Activity-dependent degeneration of axotomized neuromuscular synapses in Wld S mice.
Bottom Line: Periodic high-frequency nerve stimulation (100 Hz: 1s/100s) reduced synaptic protection in Wld(S) preparations by about 50%.This effect was abolished in reduced Ca(2+) solutions.Together, the data suggest that vulnerability of mature neuromuscular synapses to axotomy, a potent neurodegenerative trigger, may be enhanced bimodally, either by disuse or by hyperactivity.
Affiliation: Euan MacDonald Centre for Motor Neurone Disease Research, Hugh Robson Building, University of Edinburgh, George Square, Edinburgh EH8 9XD, UK.Show MeSH
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Mentions: We found no significant effect of TTX block on FDB muscle fiber resting membrane potential (TTX-blocked; −67.33 ± 2.38 mV, n = 5; saline control: −71.59 ± 2.38 mV, n = 3; P > 0.05, t-test). FDB muscles from WldS mice without conditioning nerve block showed a mean MEPP amplitude of 1.08 ± 0.12 mV (n = 5; Fig. 9A). Seven days of nerve block caused a significant, approximately 50% increase in MEPP amplitude (1.58 ± 0.12 mV, n = 9). However, this increase was less than that observed 7 days after complete axotomy (2.55 ± 0.47 mV, n = 3 respectively, P < 0.01 ANOVA; Bonferroni post hoc; compared with Ribchester et al., 1995).
Affiliation: Euan MacDonald Centre for Motor Neurone Disease Research, Hugh Robson Building, University of Edinburgh, George Square, Edinburgh EH8 9XD, UK.