1399 NASAL ELECTRIC POTENTIAL DIFFERENCE AND RESPONSE TO AMILORIDE SUPERFUSION IN NEONATES

Pulmonary epithelium changes after birth from Cl− secretion to Na+ absorption. To evaluate this transition, the maximal potential difference (PD) and the voltage response to superfusion with 10−5 M amiloride (Am), an inhibitor of Na+ absorption, were recorded between a Ringer perfused bridge placed on the nasal mucosa and a subcutaneous reference electrode. The PD was sequentially measured during the first 72 hrs of life across the nasal epithelium of healthy term neonates, healthy preterm neonates (29.7±0.3wks). neonates (30.2± 1.2wks) with Respiratory Distress Syndrome (RDS), and neonates (37.6± l.lwks) with Transient Tachypnea of the Newborn (TTNB). PDs (mean±SEM) and Am inhibition (%; at