How the Brain Becomes the Mind: Can Thermodynamics Explain the Emergence and Nature of Emotions?

The neural systems' electric activities are fundamental for the phenomenology of consciousness. Sensory perception triggers an information/energy exchange with the environment, but the brain's recurrent activations maintain a resting state with constant parameters. Therefore, perception forms a closed thermodynamic cycle.

The thermodynamic brain and the evolution of intellect: the role of mental energy.

The living state is low entropy, highly complex organization, yet it is part of the energy cycle of the environment. Due to the recurring presence of the resting state, stimulus and its response form a thermodynamic cycle of perception that can be modeled by the Carnot engine. The endothermic reversed Carnot engine relies on energy from the environment to increase entropy (i.

Relationships between short and fast brain timescales.

Brain electric activity exhibits two important features: oscillations with different timescales, characterized by diverse functional and psychological outcomes, and a temporal power law distribution. In order to further investigate the relationships between low- and high- frequency spikes in the brain, we used a variant of the Borsuk-Ulam theorem which states that, when we assess the nervous activity as embedded in a sphere equipped with a fractal dimension, we achieve two antipodal points with similar features (the slow and fast, scale-free oscillations). We demonstrate that slow and fast nervous oscillations mirror each other over time via a sinusoid relationship and provide, through the Bloch theorem from solid-state physics, the possible equation which links the two timescale activities.

Towards plasma-like collisionless trajectories in the brain.

Plasma studies depict collisionless, collective movements of charged particles. In touch with these concepts, originally developed by the far-flung branch of high energy physics, here we evaluate the role of collective behaviors and long-range functional couplingsof charged particlesin brain dynamics. We build a novel, empirically testable, brain model which takes into account collisionless movements of charged particles in a system, the brain, equipped with oscillations.

PEO-b-PCL grafted DPPC liposomes: physicochemical characterization and stability studies of novel bio-inspired advanced Drug Delivery nano Systems (aDDnSs).

Amphiphilic block copolymers and lipids have attracted major scientific interest in recent years due to their intriguing self-assembly behavior, which results in a plethora of nanoassemblies and their potential applications in Pharmaceutical Nanotechnology, as bio-inspired chimeric or hybrid advanced Drug Delivery nano Systems (aDDns). In this work, we report on stability studies of chimeric systems consisted of DPPC (dipalmitoylphosphatidylcholine) and poly(ethylene oxide)-block-poly(ε-caprolactone) (PEO-b-PCL) block copolymer in Phosphate Buffer Saline (PBS) and Fetal Bovine Serum (FBS). The incorporation of PEO-b-PCL leads to bio-inspired nanovectors of smaller size, in comparison to DPPC neat liposomes.

Protein kinase C-stimulated formation of ethanolamine from phosphatidylethanolamine involves a protein phosphorylation mechanism: negative regulation by p21 Ras protein.

Mammalian cells express a phospholipase D (PLD)-like enzyme which forms ethanolamine from phosphatidylethanolamine (PtdEtn) by a protein kinase C-alpha (PKC-alpha)-activated, presently unknown, mechanism. Now we report that addition of a PKC-alpha-enriched purified PKC preparation or recombinant PKC-alpha to a plasma membrane-enriched membrane fraction, isolated from leukemic HL60 cells, greatly ( approximately 6.5-fold stimulation) enhanced PtdEtn hydrolysis if the PKC activator phorbol 12-myristate 13-acetate (PMA) and ATP were both present; this was accompanied by PKC-mediated phosphorylation of several membrane proteins.

Preferential inhibition of phorbol ester-induced hydrolysis of phosphatidylethanolamine by N-acetylsphingosine in NIH 3T3 fibroblasts.

It has been reported that in rat fibroblasts cell-permeable ceramide analogs inhibit agonist-induced phospholipase D (PLD)-mediated hydrolysis of phosphatidylcholine (PtdCho). Here we demonstrate that relatively short (30 min) treatments of NIH 3T3 fibroblasts with 15-60 microM concentrations of N-acetylsphingosine result in preferential, although not exclusive, inhibition of phorbol 12-myristate 13-acetate-induced PLD-mediated hydrolysis of phosphatidylethanolamine (PtdEtn). The results suggest that in different cell types the PtdEtn- and PtdCho-hydrolyzing PLD activities are differentially sensitive to the inhibitory effect of ceramide.

