The gamma-subunit of the acetylcholine receptor is not expressed in the levator palpebrae superioris.
In extraocular muscle (EOM), expression of the gamma-subunit, which is associated with the fetal-type acetylcholine receptor (AChR), may offer a differential target for immune-mediated damage and could explain the preponderance of ocular manifestations caused by myasthenia gravis (MG). Using Poly(A)+ RNA hybridization, we investigated expression of the gamma-subunit in bovine levator palpebrae superioris (LP), a muscle also differentially involved by MG. There were no transcripts of the gamma-subunit of the AChR, but the epsilon-subunit, associated with the adult-type AChR, was present. The results indicate that the susceptibility of LP to MG is not mediated by gamma-subunit expression and suggest that multiterminal fibers in EOM may be the site of gamma-subunit expression.
Kaminski
H J
HJ
Department of Neurology, Case Western Reserve University School of Medicine, OH 44106.
Kusner
L L
LL
Nash
K V
KV
Ruff
R L
RL
D000818:Animals; D002417:Cattle; D015870:Gene Expression; D009801:Oculomotor Muscles / Q000378:metabolism*; D012333:RNA, Messenger / Q000032:analysis; D011950:Receptors, Cholinergic / Q000032:analysis* / Q000235:genetics
D012333:RNA, Messenger; D011950:Receptors, Cholinergic