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Updated: Jul 3, 2025

Assessment of Long-term Depression Induction in Adult Cerebellar Slices
Published on: October 16, 2019
Mechanism of post-tetanic depression of slow muscle fibres
1Discipline of Physiology, School of Medical Sciences, Faculty of Medicine and Health, The University of Sydney, Sydney, NSW, 2006, Australia. joeh@iinet.net.au.
Abstract:
A brief tetanic stimulation has a very different effect on the subsequent isometric twitch force of fast and slow skeletal muscles. Fast muscle responds with an enhanced twitch force which doubles that of the pre-tetanic value, whereas slow muscle depresses the post-tetanic twitch by about 20%. Twitch potentiation of fast muscle has long been known to be due to myosin light chain 2 phosphorylation. It is proposed that post-tetanic twitch depression in slow muscle is due to the dephosphorylation of the slow isoform of the thick filament protein, myosin-binding protein-C, by Ca2+/calmodulin-activated phosphatase calcineurin, whilst its phosphorylation underlies the force enhancement due to β-adrenergic stimulation in slow and fast muscle.
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