Temperature-dependencies of various catalytic activities of membrane-bound Na+/K+-ATPase from ox brain, ox kidney and shark rectal gland and of C12E8-solubilized shark Na+/K+-ATPase

1988 ◽  
Vol 944 (3) ◽  
pp. 344-350 ◽  
Author(s):  
Mikael Esmann ◽  
Jens Christian Skou
Keyword(s):  
Rectal Gland ◽  
Catalytic Activities ◽  
Shark Rectal Gland ◽  
Membrane Bound

Cyclic AMP stimulates ouabain-insensitive ion movement in shark rectal gland

1984 ◽  
Vol 154 (2) ◽  
pp. 139-144 ◽  
Author(s):  
Patricio Silva ◽  
Kate Spokes ◽  
Jonathan A. Epstein ◽  
Arthur Stevens ◽  
Franklin H. Epstein
Keyword(s):  
Cyclic Amp ◽  
Rectal Gland ◽  
Ion Movement ◽  
Shark Rectal Gland

cAMP-activated C1 conductance is expressed in Xenopus oocytes by injection of shark rectal gland mRNA

1991 ◽  
Vol 260 (3) ◽  
pp. C664-C669 ◽  
Author(s):  
S. K. Sullivan ◽  
K. Swamy ◽  
M. Field
Keyword(s):  
Xenopus Oocytes ◽  
Functional Characterization ◽  
Equilibrium Potential ◽  
Rectal Gland ◽  
Calcium Buffer ◽  
Cl Channel ◽  
Shark Rectal Gland ◽  
Cl Channels ◽  
Cl Conductance

Development of reliable expression systems for use in identification and functional characterization of proteins required for secretory Cl channel activity is key to understanding the molecular basis of cystic fibrosis (CF). Until now, heterologous expression of epithelial Cl channels had not been accomplished. We show here that Xenopus oocytes express an adenosine 3',5'-cyclic monophosphate (cAMP)-activated Cl conductance after injection of mRNA from shark rectal gland. Current through this conductance was rapidly activated by intracellular application of cAMP, reversed near the chloride equilibrium potential (ECl), blocked by the Cl channel inhibitor 5-nitro-2-(3-phenylpropylamino) benzoate, and was not affected by preincubation with the intracellular calcium buffer bis-(2-amino-5-methylphenoxy)-ethane-N,N,N',N'-tetraacetic acid tetraacetoxymethyl ester, a condition that prohibits activation of the endogenous Ca-activated Cl conductance.

Cl- secretion by cultured shark rectal gland cells. II. Effects of forskolin on cellular electrophysiology

1991 ◽  
Vol 260 (4) ◽  
pp. C824-C831 ◽  
Author(s):  
W. M. Moran ◽  
J. D. Valentich
Keyword(s):  
Apical Membrane ◽  
Basolateral Membrane ◽  
Electrical Potential ◽  
Ringer Solution ◽  
Rectal Gland ◽  
Electrical Potential Difference ◽  
Electrophysiological Properties ◽  
Shark Rectal Gland ◽  
Membrane Electrical Potential ◽  
Cl Conductance

Employing microelectrode techniques we have assessed the cellular electrophysiological properties of shark rectal gland (SRG) cells in primary culture. In the absence of secretagogues a 10-fold reduction in the Cl- concentration of the apical superfusate shark Ringer solution had little effect on either apical membrane electrical potential difference (Va) or fractional resistance (fRa), indicating little, if any, apical membrane Cl- conductance. Superfusing the basolateral surface with high-K+ shark Ringer solution (K+ increased 10-fold) depolarized the basolateral membrane electrical potential difference (Vb) by 43 mV, indicating that this barrier is largely K+ conductive. In addition, basolateral Ba2+ (5 mM) depolarized Vb by 12 mV and reduced fRa from 0.92 to 0.58, results consistent with a K(+)-conductive basolateral membrane in unstimulated SRG cells. Basolateral forskolin (10(-6) M) depolarized Va by 25 mV and caused a dramatic reduction in fRa from 0.97 to approximately 0.10. Under these conditions, a 10-fold decrease in apical superfusate Cl- concentration depolarized Va by 37 mV, revealing an adenosine 3',5'-cyclic monophosphate-induced apical membrane Cl- conductance. The time course of the forskolin-induced changes in Va and Vb suggests that the basolateral membrane K+ conductance increased and maintained the driving force for apical Cl- exit, as in other Cl(-)-secreting epithelia. These electrophysiological properties compare favorably with those of the perfused SRG tubule and indicate that SRG primary cultures are a suitable model for Cl(-)-secreting epithelia.

