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Updated: Jun 18, 2026

Immunohistochemical and Calcium Imaging Methods in Wholemount Rat Retina
08:54

Immunohistochemical and Calcium Imaging Methods in Wholemount Rat Retina

Published on: October 13, 2014

Calcium-dependent increases in protein kinase-A activity in mouse retinal ganglion cells are mediated by multiple

Timothy A Dunn1, Daniel R Storm, Marla B Feller

  • 1Neurobiology Section, Division of Biological Sciences, University of California San Diego, La Jolla, California, USA.

Plos One
|November 20, 2009
PubMed

Insights

Calcium-dependent protein kinase A (PKA) activation in neurons persists even without key adenylate cyclases (ACs). This suggests a soluble AC may mediate these crucial signaling pathways in neuronal development.

Area of Science:

  • Neuroscience
  • Cell Signaling
  • Molecular Biology

Background:

  • Neuronal activity induces long-term changes via second messenger cascades, notably the cyclic-AMP/Protein kinase A (cAMP/PKA) pathway.
  • Calcium-dependent activation of cAMP/PKA is vital for neuronal development, including cell survival and neurite outgrowth.
  • Adenylate cyclases (ACs) are the primary mediators linking calcium influx to cAMP/PKA pathway activation.

Purpose of the Study:

  • To investigate the role of different calcium-dependent adenylate cyclase classes in activating the cAMP/PKA pathway in retinal ganglion cells (RGCs).
  • To determine the specific ACs responsible for calcium-dependent PKA activation in response to neuronal depolarization.

Main Methods:

  • Dual imaging of intracellular calcium concentration and PKA activity in retinal ganglion cells (RGCs).
  • Utilized barrelless mice lacking AC1 and double knockout mice lacking AC1 and AC8.
  • Assessed PKA activity during inhibition of all transmembrane adenylate cyclases.

Main Results:

  • Depolarization-induced calcium-dependent PKA transients persisted in mice lacking AC1 and in double knockout mice lacking AC1 and AC8.
  • Inhibition of all transmembrane ACs did not abolish depolarization-induced PKA transients in a subset of RGCs.
  • These findings challenge the exclusive role of known transmembrane ACs in this signaling pathway.

Conclusions:

  • The persistence of PKA transients suggests the involvement of a non-canonical AC in calcium-dependent signaling.
  • A soluble adenylate cyclase is likely involved in mediating calcium-dependent cAMP/PKA activation in neurons.
  • This discovery opens new avenues for understanding neuronal plasticity and developmental signaling.

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