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Acute inflammation alters the response to stretch in mouse extensor digitorum longus muscle afferents
Author(s) -
Wilkinson Katherine A.,
Hochman Shawn
Publication year - 2012
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.26.1_supplement.892.4
Subject(s) - hindlimb , muscle spindle , proprioception , inflammation , lipopolysaccharide , isometric exercise , anatomy , sensitization , chemistry , extensor digitorum longus muscle , afferent , medicine , skeletal muscle , neuroscience , biology
Inflammatory pain alters muscle spindle responses to stretch (Wenngren, et al, 1998; Ro & Capra, 2001), but the exact mechanism of sensitization is unknown. We used an in vitro mouse hindlimb muscle‐nerve preparation to study plasticity in afferent responses to ramp and hold stretches following acute inflammation (0.5 mg/kg lipopolysaccharide (LPS) 18 hrs before experiment). Following LPS, units had lower baseline firing and more units were only active during stretch (6/16 LPS vs. 3/26 control). The LPS units also displayed a significantly greater decrease in firing frequency over the 4 s stretch. Some LPS units (3/16) are likely group III/IV instead of muscle spindle afferents; they had very small responses to stretch and did not show the characteristic frequency adaptation. Overall, the acute systemic inflammatory state induced by LPS clearly alters the response profile of muscle afferents to stretch, and therefore proprioceptive signaling. Further study on these changes are planned to provide insight into underlying mechanisms, their behavioral relevance, and to identify strategies that normalize function. Supported by K12GM000680NIH/NIGMS More Division (KAW) and Pfizer (SH) .