Sex differences in <i>Necturus</i> urinary bladders

LeFevre, M. E.; Norris, J. P.; Hammer, R. F.

doi:10.1002/ar.1091870105

Cited by 6 publications

(6 citation statements)

References 16 publications

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“…The morphological descriptions reported here generally agree with and greatly extend earlier accounts given for this epithelium in Necturus maculosus by Lefevre et al (1977) and Higgins et al (1977). Using winter animals, Lefevre et al employed light microscopy (with parafin sections) and scanning electron microscopy to compare the morphology of unstretched male and female urinary bladders.…”

Section: Discussionsupporting

confidence: 91%

“…Urine samples collected from animals used in this study for morphological examination show a significantly greater sodium content in bladders from low-transporting animals than in samples collected from high-transporting animals (4.3 & 0.9 mM and 0.7 & 0.1 mM, respectively). The low sodium content of urine from high-transporting bladders is confirmed by values given in previous studies ( Table 2) that also examined animals during the winter months (Bentley, 1971; Lefevre et al, 1977;Thomas et al, 1983). The difference in urine sodium concentrations is consistent with the different transport activities of the two groups of bladders.…”

Section: Differences In Electical Parameters and Urine N A And K Concsupporting

confidence: 77%

“…To our knowledge only two short accounts are extant: Higgins et al (1977) have given a brief description of the ultrastucture, but without micrographs; Lefevre et al (1977) have described sex differences in urinary bladders using light microscopy and scanning electron microscopy.…”

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confidence: 99%

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Seasonal variations in the fine structure of the Necturus maculosus urinary bladder epithelium: Low transporters and high transporters

Karnaky¹,

Lau²,

Garretson³

et al. 1984

Am. J. Anat.

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Although the urinary bladder of Necturus maculosus provides an important model system for studying the mechanisms of active Na absorption, little critical attention has been paid to the fine structure of its epithelium. Moreover, two distinct groups of urinary bladders, low and high Na transporters, have been described based on short-circuit current or transepithelial potential difference. In the present study, over an 11-month period, stable electrical parameters (short-circuit current, transepithelial potential difference, and resistance) were recorded from 63 chamber-mounted bladders. Analysis of these parameters revealed a highly significant difference between two groups (low transporters and high transporters) occurring at different times of the year. Consistent with these data, in urine collected from the bladders, the Na concentration in low transporters was significantly higher than that in high transporters. A subpopulation of these bladders was subsequently fixed and examined at the light and/or electron microscopic level. Low-transporting bladders were characterized unequivocally by a thin, stratified squamous epithelium only 6-15 micron thick. High-transporting bladders were composed predominantly of columnar-shaped granular cells up to 70 micron in height, with ciliated, mitochondria-rich, and basal cells present in small numbers. There is thus a correlation between transport activity, as measured by electrophysiological techniques and urine sodium analysis, and the structure of the tissue. Moreover, these parameters exhibit significant seasonal variation, the underlying mechanisms of which remain obscure.

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Section: Discussionsupporting

confidence: 91%

Section: Differences In Electical Parameters and Urine N A And K Concsupporting

confidence: 77%

See 1 more Smart Citation

Seasonal variations in the fine structure of the Necturus maculosus urinary bladder epithelium: Low transporters and high transporters

Karnaky¹,

Lau²,

Garretson³

et al. 1984

Am. J. Anat.

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“…The data presented here indicate that the simple equivalent circuit model of the epithelium (Fig. 1) is inadequate ; minimum additional requirements are that Vb be partitioned into a current source representing the Na pump, that parallel emf's be added for each ionic conductance, and that Rb be 'There are sexual differences in both morphological and electrophysiological parameters in Necturus urinary bladder (Lefevre et al ., 1977 ;Higgins et al ., 1977) . From the stair-step potential profile of their record (Fromter and Gebler, 1977, Fig.…”

Section: Correlation Between Na Transport and Basolateral Membrane Potentialmentioning

confidence: 98%

Sodium transport effects on the basolateral membrane in toad urinary bladder.

Davis¹,

Finn²

1982

The Journal of General Physiology

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In toad urinary bladder epithelium, inhibition of Na transport with amiloride causes a decrease in the apical (Vmc) and basolateral (V,") membrane potentials . In addition to increasing apical membrane resistance (R.), amiloride also causes an increase in basolateral membrane resistance (Rb), with a time course such that R ./Rb does not change for 1-2 min. At longer times after amiloride (3-4 min), Rfl/Rb rises from its control values to its amiloride steady state values through a secondary decrease in Rb . Analysis of an equivalent electrical circuit of the epithelium shows that the depolarization of V.8 is due to a decrease in basolateral electromotive force (Vb) . To see if the changes in V. and Rb are correlated with a decrease in Na transport, external current (I.) was used to clamp Vnme to zero, and the effects of amiloride on the portion of le that takes the transcellular pathway were determined . In these studies, V, . also depolarized, which suggests that the decrease in Vb was due to a decrease in the current output of a rheogenic Na pump . Thus, the basolateral membrane does not behave like an ohmic resistor . In contrast, when transport is inhibited during basolateral membrane voltage clamping, the apical membrane voltage changes are those predicted for a simple, passive (i.e ., ohmic) element.

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“…It should be noted that the former study included data from both males and females without specifying the time of year at which the experiments were conducted. Urinary bladders from female Necturus are strikingly different from those of males, both morphologically and electrophysiologically (LeFevre et al, 1977;Higgins et al, 1977). The grouping of data derived from these two electrophysiologically distinct populations may have resulted in a spurious inverse correlation.…”

Section: Effects Of Decreasing Serosal Clon the Cell Membrane Resistances And Electromotive Forcesmentioning

confidence: 99%

Characterization of the basolateral membrane conductance of Necturus urinary bladder.

Demarest¹,

Finn²

1987

The Journal of General Physiology

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Necturus urinary bladders stripped of serosal muscle and connective tissue were impaled through their basolateral membranes with microelectrodes in experiments that permitted rapid changes in the ion composition of the serosal solution . The transepithelial electrical properties exhibited a marked seasonal variation that could be attributed to variations in the conductance of the shunt pathway, apical membrane selectivity, and basolateral Na' transport .

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Sex differences in Necturus urinary bladders

Cited by 6 publications

References 16 publications

Seasonal variations in the fine structure of the Necturus maculosus urinary bladder epithelium: Low transporters and high transporters

Seasonal variations in the fine structure of the Necturus maculosus urinary bladder epithelium: Low transporters and high transporters

Sodium transport effects on the basolateral membrane in toad urinary bladder.

Characterization of the basolateral membrane conductance of Necturus urinary bladder.

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