Ten days of urinary outlet obstruction in the rat induced a threefold increase in bladder weight. Active force of control and hypertrophic bladder muscle strips was measured at varying PO2 levels after high-K+, carbachol, or electrical field stimulation. Highest force output was obtained with carbachol. Force per muscle area was lower in the hypertrophic muscles. The basal rates of oxygen consumption and lactate formation were similar in the two groups. The metabolic tension cost (ATP turnover/active force) was similar in the two groups for activation with high K+ and carbachol. In anoxia the active force decreased, but this was less pronounced in the hypertrophied muscle. Hypertrophied muscle could, in contrast to the controls, maintain a sustained K+ contracture in anoxia. Basal metabolic rates and tension cost were markedly reduced in anoxia for both groups. The lower force per area with unaltered tension cost, in hypertrophic muscles under all experimental conditions, may reflect unaltered intrinsic properties of the contractile system, although the amount of contractile material has decreased relative to cell volume. The increased resistance to anoxia may reflect a metabolic adaptation to impaired oxygen supply to the hypertrophied tissue.
Malmqvist, Ulf,Lunds universitet, Lund University, Medicinska fakulteten, Faculty of Medicine, Institutionen för laboratoriemedicin, Department of Laboratory Medicine, Avdelningen för klinisk kemi och farmakologi, Division of Clinical Chemistry and Pharmacology(SwePub:)
Uvelius, Bengt,Forskargrupper vid Lunds universitet, Lund University Research Groups, Lunds universitet, Lund University, Urologi, Urology(SwePub:)
Ingår i:American Journal of PhysiologyAmerican Physiological Society0002-9513258:5 Pt 1, s. 923-932