Blockade of colchicine-induced inhibition of vasopressin-stimulated osmotic water flow: failure to influence microtubule formation

1985 ◽  
Vol 249 (4) ◽  
pp. F464-F469
Author(s):  
D. A. Baron ◽  
R. M. Burch ◽  
P. V. Halushka ◽  
S. S. Spicer
Keyword(s):  
Urinary Bladder ◽  
Water Flow ◽  
Volume Fraction ◽  
Cyclooxygenase Inhibitors ◽  
Maximal Response ◽  
Prostaglandin E ◽  
Toad Urinary Bladder ◽  
Meclofenamic Acid ◽  
Osmotic Water ◽  
Osmotic Water Flow

Colchicine inhibits vasopressin-induced osmotic water flow across isolated toad urinary bladder. Concomitantly, colchicine has been shown to reduce the relative cytoplasmic volume fraction of microtubules in the apical granular cells of this epithelium that have been shown previously to mediate the hydroosmotic effect of vasopressin. Therefore, an intact cytoskeleton has been postulated to be a requirement for a full response to vasopressin. Since it has been demonstrated recently that cyclooxygenase inhibitors (meclofenamic acid) abrogate the inhibition by colchicine of vasopressin-stimulated water flow, we tested by stereological criteria the hypothesis that colchicine in the presence of meclofenamic acid does not prevent the polymerization of tubulin. Our results show that the relative cytoplasmic volume fraction of microtubules was reduced 75% by colchicine in the presence or absence of meclofenamic acid. An alternative explanation of the inhibitory action of colchicine is its ability in the toad urinary bladder to enhance the endogenous synthesis of and sensitivity to prostaglandin E, a potent negative modulator of vasopressin-stimulated water flow. An intact microtubular component of the cytoskeleton does not appear to be required for a maximal response to a physiological dose of vasopressin.

scholarly journals THE EFFECT OF SMOOTH MUSCLE ON THE INTERCELLULAR SPACES IN TOAD URINARY BLADDER

1970 ◽  
Vol 46 (2) ◽  
pp. 235-244 ◽  
Author(s):  
Donald R. DiBona ◽  
Mortimer M. Civan
Keyword(s):  
Smooth Muscle ◽  
Urinary Bladder ◽  
Water Flow ◽  
Toad Urinary Bladder ◽  
Reliable Index ◽  
Intercellular Spaces ◽  
Phase Microscopy ◽  
Osmotic Water ◽  
Smooth Muscle Relaxant ◽  
Osmotic Water Flow

Phase microscopy of toad urinary bladder has demonstrated that vasopressin can cause an enlargement of the epithelial intercellular spaces under conditions of no net transfer of water or sodium. The suggestion that this phenomenon is linked to the hormone's action as a smooth muscle relaxant has been tested and verified with the use of other agents effecting smooth muscle: atropine and adenine compounds (relaxants), K+ and acetylcholine (contractants). Furthermore, it was possible to reduce the size and number of intercellular spaces, relative to a control, while increasing the rate of osmotic water flow. A method for quantifying these results has been developed and shows that they are, indeed, significant. It is concluded, therefore, that the configuration of intercellular spaces is not a reliable index of water flow across this epithelium and that such a morphologic-physiologic relationship is tenuous in any epithelium supported by a submucosa rich in smooth muscle.

Effect of colchicine on the osmotic water flow across the toad urinary bladder

1975 ◽  
Vol 413 (2) ◽  
pp. 277-282 ◽  
Author(s):  
Shigekazu Yuasa ◽  
Shigeharu Urakabe ◽  
Genjiro Kimura ◽  
Dairoku Shirai ◽  
Yoshihiro Takamitsu ◽  
...  
Keyword(s):  
Urinary Bladder ◽  
Water Flow ◽  
Toad Urinary Bladder ◽  
Osmotic Water ◽  
Osmotic Water Flow

Polyclonal antibodies in study of ADH-induced water channels in frog urinary bladder

1991 ◽  
Vol 261 (3) ◽  
pp. F437-F442
Author(s):  
G. Valenti ◽  
G. Calamita ◽  
M. Svelto
Keyword(s):  
Urinary Bladder ◽  
Water Flow ◽  
Apical Membrane ◽  
Polyclonal Antibodies ◽  
Immune Serum ◽  
Frog Urinary Bladder ◽  
Hormonal Stimulation ◽  
Osmotic Water ◽  
Triton X ◽  
Osmotic Water Flow

