Coronary vascular response to adrenergic stimulation in exercise-conditioned dogs
| Autor: | P. A. Gwirtz, H. L. Stone |
|---|---|
| Rok vydání: | 1984 |
| Předmět: |
Physiology
Hemodynamics Blood Pressure Propranolol Coronary circulation Dogs Phentolamine Heart Rate Physical Conditioning Animal Physiology (medical) Heart rate medicine Animals Sympathomimetics business.industry Atenolol Coronary Vessels Stimulation Chemical Receptors Adrenergic medicine.anatomical_structure Regional Blood Flow Anesthesia Coronary vessel Circulatory system Sympatholytics business medicine.drug |
| Zdroj: | Journal of Applied Physiology. 57:315-320 |
| ISSN: | 1522-1601 8750-7587 |
| DOI: | 10.1152/jappl.1984.57.2.315 |
| Popis: | The present study was designed to determine whether daily exercise alters adrenergic and muscarinic neural control of coronary blood flow during resting and exercising conditions in the conscious dog. Mean left circumflex artery blood flow (CBF), mean coronary blood pressure, and heart rate were measured during resting conditions (55 +/- 9 ml/min, 108 +/- 6 mmHg, and 93 +/- 2 beats/min, respectively) and during submaximal exercise (85 +/- 9 ml/min, 108 +/- 7 mmHg, and 210 +/- 15 beats/min). Injection of phentolamine into the left circumflex coronary artery during treadmill exercise resulted in a 10 +/- 1% increase in CBF before training (untrained, UT) and a 21 +/- 6% increase after 4–5 wk of daily exercise (partially trained, PT) (P less than 0.02 UT vs. PT). Intracoronary atenolol or propranolol caused a 15 +/- 6% reduction in CBF during exercise in dogs before and after PT. While the dogs were lying quietly at rest intracoronary injections of norepinephrine initially increased CBF 85%, followed by a prolonged 19 +/- 9% decrease in CBF. CBF decreased 16 +/- 3% after intracoronary injection of phenylephrine. After PT the coronary vasoconstriction following norepinephrine and phenylephrine injections was significantly potentiated (31 +/- 6 and 35 +/- 4%, respectively). These data suggest that exercise training caused significant changes in the coronary vascular response to alpha-receptor stimulation so that an alteration in the neural control of the coronary circulation occurred. |
| Databáze: | OpenAIRE |
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