Ca<SUP>2+</SUP> Buffering Function of Sarcoplasmic Reticulum in Rat Tail Arteries:Comparison in Normotensive and Spontaneously Hypertensive Rats

• Nomura Yukiko

  Department of Pharmacology,Nagoya City University Medical School,Mizuho-cho,Mizuho-ku,Nagoya 467-8601,Japan

• Asano Masahisa

  Department of Pharmacology,Nagoya City University Medical School,Mizuho-cho,Mizuho-ku,Nagoya 467-8601,Japan

Bibliographic Information

Other Title

• Ca〔2+〕 Buffering Function of Sarcoplasmic Reticulum in Rat Tail Arteries: Comparison in Normotensive and Spontaneously Hypertensive Rats
• Ca 2 Buffering Function of Sarcoplasmic Reticulum in Rat Tail Arteries Comparison in Normotensive and Spontaneously Hypertensive Rats

Abstract

The superficial buffer barrier function of the sarcoplasmic reticulum(SR)during rest and that during stimulation with Bay k 8644, an agonist of L−type Ca²⁺ channels, were compared in endotheliumdenuded strips of tail arteries from 13−week−old normotensive Wistar−Kyoto rats(WKY)and spontaneously hypertensive rats(SHR), by measuring the effects of cyclopiazonic acid(CPA)and thapsigargin that inhibit SR Ca²⁺−ATPase and the effect of ryanodine that depletes SR Ca²⁺.The addition of 10μM CPA induced a transient contraction that was not significantly different between WKY and SHR.The CPA−induced contraction was strongly inhibited by 100 nM nifedipine and was abolished by Ca²⁺−free solution in both strains.Thapsigargin(100 nM)or ryanodine(10 μM)induced similar, small transient contractions in the two strains.The addition of Bay k 8644(1−100 nM)almost failed to induce a contraction in both WKY and SHR.When the strips were preincubated with 10 μM CPA, 100 nM thapsigargin or 10 μM ryanodine, Bay k 8644 induced similar concentration−dependent contractions in the two strains.The amount of Ca²⁺ stored in the SR, as estimated from the 20 mM caffeine−induced contraction, was not significantly different between WKY and SHR.Our results suggest that the SR of rat tail arteries can buffer a large amount of Ca²⁺ that enters the cell during the rest and the Bay k 8644 stimulation, and these functions are not altered in SHR.

Journal

• The Japanese Journal of Pharmacology

  The Japanese Journal of Pharmacology 83 (4), 335-343, 2000

  The Japanese Pharmacological Society

Keywords

• Superficial buffer barrier function
• Sarcoplasmic reticulum Ca<SUP>2+</SUP>-ATPase
• Ca<SUP>2+</SUP> influx via L-type Ca<SUP>2+</SUP> channels
• Tail artery
• Spontaneously hypertensive rats(SHR)

Details

• CRID: 1390282679263681792
• NII Article ID: 10008184790
• NII Book ID: AA00691188
• DOI: 10.1254/jjp.83.335
• COI: 1:CAS:528:DC%2BD3cXmtV2ks74%3D
• ISSN: 13473506
• ISSN: 00215198
• NDL BIB ID: 5501279
• PubMed: 11001180
• Web Site: https://ndlsearch.ndl.go.jp/books/R000000004-I5501279
• Web Site: https://www.jstage.jst.go.jp/article/jjp/83/4/83_4_335/_pdf
• Web Site: https://search.jamas.or.jp/link/ui/2001031317
• Text Lang: en
• Data Source:
  • JaLC
  • NDL
  • Crossref
  • PubMed
  • CiNii Articles
• Abstract License Flag: Disallowed