Short-term effects of prednisolone on neuromuscular transmission in the isolated mdx mouse diaphragm.
To determine the mechanism of the beneficial effects of prednisolone on Duchenne muscular dystrophy (DMD), we examined the short-term effects of prednisolone on neuromuscular transmission by using conventional microelectrode methods in the mdx mice. High (56 micromol/liter) and low (2.8 micromol/liter) concentrations of prednisolone were applied to a bath containing phrenic nerve-diaphragm preparations from mdx mice, and several parameters related to neuromuscular transmission were recorded. The high dose of prednisolone significantly decreased parameter n on quantal release by nerve impulse and decay time-constant of end-plate potentials, which showed adverse effect on neuromuscular transmission. The low dose of prednisolone did not significantly increase quantal content, but could assist the compensatory reaction to maintain the safety margin of neuromuscular transmission in the mdx mice. Our results suggest that the latter effect represents one of the possible mechanisms of the therapeutic effects of prednisolone on DMD.
Department of Neurology, Kawatana National Hospital, Nagasaki 859-3615, Japan [corrected]
T
T
Fukudome
N
N
Shibuya
T
T
Yoshimura
K
K
Eguchi
D000818:Animals; D000893:Anti-Inflammatory Agents / Q000494:pharmacology*; D003964:Diaphragm / Q000294:innervation; D004594:Electrophysiology; D019706:Excitatory Postsynaptic Potentials / Q000187:drug effects* / Q000502:physiology; D005260:Female; D006801:Humans; D066298:In Vitro Techniques; D051379:Mice; D018101:Mice, Inbred mdx; D008839:Microelectrodes; D020388:Muscular Dystrophy, Duchenne / Q000503:physiopathology; D009469:Neuromuscular Junction / Q000187:drug effects* / Q000502:physiology; D010791:Phrenic Nerve / Q000187:drug effects* / Q000502:physiology; D011239:Prednisolone / Q000494:pharmacology*; D009435:Synaptic Transmission / Q000187:drug effects*; D013997:Time Factors
D000893:Anti-Inflammatory Agents; D011239:Prednisolone