P-2-08-05
INFLUENCE OF ELECTRICAL STIMULATION ON THE CONTRACTILE PROPERTIES AND FATIGABILITY OF THE HUMAN PARALYZED MUSCLE
M. Masuda, R. Yagi, K. Ihashi and Y. Handa (Tohoku University Graduate School of Medicine, Sendai, Japan)
Abstract: The purpose of this study was to evaluate the changes in the contractile properties and fatigability of the paralyzed vastus lateralis muscle following therapeutic electrical stimulation (TES). Three paraplegics had sustained complete spinal cord injury at least one year before TES. TES with a frequency of 20Hz was applied for 15min, from 6 to 8 times a day. To assess the changes in the muscle properties, electrically induced isometric tension was measured by using strain gauges. The contractile properties were examined by applying a stimulus train of 500ms duration with frequencies of 10, 20, 30, 40 and 50Hz. Fatigability was studied during a continuous train of stimuli for 60s at 20 and 50Hz, respectively. The trace of 10Hz was incomplete fusion at the beginning of TES treatment. The fluctuation decreased with TES training. Finally, such fluctuation fused completely after 360 hours of TES. The tension was rapidly decreased during continuous stimulation of both frequencies at 50 hours of TES. The muscle could maintain the tension at 200 hours of TES. These result suggested that paralyzed muscle came to have a slow twitch property and a fatigue resistance with a long-term TES training. It is concluded that the program of our TES training was suitable for obtaining the optimum muscle properties to stand by functional electrical stimulation.
P-2-09-01
NORADRENALINE AND CARBACHOLINE CHANGE THE TIME COURSE OF THE EVOKED QUANTA MEDIATOR RELEASE FROM THE MOTOR NERVE TERMINAL
Ellya Bukharaeva, E. Nikolsky, R. Gainulov, F. Vyskocil *(Medical University, Kazan, Russia, *Karlov University, Prague, Czechia)
The effects of unhydrolysed analogue of acetylcholine - carbacholine (CCH) and noradrenaline (NA) on the time course of the evoked mediator release at the amphybian nerve-muscle junction were investigated. The secretion kinetic was estimated by measuring the real synaptic delay (SD) of the one-quantal endplate currents (EPC). It was found that the CCH (10 mkmol/l) along with the depression of the quantal content by 30% caused a notable increase of the asymmetry of the SD histograms through the EPC with the larger SD. The analysis of the cumulative curves for SD in control and under CCH showed that the value of quantil at the 90% level - P90 (this is the time interval in that contained 90% values of SD) increased from 804±45 ms (n=9) in control to 1293±173 (n=9, P<0.05) under CCH. This indicates that the increase of quanta secretion asynchronity in the presence CCH. 10 mkmol/l NA decreased the mediator release asynchronity: P90 was reduced by 28% from the initial value without changing of quantal content of the EPC. The effect of NA on the time course secretion was rather higher under the decrease of temperature and Ca2+ concentration. The multiquantal EPC were reconstructed by mathematic modelling from experimental probability secretion and amplitude-time parameters of one-quantal EPC. It was shown that the amplitude of the multiquantal EPC reduced by 14% only through the raise of the quanta secreteion asynchronity under CCH, but synchronization of the mediator quanta release by NA increased the EPC amplitude by 16%. The data obtained show that the change of the time course of the evoked mediator secretion is the essential component of the presynaptic effects of the biologically active drugs. (RFFR 96-04-49608).
