pCMBS-induced swelling of dogfish (Squalus acanthias) rectal gland cells: role of the Na+,K(+)-ATPase and the cytoskeleton.
(1) 0.1-1.0 mM p-chloromercuribenzene sulfonate (pCMBS) and some other organic mercurials produce a swelling of slices of dogfish shark (Squalus acanthias) rectal glands, with an uptake of cell Na+ and a loss of K+. In contrast, 1 mM N-ethylmaleimide (NEM) does not swell rectal gland cells (RGC), while affecting cell cations. (2) The slow entry of [203Hg]pCMBS is linearly related to its external concentration (10 microM-1 mM) and a small accumulation of pCMBS (apparent gradient about 3) in the cells occurs in 2 h. Cell 203Hg rapidly washes out of the cells (fast rate constant 0.153.min-1; slow rate constant 0.0067.min-1), and this efflux is accelerated by 1mM dithiothreitol. Thus, a major portion of pCMBS inter-acts rather loosely with cell components. (3) pCMBS and NEM share: (a) a negligible effect on the efflux of 86Rb+ and of [14C]urea; (b) a gradual inhibition of the cell Na+,K(+)-ATPase activity. (4) NEM as well as agents lowering cell glutathione accelerate and increase the pCMBS-induced cell swelling. Conditions inhibiting the Na+,K(+)-ATPase (ouabain, absence of Na+) have the same effect. (5) pCMBS, but not NEM produce a disappearance of the F-actin-phalloidin fluorescence independent of cell volume changes, particularly at the basolateral RGC membrane. (6) The data are consistent with the following set of events: (a) pCMBS (but not NEM) affects the cell membrane by increasing the efflux of the cell osmolyte taurine (Ziyadeh et al. (1988) Biochim. Biophys. Acta 943, 43-52 and unpublished data); (b) on entry into the cells, pCMBS and NEM interact with cell -SH, including those of the Na+,K(+)-ATPase; this action produces the observed changes in cell cations. Also, pCMBS, but not NEM, decrease F-actin at the membrane; (c) the inhibition of the Na+,K(+)-ATPase activity together with the decreased resistance of the cell membrane to stretch (absence of F-actin) produces the observed pCMBS-induced cell swelling by osmotic forces (intracellular non-diffusible anions).
Kleinzeller
A
A
Department of Physiology, University of Pennsylvania, Philadelphia 19104-6085.
Booz
G W
GW
Mills
J W
JW
Ziyadeh
F N
FN
D002731:4-Chloromercuribenzenesulfonate / Q000494:pharmacology*; D000199:Actins / Q000378:metabolism; D000818:Animals; D001693:Biological Transport, Active; D003599:Cytoskeleton / Q000187:drug effects / Q000201:enzymology*; D004284:Dogfish; D004910:Erythrocyte Membrane / Q000187:drug effects; D005033:Ethylmaleimide / Q000494:pharmacology; D066298:In Vitro Techniques; D010663:Phenylmercury Compounds / Q000494:pharmacology*; D011188:Potassium / Q000378:metabolism; D012491:Salt Gland / Q000187:drug effects* / Q000473:pathology; D012964:Sodium / Q000378:metabolism; D015222:Sodium Channels / Q000187:drug effects; D000254:Sodium-Potassium-Exchanging ATPase / Q000502:physiology*; D013438:Sulfhydryl Compounds / Q000494:pharmacology*
D000199:Actins; D010663:Phenylmercury Compounds; D015222:Sodium Channels; D013438:Sulfhydryl Compounds; D002731:4-Chloromercuribenzenesulfonate; D012964:Sodium; D000254:Sodium-Potassium-Exchanging ATPase; D005033:Ethylmaleimide; D011188:Potassium