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To study the role of protein kinase C (PKC) and its substrates in neuronal function, we have investigated the in vitro endogenous phosphorylation of the neuronal phosphoprotein F1 after induction of synaptic plasticity by long-term potentiation (LTP). The protein F1 phosphorylation was found to increase 5 min (Routtenberg et al., 1985), 1 hr (Lovinger et(More)
Unsaturated fatty acids (oleic acid and arachidonic acid) activate purified protein kinase C independently of phospholipid and Ca2+. Oleic acid activation of protein kinase C is as effective as phosphatidylserine and Ca2+. Ka values for oleic acid and arachidonic acid are 50 and 53 microM, respectively. In contrast to the cis fatty acids, a trans form(More)
cis-Fatty acids such as oleic acid or linoleic acid have been previously shown to induce full activation of protein kinase C in the absence of Ca2+ and phospholipids (Murakami, K., and Routtenberg, A. (1985) FEBS Lett. 192, 189-193; Murakami, K., Chan, S.Y., and Routtenberg, A. (1986) J. Biol. Chem. 261, 15424-15429). In this study, we have investigated the(More)
Previous correlative and interventive work from this laboratory has suggested that activation of protein kinase C (PKC) is important for the maintenance of the hippocampal long-term potentiation (LTP) response. One such study demonstrated that application of the cis-unsaturated fatty acid, oleate, a newly discovered PKC activator, could prolong the time(More)
ABCG2, also known as BCRP, is a high-capacity urate exporter, the dysfunction of which raises gout/hyperuricemia risk. Generally, hyperuricemia has been classified into urate 'overproduction type' and/or 'underexcretion type' based solely on renal urate excretion, without considering an extra-renal pathway. Here we show that decreased extra-renal urate(More)
Recent findings suggest that protein kinase C (PKC) regulates the persistence of long-term potentiation (LTP). To test the hypothesis that PKC inhibition would decrease persistence of potentiation we applied PKC inhibitors (mellitin, polymyxin B, H-7) by micropressure ejection to the intact hippocampus either before or after LTP induction. When inhibitor(More)
Protein kinase C has been shown to be a phospholipid/Ca2+-dependent enzyme activated by diacylglycerol (Nishizuka, Y. (1984) Nature 308, 693-697; Nishizuka, Y. (1984) Science 225, 1365-1370). We have reported that unsaturated fatty acids (oleic acid and arachidonic acid) can activate protein kinase C independently of Ca2+ and phospholipid (Murakami, K., and(More)
Certain forms of neuronal plasticity have been found to be expressed through alterations in brain protein phosphorylation, and its regulation by protein kinase activity. Of interest in this regard is the possibility that the decline in neuronal plasticity and cognitive function that occurs in advanced age may result in part from altered phosphorylation of(More)
Iontophoretic application of the phorbol ester 12-O-tetradecanoylphorbol-13-acetate (TPA) to the intact rat hippocampus enhances potentiation produced by subsequent high frequency stimulation of the perforant path. The decay of the enhanced population spike amplitude recorded in the hilar dentate gyrus was prevented in animals receiving ejections of TPA, as(More)
Activation of protein kinase C (PKC) facilitates long-term potentiation (LTP), a model of memory, and increases its substrate protein F1 (aka GAP43) phosphorylation in direct relation to synaptic enhancement. Unsaturated fatty acids (c-FAs) which activate purified PKC, when injected into hippocampus, enhance LTP. To determine if dietary c-FAs could alter(More)