It is now generally accepted that changes in water permeability in anti-diuretic hormone (ADH)-responsive target epithelial cells result from the insertion in the plasma apical membrane of new components that contain channels for water. The specificity of these channels suggests that they are formed by intrinsic proteins having access to both facies and spanning the whole membrane. We have previously shown that Triton X-100 apical extracts from ADH-stimulated frog urinary bladder contain some proteins inserted under hormonal stimulation. In the present study we have developed polyclonal antibodies using Triton X-100 extract as an immunogen. After considering the inhibitory effect exerted by the whole immune serum on the osmotic water flow, we used different adsorption steps to select, from the immune serum, antibodies to apical membrane proteins inserted in response to the hormone. Immunoblot analysis of these selected antibodies shows that they recognize seven to eight proteins, of which 55-, 35-, 26-, and 17-kDa proteins are always present. Antibodies to these four proteins, affinity purified on nitrocellulose sheets, inhibited ADH-induced osmotic water flow. Altogether these results strongly suggest that proteins of 55, 35, 26, and 17 kDa (or at least one of them) are likely to be involved in the mechanism of water transport.

Epoxygenase metabolites of arachidonic acid inhibit vasopressin response in toad bladder

1987 ◽  
Vol 253 (3) ◽  
pp. F464-F470 ◽  
Author(s):  
D. Schlondorff ◽  
E. Petty ◽  
J. A. Oates ◽  
M. Jacoby ◽  
S. D. Levine
Keyword(s):  
Arachidonic Acid ◽  
Water Flow ◽  
Rank Order ◽  
Intracellular Camp ◽  
Toad Urinary Bladder ◽  
Renal Tubules ◽  
Camp Content ◽  
Vicinal Diol ◽  
Osmotic Water ◽  
Osmotic Water Flow

In addition to cyclooxygenase and lipoxygenase pathways, the kidney can also metabolize arachidonic acid by a NADPH-dependent cytochrome P-450 enzyme to epoxyeicosatrienoic acids (EETs); furthermore, 5,6-EET has been shown to alter electrolyte transport across isolated renal tubules. We examined the effects of three EETs (5,6-, 11, 12-, and 14,15-EET) on osmotic water flow across toad urinary bladder. All three EETs reversibly inhibited vasopressin-stimulated osmotic water flow with 5,6- and 11,12-EET being the most potent. The effects appeared to be independent of prostaglandins. EETs inhibited the water flow response to forskolin but not (with the exception of 11,12-EET) the response to adenosine 3',5'-cyclic monophosphate (cAMP) or 8-BrcAMP, consistent with an effect on cAMP generation. For 11,12-EET the question of an additional inhibition at a site beyond or independent of cAMP has to be considered. To determine whether these effects were due to the EETs or to products of their metabolism, we examined the effects of their vicinal diol hydrolysis products, the dihydroxyeicosatrienoic acids. Nonenzymatic conversion of labeled 5,6-EET to its vicinal diol occurred rapidly in the buffer, whereas 11,12-EET was hydrolyzed in a saturable manner only when incubated in the presence of bladder tissue. The dihydroxyeicosatrienoic acids formed inhibited water flow in a manner paralleling that of the EETs. Both 5,6-EET and 11,12-EET (10(-5) M) prevented the increase in intracellular cAMP content observed in control tissues after vasopressin stimulation. Finally, 11,12- and 14,15-dihydroxyeicosatrienoic acid inhibited vasopressin- and forskolin-stimulated adenylate cyclase in the same rank order as their inhibition of water flow.(ABSTRACT TRUNCATED AT 250 WORDS)

Possible roles for microtubules and microfilaments in ADH action on toad urinary bladder

1979 ◽  
Vol 236 (1) ◽  
pp. F14-F20 ◽  
Author(s):  
W. A. Kachadorian ◽  
S. J. Ellis ◽  
J. Muller
Keyword(s):  
Water Flow ◽  
Cytochalasin B ◽  
Toad Urinary Bladder ◽  
Intramembranous Particle ◽  
Luminal Membrane ◽  
Osmotic Water ◽  
Particle Aggregates ◽  
Aggregation Phenomenon ◽  
Osmotic Water Flow ◽  
Intramembranous Particle Aggregates

