Evidence for a Calcium-Sensing Receptor in the Vascular Smooth Muscle Cells of the Spiral Modiolar Artery

Evidence for a Calcium-Sensing Receptor in the Vascular Smooth Muscle Cells of the Spiral... The vascular diameter of the gerbilline spiral modiolar artery has been shown to depend on the presence of extracellular Ca2+ but it remained unknown whether the smooth muscle cells of this arteriole contain a Ca2+ sensing receptor (CaSR). The cytosolic Ca2+ concentration ([Ca2+] i ) was monitored as fluo 3 fluorescence and the vascular diameter was measured by video-microscopy in isolated in vitro superfused spiral modiolar arteries. RT-PCR was used to probe for the presence of CaSR transcripts. Increasing the extracellular Ca2+ concentration ([Ca2+] o ) from 1 to 10 mm caused a biphasic increase in [Ca2+] i that was paralleled by a vasoconstriction. The initial rate of this vasoconstriction, 2.01 ± 0.07 μm/sec (n= 131), was inhibited when cytosolic Ca2+ stores were presumably depleted with thapsigargin (IC 50= 3 × 10−9 m, n= 26) or ryanodine (IC 50= 4 × 10−8 m, n= 25) or when PLC was inhibited by 10−6 m U73122 (n= 8). The initial rate of this constriction was not affected by the L-type Ca2+ channel blocker 10−6 m nifedipine (n= 5), by 10−6 m U73343 (n= 6), which is the inactive analogue of U73122, by the T-type Ca2+ channel blocker 10−6 Gd3+ (n= 6) or the Na+/Ca2+ exchanger blocker 10−4 m Ni2+ (n= 5). The agonist rank potency order was Gd3+ > Ni2+ > Ca2+ >> neomycin = Mg2+. Analysis of RNA isolated from the SMA revealed a RT-PCR product of the appropriate size for the CaSR (448 bp). Sequence analysis of the amplified cDNA fragment revealed a 94–96% amino acid identity compared to other CaSRs. These results demonstrate that the spiral modiolar artery contains a CaSR, which is most likely located in the vascular smooth muscle cells. http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png The Journal of Membrane Biology Springer Journals

Evidence for a Calcium-Sensing Receptor in the Vascular Smooth Muscle Cells of the Spiral Modiolar Artery

Loading next page...
Copyright © Inc. by 2000 Springer-Verlag New York
Life Sciences; Biochemistry, general; Human Physiology
Publisher site
See Article on Publisher Site

There are no references for this article.

You’re reading a free preview. Subscribe to read the entire article.

DeepDyve is your
personal research library

It’s your single place to instantly
discover and read the research
that matters to you.

Enjoy affordable access to
over 12 million articles from more than
10,000 peer-reviewed journals.

All for just $49/month

Explore the DeepDyve Library

Unlimited reading

Read as many articles as you need. Full articles with original layout, charts and figures. Read online, from anywhere.

Stay up to date

Keep up with your field with Personalized Recommendations and Follow Journals to get automatic updates.

Organize your research

It’s easy to organize your research with our built-in tools.

Your journals are on DeepDyve

Read from thousands of the leading scholarly journals from SpringerNature, Elsevier, Wiley-Blackwell, Oxford University Press and more.

All the latest content is available, no embargo periods.

See the journals in your area

Monthly Plan

  • Read unlimited articles
  • Personalized recommendations
  • No expiration
  • Print 20 pages per month
  • 20% off on PDF purchases
  • Organize your research
  • Get updates on your journals and topic searches


Start Free Trial

14-day Free Trial

Best Deal — 39% off

Annual Plan

  • All the features of the Professional Plan, but for 39% off!
  • Billed annually
  • No expiration
  • For the normal price of 10 articles elsewhere, you get one full year of unlimited access to articles.



billed annually
Start Free Trial

14-day Free Trial