Alteration of calcium conductances and outward current by cyclic adenosine monophosphate (cAMP) in neurons of Limax maximus

Philip Hockberger, John A. Connor*

*Corresponding author for this work

Research output: Contribution to journalArticle

20 Scopus citations

Abstract

1. Membrane responses to cyclic adenosine monophosphate (cAMP) injections have been studied by means of voltage clamp, Ca-indicator dye, and ion substitution techniques in identified neurons from the abdominal ganglion of Limax maximus. 2. The ventral abdominal giant cell (AGC) displayed a response consisting of a decrease in outward current usually accompanied by a smaller enhancement of voltage-gated Ca2+ influx. Both responses were eliminated by external Cd2+ or Mn2+ and required membrane voltages more positive than -40 mV for expression. The enhanced influx persisted in Ba2+-substituted saline, while the decrease in outward current was blocked. 3. A group of dorsal neurons (RD1-3, LD1) showed a mixed Na-Ca influx induced by cAMP that could be activated over a wide range of membrane potentials (< - 100 to > - 20 mV). This flux caused a measurable increase in internal Ca2+. The influx was insensitive to Cd2+ and Mn2+ but was reduced by prolonged exposure to Co2+. 4. The relative magnitude of the Na-Ca flux ratio showed considerable variation between specimens. In immature animals the Ca component was absent. 5. The results demonstrated that elevation of intracellular cAMP can cause cell-specific changes of membrane conductance within closely associated neurons.

Original languageEnglish (US)
Pages (from-to)319-338
Number of pages20
JournalCellular and molecular neurobiology
Volume4
Issue number4
DOIs
StatePublished - Dec 1 1984

Keywords

  • arsenazo III
  • calcium
  • cyclic adenosine monophosphate (cAMP)
  • gastropod neurons
  • membrane conductance
  • voltage clamp

ASJC Scopus subject areas

  • Cellular and Molecular Neuroscience
  • Cell Biology

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