title: Measurement of tissue volume during non-steady state high-intensity muscle contraction.
abstract: To investigate the pressures driving water into stimulated muscle, water distribution during and after muscle stimulation was studied in isolated cat muscles perfused by recirculating diluted blood. 51Cr-labeled EDTA (51Cr-EDTA) and Evans blue-labeled albumin were used to determine extracellular volume and plasma volume (PV), respectively. Change in tissue volume was calculated as -PV. Interstitial volume (IFV) was determined from the ratio of interstitial solute (51Cr-EDTA and sodium) mass and interstitial concentration. Interstitial mass was determined by mass balance, and interstitial concentration was determined from solute flux and Fick's Law. One group was stimulated at 4 Hz for 2 min, and a second was stimulated by 80-Hz trains (1 train/s, 0.1 s duration). Four Hertz stimulation increased total tissue volume by approximately 3 ml/100 g and decreased IFV by 1 ml/100 g. Train stimulation increased total tissue volume by 6 ml/100 g and decreased IFV by 4. These data indicate that water moves into cells faster than the simultaneous transcapillary flow, suggesting that intracellular osmoles provide the primary driving pressure in stimulation-induced swelling.
authors.affiliation: Department of Exercise Science, University of South Carolina, Columbia 29208, USA.
authors.forename: D S
authors.initials: DS
authors.lastname: Ward
authors.forename: M T
authors.initials: MT
authors.lastname: Hamilton
authors.forename: P D
authors.initials: PD
authors.lastname: Watson
mesh_terms: D000818:Animals; D001810:Blood Volume; D001834:Body Water / Q000378:metabolism*; D002415:Cats; D004558:Electric Stimulation / Q000379:methods; D005110:Extracellular Space / Q000378:metabolism; D006614:Hindlimb; D066298:In Vitro Techniques; D008954:Models, Biological; D009119:Muscle Contraction; D018482:Muscle, Skeletal / Q000098:blood supply / Q000378:metabolism* / Q000502:physiology*; D014018:Tissue Distribution