Showing papers by "University of Montpellier published in 1970"

Postnatal maturation in the cochlea of the cat.

Abstract: At birth, the cochlea of the cat, though generally developed, is still immature. Maturation of the organ of Corti begins at the base and gradually reaches the apex. In two weeks the process is complete. The most significant morphological criteria of the epithelial maturation are the formation of the tunnel of Corti and of the space of Nuel, the lengthening of the outer hair cells and the freeing of the internal spiral sulcus. On the third day after birth, the appearance of these criteria at the level of the first coil of the lamina spiralis coincides with the general physiological awakening of the auditory systems, as testified by the recording of evoked potentials from the cerebral cortex. Since such responses can be provoked by electrical stimulation of the nerve from birth onwards, the maturation of the organ of Corti appears to be the final stage in the development of the auditory system.

Effects of Starvation on Adrenal Cortical Function in the Rabbit

Abstract: The effects of progressive starvation were studied in female adult rabbits on the following parameters of adrenal cortical function: the plasma (P.C.) and adrenal (A.C.) corticosterone content, the biological half-life (t½), and the metabolic clearance rate (M.C.R.) of iv injected 3H-corticosterone, from which the adrenal secretion rate (S.R.) of the hormone could be calculated. Blood sugar was also assayed. No significant alteration of adrenal weight, either absolute or relative, was observed. After 24–48 hr starvation, a definite increase of adrenal cortical activity occurred, with marked increase of the P.C. and S.R., the t½ remaining unaltered, and the A.C. being lowered. This adrenal response was concomitant with a transient hypoglycemic phase. Prolongation of starvation (4–14 days) led to a picture of mild adrenal cortical depression, with t½ still normal, normal to subnormal P.C. and S.R. values, and marked A.C. decrease. Blood sugar was again normal. We concluded that, despite conspicuous body wei...