MECHANISM OF RECTAL PROBE ELECTRICAL STIMULATION IN RELIEF OF SPASTICITY IN SPINAL CORD INJURY
Jianan Li, Fan Song, GX Xu (Nanjing Medical University, PR. China)
Abstract: Although effect of rectal probe electrical stimulation (RPES) in relief of spasticity in patients with spinal cord injury (SCI) has been confirmed clinically, its mechanism remains unclear. To clarify the mechanism of RPES in relief of spasticity, 20 SCI patients with spasticity were undertaken electrical physiological study after RPES and compared with the effects of Baclofen. The results showed significant decrease in amplification and duration of F wave and flexor reflex afferents (FRA), and F/M, T/H and H/M ratio after RPES, but not significant in H reflex threshold. After Baclofen admission, significant changes were found only in amplification and duration of FRA. All patients had significant relief of spasm after either RPES and Baclofen. The results suggest that mechanism of RPES in reief of spasticity in SCI might be attributed to augmentation of inhibitory interneuron activity and suppression of alpha and gamma motor neuron activity.
MUSCLE CONTRACTILE PROPERTIES AND SARCOLEMMAL PERMEABILITY AFTER UPHILL AND DOWNHILL RUNNING
Naohisa Kikuchi, Norihiko Ando (Yokohama City University, Yokohama, Japan)
Katsuhiko Tachino (Kanazawa University, Kanazawa, Japan)
Purpose: This study was undertaken to evaluate muscle contractile properties and sarcolemmal permeability of the hindlimbs of mice following uphill and downhill running.
Materials and Methods: 105 adult mice were divided into control, uphill and downhill treadmill running groups. Serum CK, contractile properties, and intracellular fluorescent dextran (FDX) stains were evaluated on postexercise days 0, 3 and 7.
Results: The serum CK level of the downhill group was significantly elevated more than the control group on day 0 and remained elevated till day 3. Tetanic, twitch tensions and twitch contraction time were significantly reduced on day 0 in both of groups. Intracellular FDX stain was faintly observed in the normal muscle cells on HE stain on day 0 in the downhill group. On the third postexercise day in the downhill group, clear intracellular FDX stain was observed in necrotic cells on HE stain, which was due to major damage of the sarcolemma. The uphill group did not show FDX stain on any day.
Conclusion: Both exhaustive uphill and downhill running can cause muscle injury immediately following exercise, but injury from the latter lasts longer.