Role of carbonic anhydrase in urinary acidification by the toad bladder

Tw, Ziegler; Ludens, JH; Dd, Fanestil

doi:10.1152/ajplegacy.1974.227.5.1132

Cited by 17 publications

(6 citation statements)

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“…Acetazolamide has been shown to inhibit acidification when the bathing media contain low tensions of CO2 [10,16]. Moreover, this inhibitory effect may be partially overcome by increasing the supply of CO2 to the bladder [10,30]. In the present study, in which pH stat measurements were made in the Ussing chamber, the rate of acidification was greater in the presence of exogenous COs than with endogenous CO2 alone.…”

Section: Discussionmentioning

confidence: 51%

Urinary acidification and carbonic anhydrase distribution in bladders of Dominican and Colombian toads

1974

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Summary.A comparative analysis of the acidifying capacity and distribution of carbonic anhydrase was made in isolated bladders of toads, Bufo marinus, obtained from the Dominican Republic (D) and Colombia (C). In the absence of exogenous CO2 and HCOS-, mucosal acidification was observed in 10 of the 18 C toad bladders examined and in only one of 18 D toad bladders. In approximately half of the C toad bladders the rate of acidification was measurable by means of the pH stat method; the average rate in this group was 0.22 + 0.03 lamoles/hour in the absence of exogenous COz and 0.35 _+ 0.04 lamoles/hour in the presence of 1% CO2. Rates were not measurable in D toad bladders with or without CO 2. Staining of whole stretched bladders for carbonic anhydrase revealed a population of enzyme-containing mucosal cells accounting for 4.6 % of the surface area in C toad bladders and 0.8 % in D toad bladders. Electron histochemistry of both bladders identified the carbonic anhydrase-containing cells as mitochondria-rich cells.Conflicting observations on the acidifying ability of the urinary bladder of the toad, Bufo marinus, have been attributed to the different geographical origin of the toads studied [16]. Whereas Leaf and coworkers [14,15]

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Section: Discussionmentioning

confidence: 51%

Urinary acidification and carbonic anhydrase distribution in bladders of Dominican and Colombian toads

1974

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“…Carbonic anhydrase activity was greater in each band of separated cells prepared from Colombian toads than in cells in the corresponding band prepared from Dominican toads (Table 3), in contrast to the previous report of similar activity in separated cells from toads of the two origins [21]. It has been suggested that the difference in carbonic anhydrase activity is related to the ability to acidify urine [18,25]. …”

Section: Assaymentioning

confidence: 58%

“…Using histochemical techniques [19] and enzymatic assay of the entire epithelial cell population [25], it has been found that carbonic anhydrase activity is greater in epithelial cells of urinary bladders of Colombian toads than of Dominican toads. Carbonic anhydrase activity was greater in each band of separated cells prepared from Colombian toads than in cells in the corresponding band prepared from Dominican toads (Table 3), in contrast to the previous report of similar activity in separated cells from toads of the two origins [21].…”

Section: Assaymentioning

confidence: 99%

Study of enzymes regulating vasopressin-stimulated cyclic AMP metabolism in separated mitochondria-rich and granular epithelial cells of toad urinary bladder

Handler

Preston

1976

J. Membrain Biol.

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The epithelial cells of the toad urinary bladder are morphologically heterogenous. In order to relate the effect of vasopressin on cyclic AMP metabolism to cell type, the epithelial cells were separated by the density gradient technique of Scott, Sapirstein and Yoder (Science 184:797, 1974). The separation was verified by electron-microscopy and by observing that the band of cells enriched in mitochondria-rich cells was enriched in carbonic anhydrase activity compared to the band of granular cells. A large portion of cells collected from the gradient was considered to be nonviable, precluding further study of their function as intact cells. Vasopressin-stimulated adenylate cyclase activity in homogenates of granular cells was simular to that in homogenates of mitochondria-rich cells. Cyclic nucleotide phosphodiesterase activity was also similar in the two types of cell. Thus, the enzymes known to be involved in cyclic AMP metabolism in response to vasopressin appear to be located in both major cell types.

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“…Proton flux (JH) was measured on Colombian toad bladder (Ludens & Fanestil, 1972); in order to stimulate this transport, toads were rendered acidotic by keeping them in a solution of NH4Cl, for 3 days (Ziegler, Ludens & Fanestil, 1974); incubation was conducted in a medium of the following composition (mM): NaCl, 110; KCl, 3-5; Na2HPO4, 2; CaCl2, 1; glucose, 10.…”

Section: Introductionmentioning

confidence: 99%

Effects of vanadate on the functional properties of the isolated toad bladder.

Beauwens¹,

Crabbé²,

Rentmeesters³

1981

The Journal of Physiology

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SUMMARY1. Vanadate, considered by some as a candidate for physiological modulation of Na pumping activity, was studied in the isolated toad urinary bladder. It produced a decrease in Na transport activity that was reversible and could be partially antagonized by pretreatment with a disulphonic distilbene derivative, SITS. This suggests an intracytoplasmic site of action for vanadate. Other transition metal salts, prepared from Ta and Nb, produced instead a transient rise in Na transport and this was unaffected by SITS.2. Comparison between ouabain and vanadate showed clear-cut differences: inhibition of Na transport by the former, not the latter, was partially overcome by increasing cell Na or serosal K. Unexpectedly intracellular K did not decrease appreciably following vanadate treatment, in contrast to what occurs when ouabain was used instead.3. Vasopressin-induced hydro-osmotic flow was irreversibly inhibited by vanadate but not by ouabain; pretreatment with SITS attenuated this effect. Moreover, vanadate blocked urinary acidification in this epithelium, thus supporting the hypothesis that proton flow occurs through an enzyme distinct from the mitochondrial ATPase, insensitive to vanadate.

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Role of carbonic anhydrase in urinary acidification by the toad bladder

Cited by 17 publications

References 0 publications

Urinary acidification and carbonic anhydrase distribution in bladders of Dominican and Colombian toads

Urinary acidification and carbonic anhydrase distribution in bladders of Dominican and Colombian toads

Study of enzymes regulating vasopressin-stimulated cyclic AMP metabolism in separated mitochondria-rich and granular epithelial cells of toad urinary bladder

Effects of vanadate on the functional properties of the isolated toad bladder.

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