Faculty Collaboration Database

ATP-mediated Ca2+ signaling in preglomerular smooth muscle cells. Am J Physiol 1999 Mar;276(3):F450-6

Date

03/10/1999

Pubmed ID

10070169

DOI

10.1152/ajprenal.1999.276.3.F450

Scopus ID

2-s2.0-0032898639 (requires institutional sign-in at Scopus site)   26 Citations

Abstract

We performed studies to determine the effect of extracellular ATP on the intracellular Ca2+ concentration ([Ca2+]i) in freshly isolated microvascular smooth muscle cells (MVSMC). Suspensions of preglomerular MVSMC were prepared by enzymatic digestion and loaded with fura 2. Single cells were studied using a microscope-based fluorescence spectrophotometer during superfusion of a physiological salt solution with 1.8 mM Ca2+ and during exposure to similar solutions containing ATP. Under control conditions, baseline [Ca2+]i averaged 107 +/- 6 nM (n = 86 cells from 34 animals). ATP administration elicited concentration-dependent increases in [Ca2+]i. Exposure to ATP concentrations of 1, 10, and 100 microM increased intracellular Ca2+ to peak concentrations of 133 +/- 20, 338 +/- 37, and 367 +/- 35 nM, respectively (P < 0.05 vs. respective baseline). Steady-state [Ca2+]i increased to 113 +/- 15, 150 +/- 16 (P < 0.05 vs. baseline), and 180 +/- 12 nM (P < 0.05 vs. baseline) for the same groups. The [Ca2+]i response to ATP was also assessed in the absence of extracellular Ca2+ and during blockade of L-type Ca2+ channels with diltiazem. In these studies, exposure to 100 microM ATP induced a transient peak increase in [Ca2+]i with the plateau phase being totally abolished under Ca2+-free conditions and markedly attenuated during Ca2+ channel blockade, respectively. These data indicate that ATP-mediated P2-receptor activation increases [Ca2+]i in freshly isolated preglomerular MVSMC by stimulating Ca2+ release from intracellular stores, in addition to stimulating the influx of extracellular Ca2+ through voltage-gated L-type Ca2+ channels.

Author List

Inscho EW, Schroeder AC, Deichmann PC, Imig JD

MESH terms used to index this publication - Major topics in bold

Adenosine Triphosphate
Animals
Arteries
Arterioles
Calcium
Calcium Channel Blockers
Calcium Channels
Calcium Channels, L-Type
Calcium Signaling
Diltiazem
Dose-Response Relationship, Drug
Homeostasis
In Vitro Techniques
Intracellular Membranes
Kidney Glomerulus
Male
Muscle, Smooth, Vascular
Osmolar Concentration
Rats
Rats, Sprague-Dawley