Governance of arteriolar oscillation by ryanodine receptors

Tsuneo Takenaka, Yoichi Ohno, Koichi Hayashi, Takao Saruta, Hiromichi Suzuki

Research output: Contribution to journalArticle

21 Citations (Scopus)

Abstract

To investigate the role of ryanodine receptors in glomerular arterioles, experiments were performed using an isolated perfused hydronephrotic kidney model. In the first series of studies, BAYK-8644 (300 nM), a calcium agonist, constricted afferent (19.6 ± 0.6 to 17.6 ± 0.5 μm, n = 6, P < 0.01) but not efferent arterioles. Furthermore, BAYK-8644 elicited afferent arteriolar oscillatory movements. Subsequent administration of nifedipine (1 μM) inhibited both afferent arteriolar oscillation and constriction by BAYK-8644 (to 19.4 ± 0.5 μm). In the second group, although BAYK-8644 constricted afferent arterioles treated with 1 μM of thapsigargin (19.7 ± 0.6 to 16.8 ± 0.6 μm, n = 5, P < 0.05), it failed to induce rhythmic contraction. Removal of extracellular calcium with EGTA (2 mM) reversed BAYK-8644-induced afferent arteriolar constriction (to 20.0 ± 0.5 μm). In the third series of investigations, ryanodine (10 μM) but not 2-aminoethoxyphenyl borate (100 μM) abolished afferent arteriolar vasomotion by BAYK-8644. In the fourth series of experiments, in the presence of caffeine (1 mM), the stronger activation of voltage-dependent calcium channels by higher potassium media resulted in greater afferent arteriolar constriction and faster oscillation. Our results indicate that L-type calcium channels are rich in preglomerular but not postglomerular microvessels. Furthermore, the present findings suggest that either prolonged calcium influx through voltage-dependent calcium channels (BAYK-8644) or sensitized ryanodine receptors (caffeine) is required to trigger periodic calcium release through ryanodine receptors in afferent arterioles.

Original languageEnglish
Pages (from-to)R125-R131
JournalAmerican Journal of Physiology - Regulatory Integrative and Comparative Physiology
Volume285
Issue number1 54-1
Publication statusPublished - 2003 Jul 1

Keywords

  • BAYK-8644
  • Caffeine
  • Glomerular circulation
  • Tubuloglomerular feedback
  • Voltage-dependent calcium channel

ASJC Scopus subject areas

  • Physiology
  • Physiology (medical)

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  • Cite this

    Takenaka, T., Ohno, Y., Hayashi, K., Saruta, T., & Suzuki, H. (2003). Governance of arteriolar oscillation by ryanodine receptors. American Journal of Physiology - Regulatory Integrative and Comparative Physiology, 285(1 54-1), R125-R131.