GLUCOSE-UTILIZATION OF THE RAT VESTIBULAR END ORGANS - A QUANTITATIVE2-DEOXYGLUCOSE STUDY

The local metabolic rate of glucose utilization (LMRglc) for the rat v estibular end organs was determined with a modification of the [C-14]d eoxyglucose method. Data are expressed as micromoles per 100 g per min ute +/- SEM. Results indicate that the LMRgle is similar within the ut ricle (40.3 +/- 3.2) and saccule (41.2 +/- 5.5) and significantly high er than that for the superior (20.1 +/- 2.9), posterior (25.4 +/- 2.0) , or lateral canal (22.0 +/- 2.6) ampullae. These differences in LMRgl c may be related to differences in the ratios of sensory to nonsensory cells, dark cell distributions, response to acoustic stimulation, or activity levels during the experimental period. Given the high blood f low rates reported for the vestibular end organs by Lyon and coworkers , a much higher LMRglc Was expected. Together, these data would sugges t that delivery of metabolites is not a primary regulating force for v estibular blood flow. Instead, the primary reason for a high blood flo w rate may be waste removal, the maintenance of pH, ion balance, and/o r temperature.