ASGSB 1998 Annual Meeting Abstracts

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HYPERGRAVITY & MICROGRAVITY EFFECTS TO AVIAN INNER EAR STRUCTURES. H. Hara, T. Jones§ & C.D. Fermin. Dept. Pathology. Tulane Univ. Medical School. New Orleans, LA 70112-2699 USA. §Surgery Dept. Univ. Missouri-Columbia, Missouri USA.

Because the avian inner ear: -completes its embryonic development in less than 21 days in the absence of parental care, -much information of avian embryology is available, and -has containment for waste and feces during development, made possible by semi-permeable membranes and a mineral shell, fertilized eggs are ideal for space research. Continuous exposure of embryos to 2xG affected the otolithic organs which are responsible for detection of linear acceleration. The most prominent morphological alterations of the macular epithelia which aids in the transduction of physical to neural energy, were

• displacement of capillaries,
• remodeling of the basement membrane
• alteration in the ratio of type I to type II afferent terminal endings and
• otoconia shape and size modifications.

Supporting and secretory cells may be affected by altered gravity less than sensory cells and/or changes induced by altered gravity to the non-sensory cells may be less persistent than sensory cells. Microgravity also affects neurons connecting the inner ear to the brain, but effects that microgravity may have on the nonsensory cells is unknown.

(Supported by NASA NAGW2-999, Tulane Pathology & Yamaguchi Univ., Japan

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