Development of depolarization-induced calcium transients in insect glial cells is dependent on the presence of afferent axons

Christian Lohr, Eric Tucker, Lynne A Oland, Leslie P Tolbert

Research output: Contribution to journalArticle

13 Citations (Scopus)

Abstract

Changes in the intracellular Ca2+ concentration ([Ca2+]i) induced by depolarization have been measured in glial cells acutely isolated from antennal lobes of the moth Manduca sexta at different postembryonic developmental stages. Depolarization of the glial cell membrane was elicited by increasing the external K+ concentration from 4 to 25 mM. At midstage 5 and earlier stages, less than 20% of the cells responded to 25 mM K+ (1 min) with a transient increase in [Ca2+]i of approximately 40 nM. One day later, at late stage 5, 68% of the cells responded to 25 mM K+, the amplitude of the [Ca2+]i transients averaging 592 nM. At later stages, all cells responded to 25 mM K+ with [Ca2+]i, transients with amplitudes not significantly different from those at late stage 5. In stage 6 glial cells isolated from deafferented antennal lobes, i.e., from antennal lobes chronically deprived of olfactory receptor axons, only 30% of the cells responded with [Ca2+]i transients. The amplitudes of these [Ca2+]i transients averaged 93 nM and were significantly smaller than those in normal stage 6 glial cells. [Ca2+]i transients were greatly reduced in Ca2+-free, EGTA-buffered saline, and in the presence of the Ca2+ channel blockers cadmium and verapamil. The results suggest that depolarization of the cell membrane induces Ca2+ influx through voltage-activated Ca2+ channels into antennal lobe glial cells. The development of the depolarization-induced Ca2+ transients is rapid between midstage 5 and stage 6, and depends on the presence of afferent axons from the olfactory receptor cells in the antenna.

Original languageEnglish (US)
Pages (from-to)85-98
Number of pages14
JournalJournal of Neurobiology
Volume52
Issue number2
DOIs
StatePublished - 2002

Fingerprint

Neuroglia
Axons
Insects
Calcium
Odorant Receptors
Cell Membrane
Olfactory Receptor Neurons
Manduca
Moths
Egtazic Acid
Verapamil
Cadmium

Keywords

  • Antennal lobe
  • Calcium channel
  • Fura-2
  • Manduca sexta
  • Neuron-glia interaction

ASJC Scopus subject areas

  • Neuroscience(all)

Cite this

Development of depolarization-induced calcium transients in insect glial cells is dependent on the presence of afferent axons. / Lohr, Christian; Tucker, Eric; Oland, Lynne A; Tolbert, Leslie P.

In: Journal of Neurobiology, Vol. 52, No. 2, 2002, p. 85-98.

Research output: Contribution to journalArticle

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abstract = "Changes in the intracellular Ca2+ concentration ([Ca2+]i) induced by depolarization have been measured in glial cells acutely isolated from antennal lobes of the moth Manduca sexta at different postembryonic developmental stages. Depolarization of the glial cell membrane was elicited by increasing the external K+ concentration from 4 to 25 mM. At midstage 5 and earlier stages, less than 20{\%} of the cells responded to 25 mM K+ (1 min) with a transient increase in [Ca2+]i of approximately 40 nM. One day later, at late stage 5, 68{\%} of the cells responded to 25 mM K+, the amplitude of the [Ca2+]i transients averaging 592 nM. At later stages, all cells responded to 25 mM K+ with [Ca2+]i, transients with amplitudes not significantly different from those at late stage 5. In stage 6 glial cells isolated from deafferented antennal lobes, i.e., from antennal lobes chronically deprived of olfactory receptor axons, only 30{\%} of the cells responded with [Ca2+]i transients. The amplitudes of these [Ca2+]i transients averaged 93 nM and were significantly smaller than those in normal stage 6 glial cells. [Ca2+]i transients were greatly reduced in Ca2+-free, EGTA-buffered saline, and in the presence of the Ca2+ channel blockers cadmium and verapamil. The results suggest that depolarization of the cell membrane induces Ca2+ influx through voltage-activated Ca2+ channels into antennal lobe glial cells. The development of the depolarization-induced Ca2+ transients is rapid between midstage 5 and stage 6, and depends on the presence of afferent axons from the olfactory receptor cells in the antenna.",
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