Meeting Abstract

P3.78  Thursday, Jan. 6  New methods for imaging hibernation marks in the incremental dentin of rodent incisors BATAVIA, M.; University of California, Berkeley mbatavia@berkeley.edu

Dentin is deposited in a circadian fashion in ever-growing rodent incisors. Numerous studies have documented a distinct, contrasting layer that corresponds to periods of hibernation in a number of rodent species. Previous methods of visualizing and characterizing this hibernation mark (HM) include (1) histological preparation and (2) examination of the medial surface of the incisor. The medial surface lacks enamel, leaving exposed the dentin increments, which are visible with oblique lighting under a dissecting microscope. Both these methods have limitations: histological sampling is destructive, and is therefore not ideal for the study of museum specimens. Imaging the medial surface of the tooth is difficult, unreliable for some taxa, and time-consuming. Several novel approaches to visualizing the HM are presented, including the use of high resolution X-ray microtomography and scanning electron microscopy. These techniques are used to assess the relationship between HM morphology and torpor bout depth, bout length, and arousal frequency in Turkish hamsters (Mesocricetus brandti).