Faculty Collaboration Database

Fatigability and blood flow in the rat gastrocnemius-plantaris-soleus after hindlimb suspension. J Appl Physiol (1985) 1992 Sep;73(3):1135-40

Date

09/01/1992

Pubmed ID

1400027

DOI

10.1152/jappl.1992.73.3.1135

Scopus ID

2-s2.0-0026700241 (requires institutional sign-in at Scopus site)   48 Citations

Abstract

The purpose of this study was to test the hypothesis that hindlimb suspension increases the fatigability of the soleus during intense contractile activity and determine whether the increased fatigue is associated with a reduced muscle blood flow. Cage-control (C) and 15-day hindlimb-suspended (HS) rats were anesthetized, and either the gastrocnemius-plantaris-soleus (G-P-S) muscle group or the soleus was stimulated (100 Hz, 100-ms trains at 120/min) for 10 min in situ. In the G-P-S preparation, blood flow was measured with radiolabeled microspheres before and at 2 and 10 min of contractile activity. The G-P-S fatigued markedly at this stimulation frequency, and the differences between C and HS animals were not significant until the 9th min of contractile activity. In contrast, the stimulation resulted in faster rates and significantly larger amounts of fatigue in the soleus from HS than from C animals. The atrophied soleus showed significant differences by 1 min of stimulation (C = 70 +/- 1% vs. HS = 57 +/- 2% of peak train force) and remained different at 10 min (C = 64 +/- 4% vs. HS = 45 +/- 2% peak train force). Relative blood flow to the soleus was similar between groups before and during contractile activity (rest: C = 20 +/- 3 vs. HS = 12 +/- 3; 2 min: C = 128 +/- 6 vs. HS = 118 +/- 4; 10 min: C = 123 +/- 11 vs. HS = 105 +/- 11 ml.min-1.100 g-1). In conclusion, these results established that 15 days of HS increased the fatigability of the soleus, but the effect was not caused by a reduced muscle blood flow.

Author List

McDonald KS, Delp MD, Fitts RH

Author

Robert Fitts PhD Professor in the Biological Sciences department at Marquette University

MESH terms used to index this publication - Major topics in bold

Animals
Fatigue
Hindlimb
Immobilization
Male
Muscle Contraction
Muscles
Muscular Atrophy
Rats
Rats, Sprague-Dawley
Regional Blood Flow
Weightlessness