Propionate induces cell swelling and K+ accumulation in shark rectal gland

1989 ◽  
Vol 257 (2) ◽  
pp. C377-C384 ◽  
Author(s):  
G. M. Feldman ◽  
F. N. Ziyadeh ◽  
J. W. Mills ◽  
G. W. Booz ◽  
A. Kleinzeller
Keyword(s):  
Atpase Activity ◽  
Propionic Acid ◽  
Exchange Process ◽  
Squalus Acanthias ◽  
Cell Swelling ◽  
Rectal Gland ◽  
Structural Elements ◽  
Acid Diffusion ◽  
Shark Rectal Gland ◽  
Solute Accumulation

Small organic anions have been reported to induce cell solute accumulation and swelling. To investigate the mechanism of swelling, we utilized preparations of rectal gland cells from Squalus acanthias incubated in medium containing propionate. Propionate causes cells to swell by diffusing across membranes in its nonionic form, acidifying cell contents, and activating the Na+-H+ antiporter. The Na+-H+ exchange process tends to correct intracellular pH (pHi), and thus it maintains a favorable gradient for propionic acid diffusion and allows propionate to accumulate. Activation of the Na+-H+ antiport also facilitates Na+ entry into the cell and Nai accumulation. At the same time Na+-K+-ATPase activity, unaffected by propionate, replaces Nai with Ki, whereas the K+ leak rate, decreased by propionate, allows Ki to accumulate. As judged by 86Rb+ efflux, the reduction in K+ leak was not due to propionate-induced cell acidification or reduction in Cli concentration. Despite inducing cell swelling, propionate did not disrupt cell structural elements and F actin distribution along cell membranes.

Taurine and cell volume maintenance in the shark rectal gland: cellular fluxes and kinetics

1988 ◽  
Vol 943 (1) ◽  
pp. 43-52 ◽  
Author(s):  
Fuad N. Ziyadeh ◽  
George M. Feldman ◽  
George W. Booz ◽  
Arnost Kleinzeller
Keyword(s):  
Cell Volume ◽  
Rectal Gland ◽  
Shark Rectal Gland

Cyclic AMP-dependent stimulation of Na,K-ATPase in shark rectal gland

1986 ◽  
Vol 94 (3) ◽  
pp. 205-215 ◽  
Author(s):  
D. Marver ◽  
S. Lear ◽  
L. T. Marver ◽  
P. Silva ◽  
F. H. Epstein
Keyword(s):  
Cyclic Amp ◽  
Rectal Gland ◽  
Shark Rectal Gland ◽  
Stimulation Of

scholarly journals Divergent CFTR orthologs respond differently to the channel inhibitors CFTRinh-172, glibenclamide, and GlyH-101

2012 ◽  
Vol 302 (1) ◽  
pp. C67-C76 ◽  
Author(s):  
Maximilian Stahl ◽  
Klaus Stahl ◽  
Marie B. Brubacher ◽  
John N. Forrest
Keyword(s):  
Short Circuit ◽  
Primary Cultures ◽  
Dimensional Structure ◽  
Rectal Gland ◽  
Xenopus Laevis Oocytes ◽  
Organ Perfusion ◽  
Perfusion Studies ◽  
Expression Studies ◽  
Maximum Inhibition ◽  
Shark Rectal Gland

Comparison of diverse orthologs is a powerful tool to study the structure and function of channel proteins. We investigated the response of human, killifish, pig, and shark cystic fibrosis transmembrane conductance regulator (CFTR) to specific inhibitors of the channel: CFTRinh-172, glibenclamide, and GlyH-101. In three systems, including organ perfusion of the shark rectal gland, primary cultures of shark rectal gland tubules, and expression studies of each ortholog in cRNA microinjected Xenopus laevis oocytes, we observed fundamental differences in the sensitivity to inhibition by these channel blockers. In organ perfusion studies, shark CFTR was insensitive to inhibition by CFTRinh-172. This insensitivity was also seen in short-circuit current experiments with cultured rectal gland tubular epithelial cells (maximum inhibition 4 ± 1.3%). In oocyte expression studies, shark CFTR was again insensitive to CFTRinh-172 (maximum inhibition 10.3 ± 2.5% at 25 μM), pig CFTR was insensitive to glibenclamide (maximum inhibition 18.4 ± 4.4% at 250 μM), and all orthologs were sensitive to GlyH-101. The amino acid residues considered responsible by previous site-directed mutagenesis for binding of the three inhibitors are conserved in the four CFTR isoforms studied. These experiments demonstrate a profound difference in the sensitivity of different orthologs of CFTR proteins to inhibition by CFTR blockers that cannot be explained by mutagenesis of single amino acids. We believe that the potency of the inhibitors CFTRinh-172, glibenclamide, and GlyH-101 on the CFTR chloride channel protein is likely dictated by the local environment and the three-dimensional structure of additional residues that form the vestibules, the chloride pore, and regulatory regions of the channel.

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