Hageman G R, Urthaler F, James T N
Am J Physiol. 1977 Aug;233(2):H211-6. doi: 10.1152/ajpheart.1977.233.2.H211.
This investigation determined the chronotropic effects of norepinephrine and acetylcholine (ACh) administered selectively into the canine sinus node artery after cardiac denervation. In 42 dogs the cervical vagi were isolated, the heart was exposed, and vagal stimulations were performed before and after sham procedure or extrinsic cardiac parasympathectomy. Four additional dogs underwent bilateral stellectomy. The dogs were reanesthetized 4-23 days later, and blood pressure, heart rate, ECG, and local cardiac electrograms were recorded. The vagi were again stimulated and the effectiveness of the parasympathectomy was verified in 11 of the dogs. On selective perfusion of the sinus node with 0.001- to 1-microgram doses of ACh, the sinus bradycardias of the parasympathectomized and the sham-operated dogs were not significantly different. The responses to norepinephrine (0.01 and 0.1 microgram/ml) administered via the same route in the stellectomized dogs were significantly greater than those in the sham-operated dogs, thus verifying this technique for the assessment of sinus node sensitivity to neurotrasmitters. We conclude that extrinsic denervation of the canine sinus node leads to development of a differential response between adrenergic and cholinergic neurotransmitters. These differential sensitivities may be important when considering the pharmacological responses and electrical stability of the denervated and/or transplanted heart.
本研究确定了在心脏去神经支配后，选择性地向犬窦房结动脉注射去甲肾上腺素和乙酰胆碱（ACh）的变时效应。在42只犬中，分离出颈迷走神经，暴露心脏，并在假手术或心脏外副交感神经切除术前和术后进行迷走神经刺激。另外4只犬接受双侧星状神经节切除术。4至23天后，再次对犬进行麻醉，记录血压、心率、心电图和局部心脏电图。再次刺激迷走神经，并在11只犬中验证了副交感神经切除术的有效性。在用0.001至1微克剂量的ACh选择性灌注窦房结时，副交感神经切除犬和假手术犬的窦性心动过缓无显著差异。在星状神经节切除犬中，通过相同途径给予去甲肾上腺素（0.01和0.1微克/毫升）时的反应明显大于假手术犬，从而验证了该技术可用于评估窦房结对神经递质的敏感性。我们得出结论，犬窦房结的外在去神经支配导致肾上腺素能和胆碱能神经递质之间出现差异反应。在考虑去神经支配和/或移植心脏的药理反应和电稳定性时，这些差异敏感性可能很重要。
