Journal of Neuroscience, Vol 4, 1370-1377, Copyright © 1984 by Society for Neuroscience
Localization and characterization of gastrin/cholecystokinin-like immunoreactivity in the central nervous system of Aplysia californica
SR Vigna, JL Morgan and TM Thomas
Gastrin/cholecystokinin-like immunoreactivity (G/CCK-LI) was localized by
immunocytochemistry in neurons in the central nervous system of Aplysia
californica. Neuronal cell bodies were specifically immunostained in the
buccal, cerebral, pedal, and abdominal ganglia but not in the pleural
ganglia. Neural G/CCK-LI processes were observed in the neuropil of all
ganglia and connectives and in some but not all of the peripheral nerves
examined. Somata containing G/CCK-LI ranged from 15 to 200 micron in
diameter. Ganglionic G/CCK-LI was most efficiently extracted in neutral or
basic solutions and consisted mainly of a substance eluting in a volume
corresponding to a peptide of between 8 and 17 amino acid residues on gel
filtration. This G/CCK-LI diluted in parallel to mammalian gastrin in
radioimmunoassays using two antisera differing in their specificities for
the bioactive COOH-terminal region of mammalian G/CCK. We conclude that
G/CCK-LI is distributed widely in the central and peripheral nervous
systems of Aplysia californica and that this immunoreactivity probably
represents a small peptide which is similar but not identical to mammalian
gastrins and cholecystokinins at the functionally critical COOH terminus.