Segmentally distinct effects of depolarization on intracellular [Ca2+] in renal arterioles

P. K. Carmines, B. C. Fowler, P. D. Bell

Research output: Contribution to journalArticlepeer-review

118 Scopus citations


Experiments were performed to determine the influence of depolarization on intracellular Ca2+ concentration ([Ca2+]i) in renal arterioles and the possible role of voltage-gated Ca2+ channels in these responses. Glomeruli with attached arterioles and thick ascending limb were dissected from rabbit kidney and loaded with fura 2. [Ca2+]i of nonperfused arterioles was monitored using a microscope-based dual-excitation wavelength spectrofluorometry system. Afferent arteriolar [Ca2+]i averaged 150 ± 11 nM (n = 20) when bathed in Ringer solution containing 1.5 mM Ca2+ and 5 mM K+. Replacement of the normal Ringer solution with one containing 100 mM K+ significantly increased afferent arteriolar [Ca2+]i to 196 ± 12 nM. This response was abolished in the absence of extracellular Ca2+. In the presence of 1 μM nifedipine, 100 mM K+ elicited a 10% decrease in afferent arteriolar [Ca2+]i (P < 0.05). Thus nifedipine reversed the afferent [Ca2+]i response to depolarization, implicating voltage-gated Ca2+ channels as the influx pathway. In contrast to the behavior of afferent arterioles, the 100 mM K+ solution reduced efferent arteriolar [Ca2+]i from 188 ± 17 to 148 ± 13 nM (n = 11, P < 0.01), an effect that was not influenced by nifedipine. These observations support a role for voltage-gated Ca2+ channels in eliciting depolarization-induced increases in afferent arteriolar [Ca2+]i while failing to provide evidence for operation of such a mechanism at efferent arteriolar sites.

Original languageEnglish (US)
Pages (from-to)F677-F685
JournalAmerican Journal of Physiology - Renal Fluid and Electrolyte Physiology
Issue number5 34-5
StatePublished - Nov 1993


  • Nifedipine
  • Rabbit
  • Renal microvasculature
  • Voltage-gated calcium channels

ASJC Scopus subject areas

  • Physiology


Dive into the research topics of 'Segmentally distinct effects of depolarization on intracellular [Ca2+] in renal arterioles'. Together they form a unique fingerprint.

Cite this