Schwartz and his co-workers have found that Aply- 
sia contains at least two protein kinase C genes 
with four transcripts. 
Like the predominant -y form in vertebrate ner- 
vous tissue, one Aplysia form can make use of 
arachidonic acid at low concentrations in place of 
diacylglycerol. The forms can be separated bio- 
»^chemically (differential association to membrane 
fractions in the presence of 10 mM Mg^^), and by 
antibodies raised against peptides synthesized ac- 
cording to appropriate carboxyl-terminal amino 
acid sequences inferred from the cloning data. 
Membranes of Aplysia neurons contain a 
30,000 protein that stimulates the activity of phos- 
pholipase (PLA^) only when phosphorylated. 
This protein, which Dr. Schwartz and his col- 
leagues have characterized and purified to homoge- 
neity, using a two-step purification procedure 
[DEAE (dimethylaminoethyl) chromatography fol- 
lowed by size-exclusion HPLC (high-performance 
liquid chromatography)], is associated with Aplysia 
PUBLICATIONS 
neural membranes. The purified protein can be 
phosphorylated in vitro by purified protein kinase 
C. Since sensitizing stimuli to the intact animal and 
application of serotonin to isolated clusters of sen- 
sory neurons activate protein kinase C by trans- 
locating the enzyme to membrane and since the ki- 
nase can cause the phosphorylation of the 
PLA^-stimulating protein, it is attractive to think 
that the key biochemical event sustaining the facili- 
tation is the initiation of a cycle that results in a 
persistently active protein kinase C, with arachi- 
donic acid causing continued activation of the ki- 
nase at the presynaptic site in sensory neuron ter- 
minals to which it initially was translocated. 
Dr. Schwartz is also Professor of Physiology and 
Cellular Biophysics and of Neurology at the Colum- 
bia University College of Physicians and Surgeons 
and Member of the Center for Neurobiology and 
Behavior, located at the New York Psychiatric In- 
stitute. 
Books and Chapters of Books 
Gallager, S.M., Bidwell, J.P, and Kuzirian, A.M. 1989. Strontium is required in artificial seawater for embry- 
onic shell formation in two species of bivalve molluscs. In Origin, History, and Modern Aspects of 
Biomineralization in Plants and Animals (Crick, R.E., Ed.). New York: Plenum, pp 349-366. 
Schwartz, J. H., and Greenberg, S.M. 1989. Turtles all the way down: some molecular mechanisms underlying 
long-term sensitization in Aplysia. In Neural Models of Plasticity (Byrne, J.H., Ed.). New York: Academic, 
pp 46-57. 
Articles 
Beushausen, S.A., Bergold, P, Sturner, S., Elste, A., Roytenberg, Y, Schwartz, J. H., and Bayley H. 1988. Two 
catalytic subunits of cAMP-dependent protein kinase generated by alternative RNA splicing are expressed 
in Aplysia neurons. Neuron 1:853-864. 
Chin, G.J., Shapiro, E., and Schwartz, J. H. 1989. Aplysia synaptosomes. II. Release of transmitters. J Neurosci 
9:49-55" 
Chin, G.J., Shapiro, E., Vogel, S.S., and Schwartz, J.H. 1989. Aplysia synaptosomes. I. Preparation and bio- 
chemical and morphological characterization of subcellular membrane fractions. J Neurosci 9:38-48. 
Feinmark, S.J., Piomelli, D., Shapiro, E., and Schwartz, J.H. 1989. Biologically active metabolites of the 12- 
lipoxygenase pathway are formed by Aplysia nervous tissue. Ann NY Acad Sci 559:121-130. 
Goldstein, R.S., and Schwartz, J.H. 1989. Catecholamine neurons in Aplysia-. improved light-microscopic res- 
olution and ultrastructural study using paraformaldehyde and glutaraldehyde (FaGlu) cytochemistry. 
J Neurobiol 2Q:20i-2lS. 
Hanlon, R., Bidwell, J.P, and Tait, R. 1989. Strontium is required for statolith development and thus normal 
swimming behavior of hatching cephalopods. J Exp Biol 141:187-195. 
Piomelli, D. , Feinmark, S.J., Shapiro, E. , and Schwartz, J.H. 1988. Formation and biological activity of 12- 
ketoeicosatetraenoic acid in the nervous system oi Aplysia. J Biol Chem 263:16591-16596. 
Continued 
534 
