Zena Lucas A, da Silva Glauber S F, Gargaglioni Luciane H, Bícego Kênia C
Department of Animal Morphology and Physiology, College of Agricultural and Veterinary Sciences, São Paulo State University, Jaboticabal, São Paulo 14884-900, Brazil
National Institute of Science and Technology in Comparative Physiology (INCT Fisiologia Comparada), Jaboticabal, São Paulo 14884-900, Brazil.
J Exp Biol. 2016 Nov 15;219(Pt 22):3605-3615. doi: 10.1242/jeb.144774. Epub 2016 Sep 15.
Anurans regulate short-term oscillations in blood pressure through changes in heart rate (f), vascular resistance and lymphatic f Lung ventilation in anurans is linked to blood volume homeostasis by facilitating lymph return to the cardiovascular system. We hypothesized that the arterial baroreflex modulates pulmonary ventilation in the cururu toad Rhinella schneideri, and that this relationship is temperature dependent. Pharmacologically induced hypotension (sodium nitroprusside) and hypertension (phenylephrine) increased ventilation (25°C: 248.7±25.7 ml kg min; 35°C: 351.5±50.2 ml kg min) and decreased ventilation (25°C: 9.0±6.6 ml kg min; 35°C: 50.7±15.6 ml kg min), respectively, relative to control values from Ringer solution injection (25°C: 78.1±17.0 ml kg min; 35°C: 137.7±15.5 ml kg min). The sensitivity of the ventilatory response to blood pressure changes was higher during hypotension than during hypertension [25°C: -97.6±17.1 versus -23.6±6.0 breaths min kPa; 35°C: -141.0±29.5 versus -28.7±6.4 breaths min kPa, respectively; negative values indicate an inverse relationship between blood pressure and ventilation (or breathing frequency), i.e. as blood pressure increases, ventilation decreases, and vice versa], while temperature had no effect on these sensitivities. Hyperoxia (30%; 25°C) diminished ventilation, but did not abolish the ventilatory response to hypotension, indicating a response independent of peripheral chemoreceptors. Although there are previous data showing increased f baroreflex sensitivity from 15 to 30°C in this species, further increases in temperature (35°C) diminished f baroreflex gain (40.5±5.62 versus 21.6±4.64% kPa). Therefore, besides an involvement of pulmonary ventilation in matching O delivery to demand at higher temperatures in anurans, it also plays a role in blood pressure regulation, independent of temperature, possibly owing to an interaction between baroreflex and respiratory areas in the brain, as previously suggested for mammals.
无尾两栖类动物通过心率（f）、血管阻力和淋巴系统的变化来调节血压的短期波动。无尾两栖类动物的肺通气通过促进淋巴回流至心血管系统，与血容量稳态相关。我们假设，动脉压力反射调节库鲁鲁蟾蜍（Rhinella schneideri）的肺通气，且这种关系依赖于温度。药理学诱导的低血压（硝普钠）和高血压（去氧肾上腺素）分别使通气增加（25℃：248.7±25.7 ml·kg·min；35℃：351.5±50.2 ml·kg·min）和减少（25℃：9.0±6.6 ml·kg·min；35℃：50.7±15.6 ml·kg·min），相对于注射林格液的对照值（25℃：78.1±17.0 ml·kg·min；35℃：137.7±15.5 ml·kg·min）。通气对血压变化的反应敏感性在低血压时高于高血压时[25℃：-97.6±17.1对-23.6±6.0次·min·kPa；35℃：-141.0±29.5对-28.7±6.4次·min·kPa，负值表示血压与通气（或呼吸频率）呈负相关，即血压升高时通气减少，反之亦然]，而温度对这些敏感性无影响。高氧（30%；25℃）使通气减少，但并未消除对低血压的通气反应，表明该反应独立于外周化学感受器。尽管此前有数据显示该物种在15至30℃时压力反射敏感性增加，但温度进一步升高（35℃）会降低压力反射增益（40.5±5.62对21.6±4.64%·kPa）。因此，除了在较高温度下肺通气参与使氧气输送与需求相匹配外，它在血压调节中也发挥作用，且与温度无关，这可能是由于压力反射与大脑呼吸区域之间的相互作用，正如之前对哺乳动物所提出的那样。
