Abstract
Purpose :
To investigate whether the novel type of multiterminal en plaque motor endplates were present in the extraocular muscles (EOMs) of other animal species. We have described a novel type of multiterminal en plaque motor endplates in the human EOMs, consisting of several large en plaque motor endings along a segment of a single myofiber. Data are lacking regarding the possible existence of this novel type of motor endplates in the EOMs of other species.
Methods :
The EOMs of four mice were rapidly frozen, processed for immunofluorescence with antibodies against Neurofilament protein 70KD, Synaptophysin, Apha-bungarotoxin and Obscurin and studied with confocal microscopy. Rabbit EOMs were processed as above. The EOMs of adult zebrafish were fixed in situ, subsequently dissected, labelled with Alpha-bungarotoxin and studied with confocal microscopy.
Results :
Multiterminal en plaque motor endplates were present in individual myofibers, in the motor endplate zone of the EOMs of mice, although we cannot say yet whether they were polyinnervated or multiple innervated. Results on the rabbit EOMs are under collection. The EOMs of zebrafish displayed multiterminal en plaque motor endplates in myofibers found both in the orbital and global layers.
Conclusions :
Multiterminal en plaque motor endplates exist in the myofibers of the EOMs of other common animal species and are not only a particular feature of human EOMs. More experiments are needed to clarify whether they are polyinnervated.
This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.