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New evidence for a presynaptic action of prednisolone at neuromuscular junctions
Author(s) -
Dal Belo Cháriston André,
Leite Gildo Bernardo,
Fontana Marcos Dias,
Corrado Alexandre Pinto,
Zanandréa Baso Ana Cristina,
Moreno Serra Carmen Sílvia,
Oliveira Antonio Carlos,
RodriguesSimioni Léa
Publication year - 2002
Publication title -
muscle and nerve
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.025
H-Index - 145
eISSN - 1097-4598
pISSN - 0148-639X
DOI - 10.1002/mus.10132
Subject(s) - prednisolone , neuromuscular junction , phrenic nerve , sciatic nerve , endocrinology , compound muscle action potential , diaphragm (acoustics) , medicine , neuromuscular blockade , neuromuscular transmission , chemistry , tibialis anterior muscle , anesthesia , electrophysiology , pharmacology , skeletal muscle , biology , respiratory system , neuroscience , physics , acoustics , loudspeaker
The action of prednisolone at the neuromuscular junction was studied in mouse isolated phrenic nerve–diaphragm and rat external popliteal/sciatic nerve–tibialis anterior muscle preparations. Prednisolone (0.03 mM and 0.3 mM) did not alter the twitch‐tension in phrenic nerve–diaphragm preparations after 120 min, but increased the frequency (170 ± 4%) and amplitude (200 ± 13%) of miniature end‐plate potentials. Quantal content was not influenced by the glucocorticoid treatment. Prednisolone (400 μg/kg) did not change the twitch‐tension in rat external popliteal/sciatic nerve–tibialis anterior muscle preparations. However, this steroid (0.3 mM) prevented the neuromuscular blockade by d‐tubocurarine (1.45 μM) in mouse preparations by 70 ± 10% ( P < 0.05). A similar effect (82 ± 6% protection, P < 0.05) occurred in rats treated with prednisolone (400 μg/kg) before d‐tubocurarine (225 μg/kg). In phrenic nerve–diaphragm preparations, prednisolone (0.3 mM) increased (13 ± 4%, p < 0.05) the twitch‐tension in the presence of β‐bungarotoxin (1 μM), and prevented the blockade produced by this toxin (0.15 μM) in its third phase of action. This presynaptic facilitatory effect may contribute to the usefulness of prednisolone in myasthenia gravis. © 2002 Wiley Periodicals, Inc. © 2002 Wiley Periodicals, Inc. Muscle Nerve 26: 37‐43, 2002