Gregory N G, Wotton S B
J Vet Pharmacol Ther. 1981 Sep;4(3):183-91. doi: 10.1111/j.1365-2885.1981.tb00729.x.
The T-wave characteristics, heart rate, stroke volume, cardiac output and blood pressure were examined in acidosis-prone Pietrain and acidosis-resistant Gloucester Old Spot pigs, before and after autonomic blockade with propranolol, atropine and phentolamine. Assessments were made at normal arterial blood pH and pCO2, and at either the same age or live weight in the two breeds. T-wave amplitude was influenced by alpha-adrenergic activity in the absence of beta-adrenergic and parasympathetic receptor activation. The initial cardiac output was 25% greater in the Pietrains, and 75% of this breed difference was due to autonomic factors. Myocardial chronotropic responsiveness to noradrenaline was similar in the two breeds. Initial blood pressure was greater in the Gloucester Old Spots because of a non-autonomic factor, and vasopressor responsiveness to noradrenaline was greater in the Gloucester Old Spots. Although acidosis-prone pigs may be afforded some degree of protection from a sympathetic crisis by having a low vasopressor responsiveness to adrenoreceptor stimulation, enhanced catecholamine output is the likely cause of their stress-induced myocardial lesions. A high catecholamine output may also account for the reduced body fatness in this type of pig.
在用普萘洛尔、阿托品和酚妥拉明进行自主神经阻滞前后，对易发生酸中毒的皮特兰猪和耐酸中毒的格洛斯特老斑点猪的T波特征、心率、每搏输出量、心输出量和血压进行了检测。评估是在正常动脉血pH值和pCO₂水平下，以及在两个品种相同年龄或相同体重时进行的。在没有β-肾上腺素能和副交感神经受体激活的情况下，T波振幅受α-肾上腺素能活性影响。皮特兰猪的初始心输出量高出25%，该品种差异的75%归因于自主神经因素。两个品种对去甲肾上腺素的心肌变时反应相似。由于非自主神经因素，格洛斯特老斑点猪的初始血压更高，且对去甲肾上腺素的升压反应在格洛斯特老斑点猪中更强。尽管易发生酸中毒的猪对肾上腺素能受体刺激的升压反应较低，可能在一定程度上免受交感神经危机的影响，但儿茶酚胺输出增加可能是其应激性心肌损伤的原因。高儿茶酚胺输出也可能是这类猪体脂减少的原因。
