Department of Physiology, University of São Paulo (USP), São Paulo, SP, Brazil.
Department of Zoology and Botany, São Paulo State University (UNESP), São José do Rio Preto, SP, Brazil.
J Exp Zool A Ecol Integr Physiol. 2021 Mar;335(3):348-358. doi: 10.1002/jez.2448. Epub 2021 Jan 27.
The most commonly used technique to study the barostatic regulation of blood pressure in ectothermic vertebrates consists of determining the heart rate response to pharmacological manipulations of blood pressure, the so-called "Oxford method." Although well established, the Oxford method has some important limitations, such as induction of hypervolemia in small animals and undesired effects of vasoactive drugs on central and peripheral baroreflex components. As an alternative, the sequence method, which consists in the computerized evaluation of naturally-occurring baroreflex adjustments of heart rate without the need for pharmacological administrations, was developed to study baroreflexes. In the present study, we compare this sequence method with the Oxford technique in two teleost species with different life styles, and we assess the optimal software configuration for the employment of the sequence method in fish. Calculation of baroreflex gain through the sequence method was adequate and reliable when the software was configured to search for baroreflex sequences with a minimum length of three cardiac cycles with a delay of one cardiac cycle between fluctuations in mean ventral aortic blood pressure and reflex changes in pulse interval. When properly configured, the sequence and the Oxford methods yielded similar determinations of the baroreflex gain in fish.
最常用于研究变温脊椎动物血压的静压调节的技术包括确定心率对血压的药物处理的反应，即所谓的“牛津方法”。尽管该方法已经得到很好的确立，但仍存在一些重要的局限性，例如在小动物中引起血容量过多以及血管活性药物对中枢和外周压力反射成分的不良影响。作为替代方法，序列方法被开发出来，用于研究压力反射，该方法包括在不需要药物给药的情况下，通过计算机评估心率的自然发生的压力反射调整。在本研究中，我们将该序列方法与两种具有不同生活方式的硬骨鱼进行比较，并评估了在鱼类中使用序列方法的最佳软件配置。当软件配置为搜索具有三个心动周期的最小长度的压力反射序列，并在平均腹主动脉血压波动和脉搏间隔反射变化之间延迟一个心动周期时，通过序列方法计算的压力反射增益是充分和可靠的。当正确配置时，序列和牛津方法在鱼类中的压力反射增益的测定结果相似。
