Micromolar Ca2+ transients in dendritic spines of hippocampal pyramidal neurons in brain slice

Academic Article

Abstract

  • The magnitude and dynamics of [Ca2+] changes in spines and dendrites of hippocampal CA1 pyramidal neurons have been characterized using a low affinity fluorescent indicator, mag-Fura 5, that is sensitive to Ca2+ in the micromolar range. During tetanic stimulation (1 s), we observed progressive [Ca2+] increases in distal CA1 spines to as much as 20-40 μM, both in organotypic slice culture and acute slice. Similar accumulations were reached during continuous depolarization (+10 mV, 1 s) when K+ channels had been blocked, but not with spike trains driven by postsynaptic current injection. The large [Ca2+] increases due to tetanic stimulation were blocked by APV, indicating that NMDA receptor-dependent influx was critical for the large responses. These findings have significant implications for low affinity Ca2+-dependent biochemical processes and show a new upper limit for [Ca2+] changes measured in these neurons during stimulation. © 1995.
  • Published In

  • Neuron  Journal
  • Digital Object Identifier (doi)

    Author List

  • Petrozzino JJ; Pozzo Miller LD; Connor JA
  • Start Page

  • 1223
  • End Page

  • 1231
  • Volume

  • 14
  • Issue

  • 6