Rodman Joshua R, Henderson Kathleen S, Smith Curtis A, Dempsey Jerome A
Department of Population Healh Sciences, The University of Wisconsin-Madison, Wisconsin 53726, USA.
J Appl Physiol (1985). 2003 Sep;95(3):1159-69. doi: 10.1152/japplphysiol.00258.2003. Epub 2003 May 16.
In awake dogs, lactic acid was injected into the phrenic and deep circumflex iliac arteries to elicit the diaphragm and abdominal muscle metaboreflexes, respectively. At rest, injections into the phrenic or deep circumflex iliac arteries significantly increased mean arterial blood pressure 21 +/- 7% and reduced cardiac output 6 +/- 2% and blood flow to the hindlimbs 20 +/- 9%. Simultaneously, total systemic, hindlimb, and abdominal expiratory muscle vascular conductances were reduced. These cardiovascular responses were not accompanied by significant changes in the amplitude or timing of the diaphragm electromyogram. During treadmill exercise that increased cardiac output, hindlimb blood flow, and vascular conductance 159 +/- 106, 276 +/- 309, and 299 +/- 90% above resting values, lactic acid injected into the phrenic or deep circumflex iliac arteries also elicited pressor responses and reduced hindlimb blood flow and vascular conductance. Adrenergic receptor blockade at rest eliminated the cardiovascular effects of the respiratory muscle metaboreflex. We conclude that the cardiovascular effects of respiratory muscle metaboreflex activation are similar to those previously reported for limb muscles. When activated via metabolite production, the respiratory muscle metaboreflex may contribute to the increased sympathetic tone and redistribution of blood flow during exercise.
在清醒犬中，将乳酸分别注入膈动脉和旋髂深动脉，以分别引发膈肌和腹部肌肉的代谢性反射。静息时，向膈动脉或旋髂深动脉注射乳酸可使平均动脉血压显著升高21±7%，心输出量降低6±2%，后肢血流量降低20±9%。同时，全身、后肢和腹部呼气肌的血管传导率均降低。这些心血管反应并未伴随膈肌肌电图的幅度或时间出现显著变化。在使心输出量、后肢血流量和血管传导率比静息值分别增加159±106%、276±309%和299±90%的跑步机运动期间，向膈动脉或旋髂深动脉注射乳酸也会引发升压反应，并降低后肢血流量和血管传导率。静息时的肾上腺素能受体阻断消除了呼吸肌代谢性反射的心血管效应。我们得出结论，呼吸肌代谢性反射激活的心血管效应与先前报道的肢体肌肉的效应相似。当通过代谢产物生成激活时，呼吸肌代谢性反射可能有助于运动期间交感神经张力的增加和血流的重新分布。
