No abstract

An immunocytochemical comparison of vGluT1 and vGluT3 in the cochlear nucleus (CN) of deafened versus normal hearing rats showed the first example of vGluT3 immunostaining in the dorsal and ventral CN and revealed temporal and spatial changes in vGluT1 localization in the CN after cochlear injury. In normal hearing rats vGluT1 immunostaining was restricted to terminals on CN neurons while vGluT3 immunolabeled the somata of the neurons. This changed in the VCN three days following deafness, where vGluT1 immunostaining was no longer seen in large auditory nerve terminals but was instead found in somata of VCN neurons. In the DCN, while vGluT1 labeling of terminals decreased, there was no labeling of neuronal somata. Therefore, loss of peripheral excitatory input results in co-localization of vGluT1 and vGluT3 in VCN neuronal somata. Postsynaptic glutamatergic neurons can use retrograde signaling to control their presynaptic inputs and these results suggest vGluTs could play a role in regulating retrograde signaling in the CN under different conditions of excitatory input. Changes in vGluT gene expression in CN neurons were found three weeks following deafness using qRT-PCR with significant increases in vGluT1 gene expression in both ventral and dorsal CN while vGluT3 gene expression decreased in VCN but increased in DCN.

Failure of the primary lip and palate to fuse leads to clefts of the lip, a birth defect with an incidence of 1 for every 500 in some races. Epithelial cells lining the facial processes of the primary lip and palate, the lateral and medial nasal processes (LNP and MNP), must first make contact to go through a series of highly regulated and coordinated sequence of events to form the normal midface. As yet, many of the basic mechanisms underlying the fusion events of the epithelial-lined surfaces are not known. This is due in part to the difficulty associated with the isolation of the epithelial cells for further study and analysis. The objective of this study was to test the use of laser capture microdissection to collect clean populations of primary lip and palate epithelial cells destined to fuse. Fusing and nonfusing epithelial cell populations of the MNP and LNP were isolated by laser capture microdissection and assayed for gene expression of Bmp-4, Tgfβ-2, and their type 1 receptors, Alk-3 and Alk-5, respectively. Transcripts of Bmp-4/Alk-3 and Tgfβ-2/Alk-5 were restricted to the epithelial seam of the fusion site, and the epithelium of the prefusion site, in patterns previously reported. Data indicated our ability to isolate clean populations of epithelial and mesenchymal cells around the primary palate fusion site, allowing precise analysis of tissue and site-specific gene expression at high resolution. This study provides the basis of further analysis of the potential molecular players of MNP and LNP fusion and nonfusion of epithelial cells.

No abstract

An experiment was conducted to determine the effects and interactions of exercise-retirement and dietary fat intake on body composition and hepatic lipogenic enzyme activities in hamsters. Forty-eight adult female hamsters were randomly allotted to eight groups of six each for a 40-d experiment. Exercise was in the form of voluntary wheel-running. Four groups served as either exercise or sedentary controls and were fed either a low or a high fat diet for 40 d, in a factorial fashion. Another four groups had access to exercise for 32 d and were then retired for 8 d. Of these four groups, two were fed either the low or high fat diet for the entire 40-d period; the other two were changed to the other diet on d 32. Results showed that compared to sedentary hamsters, exercise hamsters had greater body weight gain but less body fat content and hepatic lipogenic enzyme activities. Under both sedentary and exercise conditions, high fat-fed hamsters had lower hepatic lipogenic enzyme activities and less body fat content than low fat-fed hamsters. Upon retirement, high fat feeding led to a faster increase in body fat especially in previously high fat-fed hamsters. Results of this study suggest that dietary fat intake can significantly modulate the exercise and retirement effects with respect to body weight gain and body fat content.