Possible role of endogenous catecholamines in the contractions induced in rabbit aorta by ouabain, sodium depletion and potassium depletion.
Effects of ouabain, Na+ depletion and K+ depletion on the tension development of rabbit aorta were studied. Contraction in the strips was induced by ouabain and Na+-free solution substituted with Li+, tris or sucrose. The contractions were rarely seen under alpha-adrenergic blockade, in reserpinized aorta and mechanically denervated aorta. Contractions induced by norepinephrine were potentiated by Na+ depletion, K+ depletion and ouabain. Contractions induced by high K+ solution were also potentiated by Na+ depletion and ouabain. The potentiation in Li+ solution, K+-free solution and with ouabain was not seen under alpha-adrenergic blockade, in reserpinized aorta and denervated aorta although the potentiation by tris and sucrose solutions was still observed. These data suggest that Na+ depletion, K+ depletion and ouabain release endogenous catecholamines which affect the contraction of the vascular smooth muscle of rabbit aorta.
D000818:Animals; D001013:Aorta, Thoracic / Q000187:drug effects / Q000502:physiology; D002395:Catecholamines / Q000502:physiology*; D004347:Drug Interactions; D005260:Female; D066298:In Vitro Techniques; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects*; D009126:Muscle Relaxation / Q000187:drug effects; D009129:Muscle Tonus / Q000187:drug effects; D009130:Muscle, Smooth / Q000187:drug effects* / Q000502:physiology; D009638:Norepinephrine / Q000494:pharmacology; D010042:Ouabain / Q000494:pharmacology*; D011188:Potassium / Q000502:physiology*; D011817:Rabbits; D012964:Sodium / Q000502:physiology*; D013997:Time Factors
D002395:Catecholamines; D010042:Ouabain; D012964:Sodium; D011188:Potassium; D009638:Norepinephrine