DNA content, mitotic activity, and incorporation of tritiated thymidine in the developing inner ear of the rat
The rat inner ear is ectodermally derived from a region adjacent to the developing hindbrain. Beginning on day 8 of a 22-day gestational period, This zone of ectoderm first forms the otic placode, then the otocyst, and ultimately the definitive membranous labyrinth. This report provides an estimation of total DNA content of the developing inner ear, and hence an estimation of the total number of cells that comprise the inner ear at each developmental stage. The incorporation of /sup 3/H-thymidine indicates that most cells of the inner ear undergo DNA synthetic activity during gestational days 13 to 15. Radioautographic observations indicate a zone of DNA synthetic activity at the base of the outpocketing cochlear duct during early development. At the later stages of development, DNA synthesis is restricted to the cristae ampullares of the semicircular canals and the maculae of the utricle and the saccule. In contradistinction to the findings of other investigators, the statoacoustic ganglion complex undergoes terminal mitosis during gestational days 17 and 18. The gestational period between days 13 and 15 may prove to be a critical stage in normal otic development. The normal values of total DNA content and the number of cells that comprise the inner ear during development, established by these methods, can be compared with pathologic inner ears to provide quantitative means of assessing the damage in malformed inner ears. These values also form the baseline for future experimental studies of inner ear development.
- Research Organization:
- Department of Aatomy, Mount Sinai School of Medicine, NY
- OSTI ID:
- 6778769
- Journal Information:
- Anat. Rec.; (United States), Journal Name: Anat. Rec.; (United States) Vol. 202:4; ISSN ANREA
- Country of Publication:
- United States
- Language:
- English
Similar Records
Correlation between auditory brainstem recordings and morphology as seen through the scanning electron microscope
RADIATION AND EAR: EXPERIMENTAL STUDIES
Related Subjects
550301 -- Cytology-- Tracer Techniques
551001* -- Physiological Systems-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ANIMALS
AUDITORY ORGANS
AZINES
BODY
CELL DIVISION
DNA
HETEROCYCLIC COMPOUNDS
ISOTOPE APPLICATIONS
LABELLED COMPOUNDS
MAMMALS
MITOSIS
NUCLEIC ACIDS
NUCLEOSIDES
NUCLEOTIDES
ONTOGENESIS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
ORGANS
PYRIMIDINES
RATS
RIBOSIDES
RODENTS
SENSE ORGANS
THYMIDINE
TRACER TECHNIQUES
TRITIUM COMPOUNDS
VERTEBRATES