Developmental changes in ryanodine- and IP(3)-sensitive Ca(2+) pools in ovine basilar artery

Am J Physiol Cell Physiol. 2001 Dec;281(6):C1785-96. doi: 10.1152/ajpcell.2001.281.6.C1785.

Abstract

To explore the hypothesis that cerebrovascular maturation alters ryanodine- and inositol 1,4,5-trisphosphate (IP(3))-sensitive Ca(2+) pool sizes, we measured total intracellular Ca(2+) with (45)Ca and the fractions of intracellular Ca(2+) released by IP(3) and/or caffeine in furaptra-loaded permeabilized basilar arteries from nonpregnant adult and term fetal (139-141 days) sheep. Ca(2+) mass (nmol/mg dry weight) was similar in adult (1.60 +/- 0.18) and fetal (1.71 +/- 0.16) arteries in the pool sensitive to IP(3) alone but was significantly lower for adult (0.11 +/- 0.01) than for fetal (1.22 +/- 0.11) arteries in the pool sensitive to ryanodine alone. The pool sensitive to both ryanodine and IP(3) was also smaller in adult (0.14 +/- 0.01) than in fetal (0.85 +/- 0.08) arteries. Because the Ca(2+) fraction in the ryanodine-IP(3) pool was small in both adult (5 +/- 1%) and fetal (7 +/- 4%) arteries, the IP(3) and ryanodine pools appear to be separate in these arteries. However, the pool sensitive to neither IP(3) nor ryanodine was 10-fold smaller in adult (0.87 +/- 0.10) than in fetal (8.78 +/- 0.81) arteries, where it accounted for 72% of total intracellular membrane-bound Ca(2+). Thus, during basilar artery maturation, intracellular Ca(2+) mass plummets in noncontractile pools, decreases modestly in ryanodine-sensitive pools, and remains constant in IP(3)-sensitive pools. In addition, age-related increases in IP(3) efficacy must involve factors other than IP(3) pool size alone.

Publication types

  • Comparative Study

MeSH terms

  • Animals
  • Basilar Artery / drug effects*
  • Basilar Artery / embryology*
  • Basilar Artery / growth & development
  • Basilar Artery / metabolism
  • Caffeine / pharmacology
  • Calcimycin / pharmacology
  • Calcium / metabolism*
  • Calcium Signaling / physiology*
  • Central Nervous System Stimulants / pharmacology
  • Dose-Response Relationship, Drug
  • Fetus
  • Guanosine Triphosphate / metabolism
  • Inositol 1,4,5-Trisphosphate / pharmacology*
  • Ionophores / pharmacology
  • Muscle Contraction / physiology
  • Ryanodine / pharmacology*
  • Sheep
  • Spectrometry, Fluorescence
  • Vanadates / pharmacology

Substances

  • Central Nervous System Stimulants
  • Ionophores
  • Ryanodine
  • Calcimycin
  • Caffeine
  • Vanadates
  • Inositol 1,4,5-Trisphosphate
  • Guanosine Triphosphate
  • Calcium