Botulinum-induced changes in monkey eyelid muscle. Comparison with changes seen in extraocular muscle

J. D. Porter, S. Strebeck and N. F. Capra
Department of Anatomy and Neurobiology, University of Kentucky Medical Center, Lexington 40536-0084.

Botulin type A was injected into the eyelids of adult monkeys, and structural alterations in the orbicularis oculi muscle were evaluated after survival times of 7 to 84 days. The most profound change seen at both the light- and electron-microscopic levels was nonselective atrophy of virtually all muscle fibers. Moreover, the botulin-induced blockade of neuromuscular transmission was nonspecific in producing alterations in the three orbicularis fiber types. Muscle structural changes appeared to be reversible, with no apparent long-term consequences. While sprouting of preterminal axons was noted in botulin-treated muscle, formation of collateral sprouts did not appear to be widespread. These changes contrast with the fiber type-specific, long-term alterations induced in extraocular muscle by botulin treatment. However, this differential response may be attributed to the very clear differences in fiber type composition and motor control mechanisms between eyelid and extraocular muscle groups. The efficacy of botulin treatments for strabismus and focal dystonia may then be directly related to both the anatomic fiber type composition and the functional properties of motor control systems of the injected muscle.

THIS ARTICLE HAS BEEN CITED BY OTHER ARTICLES

Identification and Characterization of Layer-Specific Differences in Extraocular Muscle M-Bands
Wiesen et al.
IOVS 2007;48:1119-1127.
ABSTRACT | FULL TEXT  

Botulinum Toxin Treatment of Extraocular Muscles in Rabbits Results in Increased Myofiber Remodeling
Ugalde et al.
IOVS 2005;46:4114-4120.
ABSTRACT | FULL TEXT  

Layer-specific differences of gene expression in extraocular muscles identified by laser-capture microscopy
Budak et al.
Physiol. Genomics 2004;20:55-65.
ABSTRACT | FULL TEXT  

The Development of Longitudinal Variation of Myosin Isoforms in the Orbital Fibers of Extraocular Muscles of Rats
Rubinstein et al.
IOVS 2004;45:3067-3072.
ABSTRACT | FULL TEXT  

Susceptibility of Ocular Tissues to Autoimmune Diseases
KAMINSKI et al.
Ann. N. Y. Acad. Sci. 2003;998:362-374.
ABSTRACT | FULL TEXT  

Differential Susceptibility of the Ocular Motor System to Disease
KAMINSKI et al.
Ann. N. Y. Acad. Sci. 2002;956:42-54.
ABSTRACT | FULL TEXT  

Long-Term Changes in Myosin Heavy Chain Composition after Botulinum Toxin A Injection into Rat Medial Rectus Muscle
Kranjc et al.
IOVS 2001;42:3158-3164.
ABSTRACT | FULL TEXT  

Functional repair of motor endplates after botulinum neurotoxin type A poisoning: Biphasic switch of synaptic activity between nerve sprouts and their parent terminals
de Paiva et al.
Proc. Natl. Acad. Sci. USA 1999;96:3200-3205.
ABSTRACT | FULL TEXT