[Abstract Title]. - Society for Neuroscience

Support: NIH MBRS-SCORE grant 1s06GM067078-01A2
Title: The effect of uncontrolled diabetes on rat movement behavior
Authors: M. MARTIN, B. SOWELL, C. SPEARS, *V. K. HAFTEL;
Dept of Biol., Morehouse Col., Atlanta, GA
Abstract: Over 230 million people in the world are affected by diabetes (type I and type II). At
least 177 million of these people suffer from secondary complications. Neuropathy is one such
complication that can lead to numbness, tingling, pain and weakness of hands and feet, and
movement disorders. Movement disorders in diabetic patients may be due, at least in part to
deficits in function of proprioceptors mediating posture and gait. Electrophysiological records of
proprioceptor function collected in this lab (Benedict et al., 2005, SFN abstr.) demonstrate
significantly increased conduction velocity and altered firing patterns in proprioceptive spindle
afferent axons following 3 wks of STZ-induced diabetes in rats. Subsequent studies at this early
stage showed that proprioceptor function could not be explained by gross morphological
changes, and that movement was not apparently affected (Adams et al., 2007, SFN abstr.). This
study seeks to expand these data to determine whether longer periods (up to 8 wks) of
uncontrolled diabetes would cause changes in rats‟ ability to walk across a beam or grid. To do
so, as before, rats were injected with streptozotocin (55 mg/kg, IP) to create a model of diabetes.
Rats were checked for diabetes after 48 hours by measuring blood and urine glucose. Blood and
urine was tested weekly thereafter. The number of hind foot slips was counted when walking
across a wide metal beam, a grid, or a challenging narrow metal beam each week for 8 wks
following confirmation of hyperglycemia. Although the average number of slips increased from
wk 3 to wk 8 for grid and narrow beam walking, it was not significant (wide beam: wk 3, 1.0 +/-
0.57 slips vs. wk 8, 0.33 +/- 0.33 slips, p = 1.00; grid: wk 3, 0 slips vs. wk 8, 2.0 +/- 1.2 slips, p =
1.00; narrow beam: wk 3, 0.67 +/- 0.33 slips vs. wk 8, 1.33 +/- 0.88 slips, p = 1.00; mean number
slips +/- S.E.; repeated measures ANOVA with Tukey HSD posthoc test). Rats did seem to
compensate their movements (crouching and crawling, hopping, limping) in order to cross the
apparatus, but these compensations could not easily be quantified. Additional analysis of gait
was done using the Sciatic Function Index (Bain et al., 1989) to determine whether movement
disruptions could be detected. Rats demonstrated a loss of function with SFI values < 0 (left
foot= -21.6, right foot = -18.0, where 0 is normal and -100 is total dysfunction). These data show
that neuronal changes may take even longer to be reflected in movement behavior, and that
behavioral changes may manifest in subtle ways. Further information on proprioceptor
morphology and function will be gathered for the 6-8 week time period, as well as motoneuron
function.
Disclosures: M. Martin, None; B. Sowell, None; V.K. Haftel , None; C. Spears, None.
Poster
272. Kinematics and EMG: Diseases