MORPHOMETRIC ANALYSIS OF COATED VESICLES IN DEVELOPING RAT MUSCLE-SPINDLES

Title

MORPHOMETRIC ANALYSIS OF COATED VESICLES IN DEVELOPING RAT MUSCLE-SPINDLES

Creator

Stephens H; Walro J M; Kucera J

Publisher

Physiological Research

Date

1992
1992

Description

The incidence of coated vesicles under sarcolemmal surfaces of equatorial, juxtaequatorial and polar regions in developing and adult spindles of the rat soleus muscle was examined by quantitative morphometry of transverse ultrathin sections. Coated vesicles were more numerous: 1) under primary sensory endings than under other types of neuromuscular contacts; 2) under the appositional sarcolemma between neighbouring intrafusal fibres than under free surfaces of the sarcolemma; and 3) in developing than in mature spindles. Factors such as location and age of the animal often interacted to produce an additive effect on the incidence of coated vesicles. Although there was a high incidence of coated vesicles at the postsynaptic surface under sensory terminals of bag2 fibres in 18 and 19 day gestational embryonic rats, it peaked in 4 day postnatal animals. The high incidence of coated vesicles at sensory endings supports the view that coated vesicles mediate neurotrophic interactions between afferents and intrafusal fibres during the critical late gestation and early postnatal time period, as sensory axons first contact their target fibres and exert a maximal directing influence on the differentiation of intrafusal fibre types. In addition, the preferential localization of coated vesicles under appositional rather than free surfaces of developing intrafusal fibres in 0-4 day rats suggests that they play a role in the transport of active substances among intrafusal fibres exhibiting different stages of maturity.

Subject

acetylcholine-receptors; cells; coated vesicles; development; innervation; intrafusal fibers; membrane; morphometry; motor; muscle spindle; Physiology; rat

Identifier

n/a

Format

Journal Article

URL Address

n/a

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Rights

Article information provided for research and reference use only. All rights are retained by the journal listed under publisher and/or the creator(s).

Pages

173-190

Issue

3

Volume

41

Citation

Stephens H; Walro J M; Kucera J, “MORPHOMETRIC ANALYSIS OF COATED VESICLES IN DEVELOPING RAT MUSCLE-SPINDLES,” NEOMED Bibliography Database, accessed July 28, 2021, https://neomed.omeka.net/items/show/8089.

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