that DEX may have a positive effect on improving return of motility following abdominal surgery in adult patients [27].…”