INTERSPECIED VARIATIONS IN THE HISTOLOGY OF TOXICOLOGICALLY IMPORTANTAREAS IN THE LARYNGES OF CRL-CD RATS AND SYRIAN GOLDEN-HAMSTERS

Specific regions in the rodent larynx exhibit cellular changes in resp onse to inhaled xenobiotics. These regions include the base of the epi glottis, ventral pouch, and medial surfaces of the vocal processes of the arytenoid cartilages. There are interspecies differences among lab oratory rodents in the microscopic anatomy of these sensitive areas of the laryngeal mucosa. In CRL:CD strain Sprague-Dawley rats, the mucos a covering the epiglottis differs from that of Syrian golden hamsters. The epithelium covering the base of the epiglottis is relatively thin in rats and is composed of a mixture of cell types, whereas in hamste rs it is much thicker and is made up almost entirely of tall ciliated columnar cells. The cartilage supporting the ventral pouch in the lary nges of hamsters is much more prominent than in rats and forms a disti nct protrusion into the laryngeal lumen at the base of the epiglottis. The purpose of this paper is to describe and illustrate these and oth er subtle differences in rat and hamster laryngeal anatomy, which may be of toxicologic significance.