Intramembranous particle aggregates in the luminal membrane of toad bladder granular cells after vasopressin stimulation have been found to correlate closely and specifically with induced alterations of water permeability. Roles for microtubules and microfilaments in mediating the latter response have been proposed on the basis of studies involving colchicine and cytochalasin B, respectively. In the present investigation the effects of these agents on both initiating and sustaining vasopressin-induced osmotic water flow and the particle aggregation phenomenon were studied. The results indicate that during initiation the aggregation and water flow responses to vasopressin are each colchicine- and cytochalasin B-sensitive and that these sensitivities can be wholly additive. However, after full vasopressin stimulation is established, the same responses demonstrate sensitivity only to cytochalasin B, not to colchicine. The findings, therefore, suggest that microtubules and microfilaments may be independently necessary for the initiation of the aggregation and water flow responses to vasopressin, and that microfilaments, but not microtubules, are required for their maintenance.

THE SWELLING OF FROG BLADDER CELLS PRODUCED BY OXYTOCIN

1965 ◽  
Vol 33 (2) ◽  
pp. 171-177 ◽  
Author(s):  
J. V. NATOCHIN ◽  
K. JANÁČEK ◽  
R. RYBOVÁ
Keyword(s):  
Urinary Bladder ◽  
Water Flow ◽  
Osmotic Gradient ◽  
Frog Urinary Bladder ◽  
Intracellular Space ◽  
Osmotic Water ◽  
Inulin Space ◽  
Bladder Cells ◽  
Synthetic Oxytocin ◽  
Osmotic Water Flow

SUMMARY (1) Synthetic oxytocin (100 m-u./ml.) produces swelling of the isolated frog urinary bladder even in the absence of an osmotic gradient across the bladder. (2) Calculations show that the change in intracellular space does not necessarily differ significantly from that in the presence of an osmotic gradient since the inulin space is markedly affected by the osmotic water flow. (3) Part of the cellular potassium is exchanged for sodium during the swelling produced by oxytocin. (4) A possible mechanism and the significance of the swelling is discussed.

Vasopressin-stimulated water flow is decreased by thromboxane synthesis inhibition or antagonism

1980 ◽  
Vol 239 (2) ◽  
pp. F160-F166
Author(s):  
R. M. Burch ◽  
D. R. Knapp ◽  
P. V. Halushka
Keyword(s):  
Urinary Bladder ◽  
Water Flow ◽  
Time Course ◽  
Arachidonic Acid Metabolism ◽  
Prostaglandin E ◽  
Toad Urinary Bladder ◽  
Thromboxane Synthetase ◽  
Positive Modulator ◽  
Dose Dependent Fashion ◽  
Dose Dependent

The time course of vasopressin stimulation of water flow and immunoreactive thromboxane B2 (iTXB2) and prostaglandin E (iPGE) biosynthesis was studied in the isolated toad urinary bladder. Vasopressin (25 mU/ml) significantly stimulated iTXB2 synthesis within 8 min, synthesis reaching a maximum rate by 17 min. iPGE synthesis was significantly stimulated within 8 min, remaining unchanged for 24 min. Maximum vasopressin-stimulated water flow was reached between 16 and 24 min. 7-(1-Imidazolyl)-heptanoic acid (7IHA), a thromboxane synthetase inhibitor, inhibited both vasopressin-stimulated water flow and iTXB2 synthesis in a dose-dependent fashion, but did not affect iPGE synthesis. Vasopressin-stimulated water flow and iTXB2 synthesis were significantly correlated (r = 0.75, n = 24, P less than 0.001). 13-Azaprostanoic acid (13APA), a thromboxane antagonist, inhibited vasopressin-stimulated water flow in a dose-dependent fashion. Inhibition of arachidonic acid metabolism abolished the effects of 7IHA and 13APA on vasopressin-stimulated water flow. 7IHA and 13APA had no effect on cAMP-stimulated water flow. These results confirm that vasopressin stimulates TXA2 and PGE synthesis and support the hypothesis that TXA2 is a positive modulator of vasopressin-stimulated water flow in the toad urinary bladder.

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