Fushimi Taiki, Fujii Yasuyuki, Koshino Hideaki, Inagawa Kodai, Saito Akiko, Koizumi Ryo, Shibata Masahiro, Osakabe Naomi
Functional Control Systems, Graduate School of Engineering and Science, Shibaura Institute of Technology, 307 Fukasaku, Minumaku, Saitama, 337-8570, Japan.
Department of Bioscience and Engineering, Shibaura Institute of Technology, 307 Fukasaku, Minumaku, Saitama, 337-8570, Japan.
Exp Anim. 2021 Aug 6;70(3):372-377. doi: 10.1538/expanim.20-0200. Epub 2021 Apr 12.
It is known that administering a gavage to rodents evokes a cardiac reflex, due to gastrointestinal stimulation. Consequently, it is difficult to evaluate changes in hemodynamics after a single oral dose of a pungent or astringent, which alters the circulation by increasing sympathetic activity. In the present study, we developed a method for administering a gavage without significantly affecting hemodynamics measurements. We marked a gastric tube at 10 cm from the tip, to mark the distance from the oral cavity to the stomach body of Wistar male rats. Rats were intubated under urethane anesthesia.After 10-15 min of stabilization, we measured the mean blood pressure (MBP), heart rate (HR), and blood flow (BF) in the cremaster arteriole under two different conditions; condition 1: a pointed gastric tube, room temperature distilled water, and injected at normal speed (approximately 3 ml/min); condition 2: a rounded gastric tube, 37°C distilled water, and injection at 1.0 ml/min. Under condition 1, we observed striking hemodynamic alterations, due to the somatic afferent reflex. In contrast, under condition 2, these hemodynamic changes were nearly eliminated. In addition, we could clearly detect hemodynamic changes in rats after a single gavage treatment of pungent (capsaicin) or astringent (cinnamtannin A2). We observed transient increases in the HR and MBP soon after treatment with capsaicin. Moreover, cremasteric BF was elevated with cinnamtannin A2. These results confirmed the utility of the gavage method developed in this study.
已知对啮齿动物进行灌胃会因胃肠道刺激引发心脏反射。因此，很难评估单次口服辛辣或收敛剂后的血流动力学变化，因为这类药物会通过增加交感神经活动来改变循环。在本研究中，我们开发了一种在不显著影响血流动力学测量的情况下进行灌胃的方法。我们在距胃管尖端10厘米处做标记，以标明从口腔到Wistar雄性大鼠胃体的距离。大鼠在氨基甲酸乙酯麻醉下进行插管。稳定10 - 15分钟后，我们在两种不同条件下测量提睾肌小动脉的平均血压（MBP）、心率（HR）和血流量（BF）；条件1：尖胃管、室温蒸馏水，以正常速度（约3毫升/分钟）注射；条件2：圆头胃管、37℃蒸馏水，以1.0毫升/分钟的速度注射。在条件1下，由于躯体传入反射，我们观察到明显的血流动力学改变。相比之下，在条件2下，这些血流动力学变化几乎被消除。此外，我们能够清楚地检测到大鼠在单次灌胃辛辣剂（辣椒素）或收敛剂（肉桂鞣质A2）后的血流动力学变化。在用辣椒素处理后，我们很快观察到心率和平均血压短暂升高。此外，肉桂鞣质A2使提睾肌血流量增加。这些结果证实了本研究中开发的灌胃方法的实用性。
