Afferent-inherent regulation of myosin heavy chain isoforms in rat muscle spindles.

Afferent-inherent regulation of myosin heavy chain isoforms in rat muscle spindles.

Walro J M; Wang J; Story G M

Muscle & nerve

1997

1997-12

Whether afferents exert their morphogenetic influence on spindles through release of trophic factors at intrafusal fiber junctions or via participation in proprioceptive pathways which modulate the motor activity to muscles was investigated by comparing myosin heavy chain (MHC) expression in intrafusal fibers after ablation of afferents (deafferentation, or DA) to the extensor digitorum longus (EDL) of adult rats or after ablation of the corresponding central processes of afferents to the spinal cord (central-process ablation, or CPA). DA and CPA elicited an exaggerated pedal plantarflexion, and hypertrophy of the EDL concomitant with atrophy of the soleus in the affected hindlimb. Frequencies and patterns of expression of seven MHCs expressed by intrafusal fibers in CPA muscles were indistinguishable from normal rats. However, frequencies and patterns of expression of several MHCs were abnormal following DA. Thus factors transported anterogradely from afferents to intrafusal fibers may regulate MHC expression in intrafusal fibers.

Afferent Pathways/physiology; Afferent/*physiology; Animals; Denervation; Female; Ganglia; Ganglionectomy; Isomerism; Muscle Spindles/*metabolism; Myosin Heavy Chains/*metabolism; Neurons; Rats; Spinal Cord/physiology; Spinal/physiology; Sprague-Dawley; Toes/innervation

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

1549–1560

12

20