Molecular Characteristics Suggest an Effector Function of Palisade Endings in Extraocular Muscles

Abstract

This study provides evidence that palisade endings in cat EOMs have effector function. The findings may be of significance for strabismus surgery because palisade endings are also found in human EOMs.

Proprioception in the Extraocular Muscles of Mammals and Man

“…We could show that ChAT-positive nerve fibers form palisade endings and that the palisade complex is ChAT-positive too (Konakci et al, 2005). Neuromuscular contacts, if present in palisade endings, bind α-bungarotoxin as well (Konakci et al, 2005). Thus, our new results show that palisade endings exhibit molecular characteristics of effector organs (Konakci et al, 2005).…”

“…These structures are considered to be proprioceptors (Buisseret, 1995;Donaldson, 2000;Ruskell, 1999). We could show that ChAT-positive nerve fibers form palisade endings and that the palisade complex is ChAT-positive too (Konakci et al, 2005). Neuromuscular contacts, if present in palisade endings, bind α-bungarotoxin as well (Konakci et al, 2005).…”

“…Palisade endings were analyzed in cat EOMs using antibodies against choline acetyltranferase (ChAT) and α-bungarotoxin (Konakci et al, 2005). ChAT is a marker for cholinergic neurons in the nervous system, while α-bungarotoxin labels postsynaptic acetylcholinergic receptors.…”

“…Recently, we analyzed the molecular characteristics of palisade endings. All these data are published elsewhere (Blumer et al, 1998(Blumer et al, , 1999(Blumer et al, , 2001a(Blumer et al, and b, 2003Konakci et al, 2005;Lukas et al, 1994Lukas et al, , 1997Lukas et al, , 2000. In the present article we refer to muscle spindles in human EOMs, Golgi tendon organs in the EOMs of even-toed ungulates (pig, calf and sheep) and palisade endings in cat EOMs.…”

How does the structure of extraocular muscles and their nerves affect their function?

“…In later studies of other species, the same authors ascertained that the structures in question are pure cholinergic motor organs arising from axons that also supply the associated MIF. [27][28][29][30] They hence argued, in contrast to previous studies, 31 that surgical strabismus procedures should have no side effects with respect to eye-position signals. 30 Other studies, using central tracer injections in non-human primates, also support a motor function, but suggest that tendon endings and 'en grappe' terminals arise from separate neurons located around the periphery of the motor nuclei of EOMs.…”