West N H, Van Vliet B N
Am J Physiol. 1983 Nov;245(5 Pt 1):R642-50. doi: 10.1152/ajpregu.1983.245.5.R642.
In the conscious toad, Bufo marinus, heart rate responses to manipulations of arterial pressure by vascular occlusion confirm that receptors sensitive to changes in intravascular pressure are located in the pulmocutaneous arteries. The cardiovascular responses to electrical stimulation of the central end of the laryngeal branch of the vagosympathetic trunk indicate that their afferents lie within this nerve. Inflation of an isolated pulmocutaneous sac in conscious toads in which the contralateral laryngeal nerve was cut resulted in a reduction of mean aortic pressure, with an associated bradycardia in some animals. Maximum open-loop gain for the relationship between sac pressure and aortic pressure was 0.35 +/- 0.06 (n = 5), resulting in a predicted maximum closed-loop gain of 0.25 +/- 0.03. Maximum gain occurred at 4.0-6.0 kPa, which was higher than the normal range of mean pulmocutaneous pressures in conscious undisturbed B. marinus, suggesting that the baroreceptors may be more effective in compensating for a rise than for a fall in pressure. This functional characteristic of the receptors suggests that not only may they modulate mean pressure in both the systemic and pulmocutaneous circuits, but that they may be particularly important in protecting the lung vasculature from excessive hydrostatic pressures.
在清醒的海蟾蜍（Bufo marinus）中，通过血管闭塞对动脉压进行操作时的心率反应证实，对血管内压力变化敏感的感受器位于肺皮动脉中。对迷走交感干喉支中枢端进行电刺激时的心血管反应表明，其传入神经位于该神经内。在清醒的海蟾蜍中，对侧喉神经被切断后，孤立的肺皮囊充气会导致平均主动脉压降低，部分动物还伴有心动过缓。肺皮囊压力与主动脉压力之间关系的最大开环增益为0.35±0.06（n = 5），预测的最大闭环增益为0.25±0.03。最大增益出现在4.0 - 6.0 kPa，高于清醒未受干扰的海蟾蜍正常肺皮平均压力范围，这表明压力感受器在补偿压力升高方面可能比补偿压力降低更有效。感受器的这一功能特性表明，它们不仅可能调节体循环和肺皮循环中的平均压力，而且在保护肺血管系统免受过高静水压方面可能特别重要。
