Capacitative calcium entry in smooth muscle cells from preglomerular vessels.

Content Provider	Semantic Scholar
Author	Fellner, Susan K. Arendshorst, William J.
Copyright Year	1999
Abstract	Calcium entry via voltage-gated L-type channels is responsible for at least half of the increase in cytosolic calcium ([Ca2+]i) in afferent arterioles following agonist stimulation. We sought the presence of capacitative calcium entry in fresh vascular smooth muscle cells (VSMC) derived from rat preglomerular vessels. [Ca2+]iwas measured using fura-2 ratiometric fluorescence. Vasopressin V1 receptor agonist (V1R) (10-7M) increased [Ca2+]iby ∼100 nM. A calcium channel blocker (CCB), nifedipine or verapamil (10-7 M), inhibited the response by ∼50%. V1R in the presence of CCB increased [Ca2+]ifrom 106 to 176 nM, confirming that calcium mobilization and/or entry may occur independent of voltage-gated channels. In nominally Ca2+-free buffer, V1R increased [Ca2+]ifrom 94 to 129 nM, denoting mobilization; addition of CaCl2 (1 mM) further elevated [Ca2+]ito 176 nM, indicating a secondary phase of Ca2+ entry. Similar responses were obtained when CCB was present in calcium-free buffer or when EGTA was present. In nominally Ca2+-free medium, the sarcoplasmic reticulum Ca2+-ATPase inhibitors (SRCAI), thapsigargin and cyclopiazonic acid (CPA), increased [Ca2+]ifrom 97 to 128 and 143 nM, respectively, and to 214 and 220 nM, respectively, when 1 mM extracellular Ca2+ was added. In the presence of verapamil, the results with CPA acid were nearly identical. In Ca2+-free buffer, the stimulatory effect of V1R or SRCAI on the Ca2+/fura signal was quenched by the addition of Mn2+ (1 mM), demonstrating divalent cation entry. These studies provide evidence for capacitative (store- operated) calcium entry in VSMC freshly isolated from rat preglomerular arterioles.
Starting Page	F533
Ending Page	F542
Page Count	1
File Format	PDF HTM / HTML
Alternate Webpage(s)	http://ajprenal.physiology.org/content/ajprenal/277/4/F533.full.pdf
PubMed reference number	29598150v1
Alternate Webpage(s)	https://doi.org/10.1152/ajprenal.1999.277.4.F533
DOI	10.1152/ajprenal.1999.277.4.f533
Journal	American journal of physiology. Renal physiology
Volume Number	277
Issue Number	4
Language	English
Access Restriction	Open
Subject Keyword	Adrenergic alpha-Agonists Argipressin Blood Vessel Buffers Calcium Channel Blockers Cations Cations, Divalent Egtazic Acid Fluorescence Fura-2 Manganese Cation (2+) Muscle Cells Muscle, Smooth, Vascular Myocytes, Smooth Muscle Nifedipine Smooth muscle (tissue) Structure of arteriole Thapsigargin Thioctic Acid Verapamil cyclopiazonic acid release of sequestered calcium ion into cytoplasm store-operated calcium entry
Content Type	Text
Resource Type	Article