Coupling of vasopressin‐induced intracellular $Ca^{2+}$mobilization and apical exocytosis in perfused rat kidney collecting duct

Content Provider	Scilit
Author	Yip, Kay‐Pong
Copyright Year	2002
Description	Journal: The Journal of physiology Arginine vasopressin (AVP) regulates the osmotic water permeability of the kidney collecting duct by inducing exocytotic insertion of aquaporin‐2 into apical membrane. The coupling between AVP‐induced intracellular $Ca^{2+}$ mobilization and apical exocytosis was investigated in isolated perfused rat inner medullary collecting duct (IMCD) segments using confocal fluorescence microscopy. Changes of [Ca^{2+}$]_{i}$ in IMCD cells were measured with fluo‐4. A novel confocal imaging technique using a styryl dye, FM1‐43, was developed to monitor real‐time exocytosis induced by arginine vasopressin. AVP (0.1 nm) triggered a rapid increase of [Ca^{2+}$]_{i}$ in IMCD cells, followed by sustained oscillations. Ratiometric measurement of [Ca^{2+}$]_{i}$ confirmed that the observed [Ca^{2+}$]_{i}$ oscillation was a primary event and was not secondary to changes in cell volume. The frequencies of [Ca^{2+}$]_{i}$ oscillations in each IMCD cell were independent and time variant. 1‐Deamino‐8‐d‐arginine vasopressin (a $V_{2}$ receptor agonist, 0.1 nm) simulated the effects of AVP by triggering [Ca^{2+}$]_{i}$ oscillations. In the absence of extracellular $Ca^{2+}$, ryanodine (0.1 mm) inhibited AVP‐induced $Ca^{2+}$ mobilization. AVP (0.1 nm) triggered accumulative apical exocytosis in IMCD cells within 20 s after application. Pre‐incubating the IMCD with an intracellular $Ca^{2+}$ chelator, BAPTA, prevented AVP‐induced intracellular $Ca^{2+}$ mobilization, apical exocytosis, and increase of osmotic water permeability. These results indicate that AVP, via the $V_{2}$ receptor, triggers a calcium signalling cascade observed as [Ca^{2+}$]_{i}$ oscillations in the IMCD and that intracellular $Ca^{2+}$ mobilization is required for exocytotic insertion of aquaporin‐2.
Related Links	https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2290104/pdf
Ending Page	899
Page Count	9
Starting Page	891
ISSN	00223751
e-ISSN	14697793
DOI	10.1113/jphysiol.2001.012606
Journal	The Journal of physiology
Issue Number	3
Volume Number	538
Language	English
Publisher	Wiley-Blackwell
Publisher Date	2002-02-01
Access Restriction	Open
Subject Keyword	Journal: The Journal of physiology Osmotic Water Permeability
Content Type	Text
Resource Type	Article
Subject	Physiology Sports Science