Journal of Applied Physiology, Vol 70, Issue 1 103-111, Copyright © 1991 by American Physiological Society

ARTICLES

Diaphragm capillarity and oxidative capacity during postnatal development

G. C. Sieck, T. S. Cheung and C. E. Blanco
Department of Biomedical Engineering, University of Southern California, Los Angeles 90089.

In the cat diaphragm, fiber capillarity, cross-sectional area, and succinate dehydrogenase (SDH) activity were measured across the first 6 wk of postnatal development. Fibers were classified as type I, IIa, IIb, or IIc on the basis of staining for myofibrillar adenosinetriphosphatase (ATPase). Capillaries were identified in sections stained for ATPase at pH 4.2. Fiber cross-sectional areas and SDH activities were quantified using an image-processing system. During postnatal development, the proportions of type I fibers increased while type II fibers decreased. At birth, all type II fibers were IIc. From the 1st to the 2nd postnatal wk, the proportion of type IIc fibers decreased while the numbers of IIa and IIb increased. Thereafter the proportion of type IIb fibers continued to increase while the number of IIa steadily declined. At birth, capillarity, cross-sectional areas, and SDH activities of type I and II fibers were low compared with other postnatal age groups. Fiber cross-sectional areas increased progressively with age. The number of capillaries surrounding type I and II fibers increased markedly by the 2nd wk and then continued to increase at a slower rate. The number of capillaries per fiber area reached a peak by the 2nd wk and then declined as fiber cross-sectional area increased. Postnatal changes in capillarity depended on fiber type, being greatest in IIb. SDH activities of type I and II fibers were initially low during the first 2 postnatal wk and then peaked by the 3rd wk. After the 6th wk, fiber SDH activities decreased to adult values. Among the type II fibers, IIb showed the greatest change in SDH activity during early postnatal development.

This article has been cited by other articles:

				C. B. Mantilla, R. V. Sill, B. Aravamudan, W.-Z. Zhan, and G. C. Sieck Developmental effects on myonuclear domain size of rat diaphragm fibers J Appl Physiol, March 1, 2008; 104(3): 787 - 794. [Abstract] [Full Text] [PDF]

				G. Orliaguet, O. Langeron, B. Bouhemad, P. Coriat, Y. LeCarpentier, and B. Riou Effects of postnatal maturation on energetics and cross-bridge properties in rat diaphragm J Appl Physiol, March 1, 2002; 92(3): 1074 - 1082. [Abstract] [Full Text] [PDF]

				M. Fournier and M. I. Lewis Influences of IGF-I gene disruption on the cellular profile of the diaphragm Am J Physiol Endocrinol Metab, April 1, 2000; 278(4): E707 - E715. [Abstract] [Full Text] [PDF]

				P. A. Kern, R. B. Simsolo, and M. Fournier Effect of Weight Loss on Muscle Fiber Type, Fiber Size, Capillarity, and Succinate Dehydrogenase Activity in Humans J. Clin. Endocrinol. Metab., November 1, 1999; 84(11): 4185 - 4190. [Abstract] [Full Text]

				G. Hilaire and B. Duron Maturation of the Mammalian Respiratory System Physiol Rev, April 1, 1999; 79(2): 325 - 360. [Abstract] [Full Text] [PDF]

				M. S. Biring, M. Fournier, D. J. Ross, and M. I. Lewis Cellular adaptations of skeletal muscles to cyclosporine J Appl Physiol, June 1, 1998; 84(6): 1967 - 1975. [Abstract] [Full Text] [PDF]

				W.-Z. Zhan, J. F. Watchko, Y. S. Prakash, and G. C. Sieck Isotonic contractile and fatigue properties of developing rat diaphragm muscle J Appl Physiol, April 1, 1998; 84(4): 1260 - 1268. [Abstract] [Full Text] [PDF]