Tonically active protein kinase A regulates neurotransmitter release at the squid giant synapse.

Published

Journal Article

1. Electrophysiological and microinjection methods were used to examine the role of cyclic AMP-dependent protein kinase A (PKA) in regulating transmitter release at the squid giant synapse. 2. Excitatory postsynaptic potentials (EPSPs) evoked by presynaptic action potentials were not affected by presynaptic injection of an exogenous active catalytic subunit of mammalian PKA. 3. In contrast, presynaptic injection of PKI-amide, a peptide that inhibits PKA with high potency and specificity, led to a reversible inhibition of EPSPs. 4. Injection of several other peptides that serve as substrates for PKA also reversibly inhibited neurotransmitter release. The ability of these peptides to inhibit release was correlated with their ability to serve as PKA substrates, suggesting that these peptides act by competing with endogenous substrates for phosphorylation by active endogenous PKA. 5. We suggest that the phosphorylation of PKA substrates is maintained at a relatively high state under basal conditions and that this tonic activity of PKA is to a large degree required for evoked neurotransmitter release at the squid giant presynaptic terminal.

Full Text

Cited Authors

  • Hilfiker, S; Czernik, AJ; Greengard, P; Augustine, GJ

Published Date

  • February 2001

Published In

Volume / Issue

  • 531 / Pt 1

Start / End Page

  • 141 - 146

PubMed ID

  • 11179398

Pubmed Central ID

  • 11179398

Electronic International Standard Serial Number (EISSN)

  • 1469-7793

International Standard Serial Number (ISSN)

  • 0022-3751

Digital Object Identifier (DOI)

  • 10.1111/j.1469-7793.2001.0141j.x

Language

  • eng