|
|
||||||||
AJP - Regulatory, Integrative and Comparative Physiology, Vol 263, Issue 5 1086-R1092, Copyright © 1992 by American Physiological Society
ARTICLES |
D. A. Terreros and H. Kanli
Veterans Affairs Medical Center, Salt Lake City, Utah.
Osmoregulatory Ca2+ signaling in hypotonic solutions was studied with videometric techniques in 158 proximal renal tubules isolated from the teleost Carassius auratus. Absence of extracellular Ca2+, hypoxia (23 mmHg), or NaCN (3 mM) did not alter regulatory volume decreases (RVD). Nevertheless, decrements of intracellular Ca2+ via the A23187 ionophore or after intracellular Ca2+ chelation with indo-1/AM (5 microM) inhibited RVD. In tubules depleted of Ca2+, RVD could only be fully elicited when intracellular Ca2+ pulses were given within 1 min after hypotonic stimulation. While inhibition of Ca2+ release from the endoplasmic reticulum (ER) with 8-(diethylamino)octyl 3,4,5-trimethoxybenzoate hydrochloride (TMB-8, 50 microM) blunted RVD, some of its effects could be reversed with the anion carrier tributyltin (1 microM). Dibutyryl adenosine 3',5'-cyclic monophosphate (cAMP, 0.5 and 1.0 mM) and forskolin (0.25 mM) also impeded RVD; however, their effects could be partially reversed with the K+ ionophore gramicidin (0.5 microM). In conclusion, in Carassius auratus proximal renal tubule cells, RVD is activated by an intracellular Ca2+ signal that likely emanates from the ER and not from the extracellular media or the mitochondrial Ca2+ pool. Ca2+ activation of a cAMP-modulated osmoregulatory K+ channel appears to play an important role.
This article has been cited by other articles:
![]() |
L. Galizia, M. P. Flamenco, V. Rivarola, C. Capurro, and P. Ford Role of AQP2 in activation of calcium entry by hypotonicity: implications in cell volume regulation Am J Physiol Renal Physiol, March 1, 2008; 294(3): F582 - F590. [Abstract] [Full Text] [PDF] |
||||
![]() |
D. M. Cohen SRC family kinases in cell volume regulation Am J Physiol Cell Physiol, March 1, 2005; 288(3): C483 - C493. [Abstract] [Full Text] [PDF] |
||||
![]() |
D. B. Light, A. J. Attwood, C. Siegel, and N. L. Baumann Cell swelling increases intracellular calcium in Necturus erythrocytes J. Cell Sci., January 1, 2003; 116(1): 101 - 109. [Abstract] [Full Text] [PDF] |
||||
![]() |
C. Duranton, E. Mikulovic, M. Tauc, M. Avella, and P. Poujeol Potassium channels in primary cultures of seawater fish gill cells. II. Channel activation by hypotonic shock Am J Physiol Regulatory Integrative Comp Physiol, November 1, 2000; 279(5): R1659 - R1670. [Abstract] [Full Text] [PDF] |
||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| Visit Other APS Journals Online |