Fintl C, Hudson N P H, Handel I, Pearson G T
Norwegian University of Life Sciences, Faculty of Veterinary Medicine and Biosciences, Oslo, Norway.
Royal (Dick) School of Veterinary Studies and Roslin Institute, University of Edinburgh, Roslin, Midlothian, UK.
Equine Vet J. 2016 Mar;48(2):218-23. doi: 10.1111/evj.12401. Epub 2015 Mar 4.
Slow waves are rhythmic pacemaker currents generated by the gastrointestinal pacemaker cells, the interstitial cells of Cajal, and represent the rate-limiting step for small intestinal smooth muscle contractions. Therefore, factors that affect slow wave activity may also influence contractile activity. It is not known how temperature changes may influence slow wave activity in the horse. This could be of relevance during colic surgery if cooling of exposed intestine resulted in reduced slow wave activity potentially exacerbating post operative ileus.
To evaluate the effect of temperature changes on in vitro slow wave activity of normal equine ileum using intracellular recording techniques.
In vitro experimental study.
A segment of ileum was collected immediately following euthanasia from 9 horses for reasons unrelated to the gastrointestinal tract. Intracellular recordings of membrane potentials were made from individual smooth muscle cells. The temperature of the tissue bath was altered during the course of each experiment across a range of 27-41°C. All data were recorded and stored using a computer-interfaced acquisition system. A software package was used to analyse slow wave frequency, duration, amplitude and resting membrane potential.
In all 9 horses, slow wave frequency was highly temperature sensitive and approximately linearly related to the temperature over the range studied, increasing by 0.5 cycles/min for each 1°C increase in temperature (P<0.001). The initial slow wave frequency resumed when the temperature was returned to 37°C. The recovery time appeared to be directly related to the duration for which the temperature had been changed.
Slow wave frequency in the equine ileum is highly temperature sensitive. As post operative ileus is a major cause of morbidity and mortality in the horse, the negative effect of lower temperatures on slow waves, and therefore contractile activity, should be considered.
慢波是由胃肠道起搏细胞，即 Cajal 间质细胞产生的节律性起搏电流，代表小肠平滑肌收缩的限速步骤。因此，影响慢波活动的因素也可能影响收缩活动。目前尚不清楚温度变化如何影响马的慢波活动。如果在结肠手术中暴露的肠管冷却导致慢波活动降低，可能会加重术后肠梗阻，这一点可能具有重要意义。
使用细胞内记录技术评估温度变化对正常马回肠体外慢波活动的影响。
体外实验研究。
从 9 匹马身上采集一段回肠，这些马因与胃肠道无关的原因实施安乐死后立即进行采集。从单个平滑肌细胞进行膜电位的细胞内记录。在每个实验过程中，将组织浴的温度在 27 - 41°C 范围内改变。所有数据使用计算机接口采集系统进行记录和存储。使用软件包分析慢波频率、持续时间、幅度和静息膜电位。
在所有 9 匹马中，慢波频率对温度高度敏感，在所研究的温度范围内与温度大致呈线性关系，温度每升高 1°C，慢波频率增加 0.5 次/分钟（P<0.001）。当温度恢复到 37°C 时，初始慢波频率恢复。恢复时间似乎与温度改变的持续时间直接相关。
马回肠的慢波频率对温度高度敏感。由于术后肠梗阻是马发病和死亡的主要原因，应考虑低温对慢波以及因此对收缩活动的负面影响。
