INTRODUCTION: Alzheimer's β-amyloid peptide (βAP) is known to possess a wide range of toxic effects on neurons in vitro and in vivo; however, there is little information available regarding its impact on other excitable tissues such as skeletal muscles, which, apart from brain cells, are thought to also be targets of βAP. METHODS: Utilizing the combination of electrophysiology and myography, we investigated whether βAP also impairs the functioning of myocytes in frogs and mice. RESULTS: Although application of βAP in the range of 10(-6) to 10(-8) M induced depolarization of muscle fibers in both species, it impaired contractility in frogs but not in mice, by reducing endplate potential amplitude and increasing the threshold potential. CONCLUSIONS: Unchanged contractility in the mouse in the presence of βAP is due to a higher safety factor of neuromuscular transmission in mammals compared with amphibians. Possible clinical implications are discussed.
INTRODUCTION: Alzheimer's β-amyloid peptide (βAP) is known to possess a wide range of toxic effects on neurons in vitro and in vivo; however, there is little information available regarding its impact on other excitable tissues such as skeletal muscles, which, apart from brain cells, are thought to also be targets of βAP. METHODS: Utilizing the combination of electrophysiology and myography, we investigated whether βAP also impairs the functioning of myocytes in frogs and mice. RESULTS: Although application of βAP in the range of 10(-6) to 10(-8) M induced depolarization of muscle fibers in both species, it impaired contractility in frogs but not in mice, by reducing endplate potential amplitude and increasing the threshold potential. CONCLUSIONS: Unchanged contractility in the mouse in the presence of βAP is due to a higher safety factor of neuromuscular transmission in mammals compared with amphibians. Possible clinical implications are discussed.
Authors: Valeriy G Ostapchenko; Megan Chen; Monica S Guzman; Yu-Feng Xie; Natalie Lavine; Jue Fan; Flavio H Beraldo; Amanda C Martyn; Jillian C Belrose; Yasuo Mori; John F MacDonald; Vania F Prado; Marco A M Prado; Michael F Jackson Journal: J Neurosci Date: 2015-11-11 Impact factor: 6.167