Comparison between botulinum neurotoxin type A2 and type A1 by electrophysiological study in healthy individuals.
Botulinum neurotoxin type A1 (BoNTs/A1) and type B (BoNT/B) have been used for treating hyperactive muscle contractions. In the present study, we compared the effect of botulinum neurotoxin subtype A2 (6.5 mouse LD50 units A2 neurotoxin, A2NTX) and onabotulinumtoxinA (10 mouse LD50 units BoNT/A1 product) by measuring the compound muscle action potentials (CMAPs) before and after administration. In total, 8 healthy subjects were examined in the present study. A2NTX was injected into the extensor digitorum brevis (EDB) muscle, followed by onabotulinumtoxinA injection into the contralateral EDB muscle after 16 weeks. The CMAP amplitudes from the EDB, abductor hallucis (AH), and abductor digiti minimi pedis (ADM) muscles were measured after each BoNT injection on days 1, 3, 7, 14, 28, 56, 84, and 112 to assess the effect of the toxin. On day 14, both A2NTX and onabotulinumtoxinA produced an approximately 70% decline in EDB CMAP amplitude compared to the baseline values; significant reduction of the CMAP continued through day 112. The CMAP amplitudes from neighboring muscles (AH and ADM) remained intact throughout the study period, except for a slight but significant drop at day 28 after onabotulinumtoxinA injection compared to A2NTX. The current findings indicate that small doses (6.5 units and 10 units) of A2NTX and onabotulinumtoxinA have at least comparable onset and duration of action, although similar clinical effects were obtained with lower dose using A2NTX.
Department of Clinical Neuroscience, Institute of Health Biosciences, Graduate School of Medicine, University of Tokushima, 18-15 Kuramoto-cho, Tokushima-shi, Tokushima 770-8503, Japan; Department of Neurology, National Center Hospital of Neurology and Psychiatry, 4-1-1 Ogawa-Higashi, Kodaira-shi, Tokyo 187-8551, Japan. Electronic address: ymukai@ncnp.go.jp.
Yohei
Y
Mukai
Department of Clinical Neuroscience, Institute of Health Biosciences, Graduate School of Medicine, University of Tokushima, 18-15 Kuramoto-cho, Tokushima-shi, Tokushima 770-8503, Japan.
Yoshimitsu
Y
Shimatani
Department of Clinical Neuroscience, Institute of Health Biosciences, Graduate School of Medicine, University of Tokushima, 18-15 Kuramoto-cho, Tokushima-shi, Tokushima 770-8503, Japan.
Wataru
W
Sako
Department of Clinical Neuroscience, Institute of Health Biosciences, Graduate School of Medicine, University of Tokushima, 18-15 Kuramoto-cho, Tokushima-shi, Tokushima 770-8503, Japan.
Kotaro
K
Asanuma
Department of Clinical Neuroscience, Institute of Health Biosciences, Graduate School of Medicine, University of Tokushima, 18-15 Kuramoto-cho, Tokushima-shi, Tokushima 770-8503, Japan.
Hiroyuki
H
Nodera
Department of Neurology, National Center Hospital of Neurology and Psychiatry, 4-1-1 Ogawa-Higashi, Kodaira-shi, Tokyo 187-8551, Japan.
Takashi
T
Sakamoto
Department of Clinical Neuroscience, Institute of Health Biosciences, Graduate School of Medicine, University of Tokushima, 18-15 Kuramoto-cho, Tokushima-shi, Tokushima 770-8503, Japan.
Yuishin
Y
Izumi
Department of Veterinary Sciences, School of Life and Environmental Sciences, Osaka Prefecture University, 1-18 Rinku-oraikita, Izumisano-shi, Osaka 599-8531, Japan.
Tomoko
T
Kohda
Department of Veterinary Sciences, School of Life and Environmental Sciences, Osaka Prefecture University, 1-18 Rinku-oraikita, Izumisano-shi, Osaka 599-8531, Japan.
Shunji
S
Kozaki
Department of Clinical Neuroscience, Institute of Health Biosciences, Graduate School of Medicine, University of Tokushima, 18-15 Kuramoto-cho, Tokushima-shi, Tokushima 770-8503, Japan.
Ryuji
R
Kaji
D019274:Botulinum Toxins, Type A / Q000008:administration & dosage / Q000494:pharmacology*; D004594:Electrophysiology; D006801:Humans; D007273:Injections, Intramuscular; D009119:Muscle Contraction / Q000187:drug effects; D053580:Muscle Strength / Q000187:drug effects; D018482:Muscle, Skeletal / Q000187:drug effects
D019274:Botulinum Toxins, Type A
A2NTX; Botulinum neurotoxin; CMAP; EDB test