Application of small cardioactive peptide (SCP) or stimulation of moto
rneuron B15 increases the level of activated cAMP-dependent protein ki
nase (cAPK) in the ARC muscle. SCP application also appears to induce
a translocation of cAPK between different subcellular compartments of
the ARC muscle and this translocation is also induced by cAMP addition
to muscle homogenates. These results suggest that the actions of SCP
in the Aplysia ARC neuromuscular system are mediated via the cAPK sign
al transduction pathway.