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Pharmacologic activation of endogenous protein kinase C (PKC) together with elevation of the intracellular Ca2+ level was previously shown to cause reduction of two voltage-dependent K+ currents (IA and ICa2+-K+) across the soma membrane of the type B photoreceptor within the eye of the mollusc Hermissenda crassicornis. Similar effects were also found to(More)
A series of studies on Hermissenda classical conditioning has lead to a discovery that the biophysical events (accumulation of Ca2+ and depolarization in B cell) found during memory acquisition are clearly distinct from those (suppression of K-currents, IA and ICa2+K+) detected in the retention phase of memory. Biochemical analysis of eyes isolated shortly(More)
Thrombomodulin (TM) antigen and its cofactor activity for thrombin-dependent protein C activation were not detected in the untreated HL-60 human promyelocytic cell line, but appeared in cells cultured with 1 alpha,25-dihydroxyvitamin D3 (1 alpha,25(OH)2D3: 10-1,000 nM) or phorbol 12-myristate 13-acetate (PMA: 0.1-10 nM) accompanied by an increase in TM mRNA(More)
Type B photoreceptors of the nudibranch mollusc Hermissenda crassicornis receive excitatory synaptic potentials (EPSPs) whose frequency is controlled by potential changes of a neighboring cell known as the S optic ganglion cell which is thought to be electrically coupled to the presynaptic source of these EPSPs, the E optic ganglion cell. The frequency of(More)
Voltage-dependent K+ currents, IA and ICa2+-K+, across the soma membrane of the Hermissenda Type B photoreceptor, have been shown to remain reduced during retention of classically conditioned behavior. IA and ICa2+-K+ undergo prolonged reduction due to [Ca2+]i elevation produced by a single pairing of a light step with a command depolarization or by(More)
Phosphoproteins in the CNS of the nudibranch mollusc, Hermissenda crassicornis, were analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and autoradiography. After preincubation in artificial sea-water containing 32P, nervous systems were exposed to elevation of external K+ (100 or 300 mM) for a period (e.g., 30 min) approximating a period(More)
In mammalian systems, Ca2+/diacylglycerol-activated phospholipid-dependent protein kinase (C-kinase) appears to play an important role in regulating physiological responses that outlast the transient rise in cytosolic Ca2+. Electrophysiological experiments in neurons of the nudibranch mollusc, Hermissenda crassicornis, have suggested a role for C-kinase in(More)
Ghrelin, an acylated peptide produced predominantly in the stomach, stimulates feeding and growth hormone (GH) secretion via interaction with the GH secretagogue receptor. Ghrelin molecules are present in two major endogenous forms, an acylated form (ghrelin) and a des-acylated form (des-acyl ghrelin). Recent studies indicated that aerobic exercise did not(More)
Tsukahara creatively exploited the advantages of a "simple system" approach in a vertebrate context to gain cellular insights into the learning process. The molluscs Aplysia and Hermissenda have provided useful invertebrate examples of this approach. For classical conditioning of Hermissenda a temporal sequence of cellular transformations has been found to(More)