Why the study?
Does alpha- or beta-adrenergic blockade alter the capacity of coronaries for hypoxic dilatation in open chest dogs?
Does alpha- or beta-adrenergic blockade alter the capacity of coronaries for hypoxic dilatation in open chest dogs?
In a canine model, alpha-adrenergic blockade with phentolamine, but not beta-blockade with propranolol, significantly limits coronary adaptation to hypoxia.
Alpha-blockade limits hypoxic coronary adaptation in dogs unlike beta-blockade; leaves open relevance to human coronary physiology.
The effect of 2 types of adrenergic blockade on the capacity of the coronaries for hypoxic dilatation was studied in open chest dogs under chloralose anesthesia. Reactive hyperemia following the temporary occlusion of the left coronary artery and the vasodilatation elicited by general arterial hypoxia served to determine the range of coronary adaptation. beta-adrenergic blockade induced by propranolol (0.3 mg/Kg i.v. or 0.05 mg/Kg intracoronarially) failed to reduce the range of hypoxic dilatation. On the other hand, the alpha-blocking agent phentolamine (0.45 mg/Kg i.v. or 0.15 mg/Kg i.c.), in association with a decrease of the vascular tone, significantly limited the coronary adaptation to hypoxia.
No takes yet. Share an insight, caveat, or question.
Juhász‐Nagy et al. (1976) studied this question.
Synapse has enriched 5 closely related papers on similar clinical questions. Consider them for comparative context: