Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0403608 (ureter)
 9,655 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The effect of metabolic inhibition on the contractile function of adult guinea-pig ureter has been investigated. Strips of ureteric smooth muscle were loaded with Indo-1 or SNARF to measure intracellular [Ca2+] ([Ca2+]i) or pH (pHi) simultaneously with force. Inhibiting oxidative phosphorylation with cyanide rapidly reduced phasic contractions and the associated Ca2+ transients, after initial transient increases. The effects of cyanide were reversible and related to the amount of contractile activity undertaken. Inhibition of glycolysis with iodoacetate abolished all force. In high-K+-depolarised preparations, cyanide reduced the tonic contraction, but this was not accompanied by a reduction in [Ca2+]i, suggesting a desensitisation of the myofilaments. Cyanide produced a fall in pHi, which may underlie the initial transient increase in force. These data suggest that metabolic inhibition reduces force in the ureter by affecting both excitation and hence the Ca2+ transient, and at the myofilaments to reduce their sensitivity to Ca2+. Thus when oxidative metabolism is impaired contractile dysfunction may arise in the ureter.
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PMID:The effects of metabolic inhibition on force, Ca2+ and pHi in guinea-pig ureteric smooth muscle. 938 37

The effect of inhibiting oxidative phosphorylation on electrically stimulated phasic and high-K+ depolarization-induced tonic contractions in ureteric smooth muscle has been investigated. Intracellular [Ca2+] and pH were monitored fluorimetrically with simultaneous tension measurement, in adult and neonatal rat and guinea-pig ureter. Little difference was found in the response of adult or neonatal rat ureters; cyanide abolished phasic contractions and intracellular Ca2+ transients. The contractions of the adult guinea-pig ureter were also reduced by cyanide, but not as much as those of the adult rat. Neonatal guinea-pig was, however, remarkably resistant to the effects of cyanide, with force and Ca2+ transients remaining at control levels after an initial transient dip. These differences between tissues were not apparent when a high K+ concentration was used to depolarize tissues and produce maintained [Ca2+]i and force changes; cyanide reduced force but not [Ca2+]i in all preparations. Intracellular pH decreased in all preparations with inhibition of oxidative phosphorylation, but this did not correlate with changes in contraction. It is concluded that there are both species and developmental differences in the response to metabolic inhibition of the ureter which lead to differing changes in contractile activity.
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PMID:Developmental and species differences in the response of the ureter to metabolic inhibition. 964 28