Richard Bland

Publication Details

  • CHANGES IN LUNG LIQUID DURING SPONTANEOUS LABOR IN FETAL SHEEP JOURNAL OF APPLIED PHYSIOLOGY Chapman, D. L., Carlton, D. P., Nielson, D. W., Cummings, J. J., Poulain, F. R., Bland, R. D. 1994; 76 (2): 523-530

    Abstract:

    The goals of this study were 1) to examine changes in lung liquid formation and composition during spontaneous labor in fetal lambs and 2) to determine the importance of beta-adrenergic stimulation and transepithelial Na+ flux in removing liquid from the lung lumen near birth. We measured net production of lung liquid (Jv), lung liquid composition, and transpulmonary electrical potential difference (PD) before and during labor in fetal sheep with chronically implanted tracheal and vascular catheters. We determined Jv by measuring rate of change in lung liquid concentration of 125I-albumin, an impermeant tracer that was mixed in lung liquid at the start of each study. In 17 paired experiments, Jv decreased from 11 +/- 2 ml/h (Jv > 0 = secretion) before labor to -1 +/- 2 ml/h (Jv < 0 = absorption) during labor; in 5 paired experiments, PD changed from -7 +/- 1 mV (lumen negative) before labor to -12 +/- 1 mV during labor. To determine whether absorption of lung liquid during labor is the result of beta-adrenergic stimulation, we studied the effect of propranolol on Jv during labor. When propranolol (40 microM) was added to lung liquid during active labor, Jv decreased from -2 +/- 2 to -8 +/- 3 ml/h (n = 9). Thus, propranolol did not inhibit lung liquid absorption during labor. To determine whether transepithelial Na+ movement provides the driving force for lung liquid clearance during labor, we tested the effects of amiloride, an Na+ transport inhibitor, on Jv and PD.(ABSTRACT TRUNCATED AT 250 WORDS)

    View details for Web of Science ID A1994MX61000005

    View details for PubMedID 8175558

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