PMID- 11038408
OWN - NLM
STAT- MEDLINE
DCOM- 20001116
LR  - 20151119
IS  - 0958-0670 (Print)
IS  - 0958-0670 (Linking)
VI  - 85
IP  - 5
DP  - 2000 Sep
TI  - Selective long-term electrical stimulation of fast glycolytic fibres increases 
      capillary supply but not oxidative enzyme activity in rat skeletal muscles.
PG  - 567-73
AB  - Glycolytic fibres in rat extensor digitorum longus (EDL) and tibialis anterior 
      (TA) were selectively activated, as demonstrated by glycogen depletion, by 
      indirect electrical stimulation via electrodes implanted in the vicinity of the 
      peroneal nerve using high frequency (40 Hz) trains (250 ms at 1 Hz) and low 
      voltage (threshold of palpable contractions). This regime was applied 10 times 
      per day, each bout being of 15 min duration with 60 min recovery, for 2 weeks. 
      Cryostat sections of muscles were stained for alkaline phosphatase to depict 
      capillaries, succinate dehydrogenase (SDH) to demonstrate oxidative fibres, and 
      periodic acid-Schiff reagent (PAS) to verify glycogen depletion. Specific 
      activity of hexokinase (HK), 6-phosphofructokinase, pyruvate kinase, glycogen 
      phosphorylase and cytochrome c oxidase (COX) were estimated separately in 
      homogenates of the EDL and the predominantly glycolytic cortex and oxidative core 
      of the TA. Stimulation increased the activity of HK but not that of oxidative 
      enzymes in fast muscles. Comparison of changes in oxidative capacity and 
      capillary supply showed a dissociation in the predominantly glycolytic TA cortex. 
      Here, COX was 3.9+/-0.68 microM min(-1) (g wet wt)-1 in stimulated muscles 
      compared with 3.7+/-0.52 microM min(-1) (g wet wt)-1 in contralateral muscles 
      (difference not significant), while the percentage of oxidative fibres (those 
      positively stained for SDH) was also similar in stimulated (14.0+/-2.8 %) and 
      contralateral (12.2 +/-1.9 %) muscles. In contrast, the capillary to fibre ratio 
      was significantly increased (2.01+/-0.12 vs. 1.55+/-0.04, P<0.01). We conclude 
      that capillary supply can be increased independently of oxidative capacity, 
      possibly due to haemodynamic factors, and serves metabolite removal to a greater 
      extent than substrate delivery.
FAU - Egginton, S
AU  - Egginton S
AD  - Angiogenesis Research Group, Department of Physiology, University of Birmingham, 
      Birmingham B15 2TT, UK. s.egginton@bham.ac.uk
FAU - Hudlicka, O
AU  - Hudlicka O
LA  - eng
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
PL  - England
TA  - Exp Physiol
JT  - Experimental physiology
JID - 9002940
RN  - 0 (Biomarkers)
RN  - 9005-79-2 (Glycogen)
RN  - EC 1.9.3.1 (Electron Transport Complex IV)
RN  - EC 2.4.1.- (Phosphorylases)
RN  - EC 2.7.1.1 (Hexokinase)
RN  - EC 2.7.1.11 (Phosphofructokinase-1)
RN  - EC 2.7.1.40 (Pyruvate Kinase)
RN  - S88TT14065 (Oxygen)
SB  - IM
MH  - Animals
MH  - Biomarkers/analysis
MH  - Capillaries/metabolism/*physiology
MH  - Electric Stimulation
MH  - Electron Transport Complex IV/metabolism
MH  - Glycogen/*metabolism
MH  - Hexokinase/metabolism
MH  - Hindlimb/physiology
MH  - Histocytochemistry
MH  - Male
MH  - Muscle Contraction/physiology
MH  - Muscle Fibers, Fast-Twitch/*enzymology/*metabolism
MH  - Muscle, Skeletal/*blood supply/*enzymology/metabolism
MH  - Neovascularization, Physiologic
MH  - Oxygen/metabolism
MH  - Phosphofructokinase-1/metabolism
MH  - Phosphorylases/metabolism
MH  - Pyruvate Kinase/metabolism
MH  - Rats
MH  - Rats, Sprague-Dawley
EDAT- 2000/10/20 11:00
MHDA- 2001/02/28 10:01
CRDT- 2000/10/20 11:00
PHST- 2000/10/20 11:00 [pubmed]
PHST- 2001/02/28 10:01 [medline]
PHST- 2000/10/20 11:00 [entrez]
AID - PHY_2028 [pii]
PST - ppublish
SO  - Exp Physiol. 2000 Sep;85(5):567-73.