The muscle spindle is invested by a capsule of continuous, multilayered perineural epithelium, creating a periaxial space around the intrafusal muscle fibres and their innervation. The ultrastructural permeability of the muscle spindle capsule was assessed in anterior tibialis muscles of adult mice after systemic injection of the exogenous protein tracer, horseradish peroxidase (HRP). After varying time intervals ranging from 2 to 240 minutes, anesthetized animals were systemically perfused with fixative. Muscles were then removed and processed by routine cytochemical methods in order to demonstrate the distribution of peroxidase activity. While bare capillaries were never encountered within the intracapsular periaxial space of the muscle spindle, they frequently and intimately abut against its outer perineural capsule. Two minutes after injection of HRP, reaction product was localized in capillary endothelial plasmalemmal vesicles, just prior to its accumulation in the tissue space immediately surrounding the subjacent capsular perineurium in the equatorial region. In the polar region of the muscle spindle capsule, however, there was evidence of reaction product in the periaxial space at the same two minute time period. Ten minutes after administration of the tracer, a small population of perineural vesicles contained HRP. At the 12.5 minute interval, the sarcolemmae and T-tubules of polar intrafusal muscle fibres were subsequently labelled. Equatorial (sensory) regions of muscle spindles appeared to be relatively less permeable to the entrance of the tracer than more distal polar regions. By 15 minutes post-injection, HRP was seen traversing the perineural capsule in equatorial zones; and by 30 minutes, perineural and Schwann cell phagocytosis of the exogenous protein was extensive. / Medicine, Faculty of / Cellular and Physiological Sciences, Department of / Graduate
| Identifer | oai:union.ndltd.org:UBC/oai:circle.library.ubc.ca:2429/21070 |
| Date | January 1978 |
| Creators | Dow, Pierre Roger |
| Source Sets | University of British Columbia |
| Language | English |
| Detected Language | English |
| Type | Text, Thesis/Dissertation |
| Rights | For non-commercial purposes only, such as research, private study and education. Additional conditions apply, see Terms of Use https://open.library.ubc.ca/terms_of_use. |
Page generated in 0.002 seconds