Stimulation of sodium pump by vasoactive intestinal peptide in guinea‐pig isolated trachea: potential contribution to mechanisms underlying relaxation of smooth muscle

摘要: 1. Relaxation of airway smooth muscle induced by vasoactive intestinal peptide (VIP) is mediated adenosine 3':5' cyclic monophosphate (cyclic AMP). An interaction between the synthesis AMP and enzymic activity plasmalemmal sodium pump (Na(+)-K(+)-ATPase) exists in certain isolated cell systems. This study sought to determine contribution Na(+)-K(+)-ATPase relaxation evoked VIP. 2. All experiments were performed on strips guinea-pig trachea from which epithelium had been removed. VIP was a more potent relaxant tissues that contracted with carbachol than those an equi-effective depolarizing concentration K+. 3. Ouabain (0.1 microM-10 microM) contraction tracheal strips. Contraction ouabain (5 abolished following incubation K(+)-free, or Ca(2+)-free (+ EGTA, 0.1 mM) physiological solutions. The contractile response not influenced significantly exposure atropine (1 microM), phentolamine diphenhydramine for 60 min. 4. Tissues incubated microM; min) K(+)-free solution (60 inhibit activity. These procedures reduced VIP, histidine isoleucine, forskolin, isoprenaline nitroprusside. 5. impaired low Na+ (30 amiloride (500 30 min). 6. Ouabain-sensitive uptake 86Rb measured (devoid cartilage) as index 2 caused 4.7 fold stimulation ouabain-sensitive 86Rb. effect solution. 7. results suggest (i) sensitive invoke role altered function mechanisms underlie AMP-dependent relaxation; (ii) stimulates Na(+)-dependent manner.