| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
Department of Pediatrics, The Johns Hopkins Children's Center, Baltimore, Maryland 21287
The O2 sensitivity of carotid chemoreceptor type I cells is low just after birth and increases with postnatal age. Chronic hypoxia during postnatal maturation blunts ventilatory and carotid chemoreceptor neural responses to hypoxia, but the mechanism remains unknown. We tested the hypothesis that chronic hypoxia from birth impairs the postnatal increase in type I cell O2 sensitivity by comparing intracellular Ca2+ concentration ([Ca2+]i) responses to graded hypoxia in type I cell clusters from rats born and reared in room air or 12% O2. [Ca2+]i levels at 0, 1, 5, and 21% O2, as well as with 40 mM K+, were measured at 3, 11, and 18 days of age with use of fura 2 in freshly isolated cells. The [Ca2+]i response to elevated CO2/low pH was measured at 11 days. Chronic hypoxia from birth abolished the normal developmental increase in the type I cell [Ca2+]i response to hypoxia. Effects of chronic hypoxia on development of [Ca2+]i responses to elevated K+ were small, and [Ca2+]i responses to CO2 remained unaffected. Impairment of type I cell maturation was partially reversible on return to normoxic conditions. These results indicate that chronic hypoxia severely impairs the postnatal development of carotid chemoreceptor O2 sensitivity at the cellular level and leaves responses to other stimuli largely intact.
carotid chemoreceptors; maturation; calcium; birth
This article has been cited by other articles:
|
|
 |
|
  A. Pawar, Y.-J. Peng, F. J. Jacono, and N. R. Prabhakar Comparative analysis of neonatal and adult rat carotid body responses to chronic intermittent hypoxia J Appl Physiol, May 1, 2008; 104(5): 1287 - 1294. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
R. W. Bavis and G. S. Mitchell Long-term effects of the perinatal environment on respiratory control J Appl Physiol, April 1, 2008; 104(4): 1220 - 1229. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 A. Balbir, H. Lee, M. Okumura, S. Biswal, R. S. Fitzgerald, and M. Shirahata A search for genes that may confer divergent morphology and function in the carotid body between two strains of mice Am J Physiol Lung Cell Mol Physiol, March 1, 2007; 292(3): L704 - L715. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
C. Kantores, P. J. McNamara, L. Teixeira, D. Engelberts, P. Murthy, B. P. Kavanagh, and R. P. Jankov Therapeutic hypercapnia prevents chronic hypoxia-induced pulmonary hypertension in the newborn rat Am J Physiol Lung Cell Mol Physiol, November 1, 2006; 291(5): L912 - L922. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
Y.-J. Peng, J. Rennison, and N. R. Prabhakar Intermittent hypoxia augments carotid body and ventilatory response to hypoxia in neonatal rat pups J Appl Physiol, November 1, 2004; 97(5): 2020 - 2025. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. L. Carroll Plasticity in Respiratory Motor Control: Invited Review: Developmental plasticity in respiratory control J Appl Physiol, January 1, 2003; 94(1): 375 - 389. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
R. W. Bavis, E. B. Olson Jr., and G. S. Mitchell Critical developmental period for hyperoxia-induced blunting of hypoxic phrenic responses in rats J Appl Physiol, March 1, 2002; 92(3): 1013 - 1018. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
D. D. Kline, T. Yang, D. R. D. Premkumar, A. J. Thomas, and N. R. Prabhakar Blunted respiratory responses to hypoxia in mutant mice deficient in nitric oxide synthase-3 J Appl Physiol, April 1, 2000; 88(4): 1496 - 1508. [Abstract] [Full Text] [PDF]
|
|
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| Visit Other APS Journals Online |
