Institute of Biomedical Engineering, University of Toronto, Toronto, Ontario, Canada.
Edward S. Rogers Sr. Department of Electrical and Computer Engineering, University of Toronto, Toronto, Ontario, Canada.
Neurogastroenterol Motil. 2024 Jun;36(6):e14815. doi: 10.1111/nmo.14815. Epub 2024 May 12.
There has been recent clinical interest in the use of vagus nerve stimulation (VNS) for treating gastrointestinal disorders as an alternative to drugs or gastric electrical stimulation. However, effectiveness of burst stimulation has not been demonstrated. We investigated the ability of bursting and continuous VNS to influence gastric and pyloric activity under a range of stimulation parameters and gastric pressures. The goals of this study were to determine which parameters could optimally excite or inhibit gastric activity.
Data were collected from 21 Sprague-Dawley rats. Under urethane anesthesia, a rubber balloon was implanted into the stomach, connected to a pressure transducer and a saline infusion pump. A pressure catheter was inserted at the pyloric sphincter and a bipolar nerve cuff was implanted onto the left cervical vagus nerve. The balloon was filled to 15 cmHO. Stimulation trials were conducted in a consistent order; the protocol was then repeated at 25 and 35 cmHO. The nerve was then transected and stimulation repeated to investigate directionality of effects.
Bursting stimulation at the bradycardia threshold caused significant increases in gastric contraction amplitude with entrainment to the bursting frequency. Some continuous stimulation trials could also cause increased contractions but without frequency changes. Few significant changes were observed at the pylorus, except for frequency entrainment. These effects could not be uniquely attributed to afferent or efferent activity.
Our findings further elucidate the effects of different VNS parameters on the stomach and pylorus and provide a basis for future studies of bursting stimulation for gastric neuromodulation.
最近临床上有兴趣使用迷走神经刺激（VNS）治疗胃肠道疾病作为药物或胃电刺激的替代方法。然而，尚未证明爆发刺激的有效性。我们研究了爆发刺激和连续刺激在一系列刺激参数和胃压下影响胃和幽门活动的能力。本研究的目的是确定哪些参数可以最佳地激发或抑制胃活动。
从 21 只 Sprague-Dawley 大鼠中收集数据。在乌拉坦麻醉下，将橡胶气球植入胃中，与压力传感器和盐水输注泵相连。将压力导管插入幽门括约肌，并将双极神经袖带植入左侧颈迷走神经上。将气球充至 15cmHO。以一致的顺序进行刺激试验；然后在 25 和 35cmHO 重复该方案。然后切断神经并重复刺激以研究效应的方向性。
在心动过缓阈值下进行爆发刺激会导致胃收缩幅度显著增加，并与爆发频率同步。一些连续刺激试验也可能导致收缩增加，但频率没有变化。除了频率同步外，在幽门很少观察到明显的变化。这些影响不能仅归因于传入或传出活动。
我们的发现进一步阐明了不同 VNS 参数对胃和幽门的影响，并为未来胃神经调节的爆发刺激研究提供了基础。