Generation and remodeling of phospholipid molecular species in rat hepatocytes.

In order to assess the relationship between de novo phospholipid synthesis and remodeling by deacylation-reacylation, we have pulse-labeled glycerolipids by incubating rat hepatocytes in media containing either [U-14C]glycerol or H218O. Further incubation for up to 2 h in the absence of the labeled substrates and analysis of phosphatidylcholine (PC) and phosphatidylethanolamine (PE) provided information on the remodeling of newly synthesized molecular species by deacylation-reacylation at the sn-1 or sn-2 positions of glycerol. We conclude that de novo synthesis of PC and PE yields primarily four molecular species: 16:0-18:2 (n-6), 16:0-18:1, 16:0-22:6 (n-3), and 18:1-18:2 (n-6).

Regulation of phospholipase D by sphingosine involves both protein kinase C-dependent and -independent mechanisms in NIH 3T3 fibroblasts.

Previously, the protein kinase C (PKC) inhibitor sphingosine was found to stimulate phospholipase D (PLD)-mediated hydrolysis of both phosphatidylethanolamine (PtdEtn) and phosphatidylcholine (PtdCho) in NIH 3T3 fibroblasts [Kiss & Anderson (1990) J. Biol. Chem.

Effect of parathion and methylparathion on protein content of chicken embryo muscle in vivo.

Chicken eggs were treated with 0.4 per cent solutions of parathion or methylparathion for four or eight days, and the two-dimensional gel electrophoretic protein pattern of cervical muscles of eighteen days old embryos was analyzed. Both compounds significantly decreased the content of alpha-actinin, alpha-tubulin and beta-tubulin after four days treatment, and, in addition, that of three other related proteins (gamma-proteins) after eight days treatment.

Phorbol ester stimulation of sphingomyelin synthesis in human leukemic HL60 cells.

Pulse-chase experiments, performed with 14C-labeled choline, were used to study the possible effect of 12-O-tetradecanoylphorbol-13-acetate (TPA) on the terminal step of sphingomyelin (CerPCho) synthesis from phosphatidylcholine in intact human promyelocytic leukemic HL60 cells. Addition of TPA for the chase period significantly increased the rate of CerPCho synthesis; maximal stimulation (104%) required only 3 nM TPA. Treatment of cells with TPA for 6 h also increased the mass of CerPCho by 35%.

Cooperative interactions of protein kinase C and cAMP-dependent protein kinase systems in human promyelocytic leukemia HL60 cells.

Interactions of protein kinase C (PKC) and cAMP-dependent protein kinase (PKA) systems were investigated in HL60 cells. It was found that the differentiating effects of 12-O-tetradecanoylphorbol-13-acetate (TPA) were potentiated by dibutyryl cAMP (dbcAMP) or prostaglandin E2 (PGE2). In addition, dbcAMP or PGE2 inhibited TPA-induced binding of PKC to plasma membrane, leading to decreased protein phosphorylation, and promoted subsequent redistribution of enzyme to the nuclear membrane region.

Temporal changes in intracellular distribution of protein kinase C during differentiation of human leukemia HL60 cells induced by phorbol ester.

Immunocytochemical methods were used to study protein kinase C (PKC) distribution in HL60 cells during the entire course of 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced differentiation. After an initial translocation of PKC from cytoplasm to plasma membrane, the enzyme was localized close to the nuclear membrane region at day 1 of TPA treatment. PKC was associated with nuclei at day 2 and with nuclei, cytoplasma and plasma membrane at days 3 and 5.

Phorbol ester inhibits phosphatidylserine synthesis in human promyelocytic leukaemia HL60 cells. Possible involvement of free radicals and correlation with phosphorylation of nuclear protein 1b.

Treatment of human promyelocytic leukaemia HL60 cells in conditioned medium with 12-O-tetradecanoylphorbol 13-acetate (TPA) for 4 h resulted in 25-30% inhibition of labelling of phosphatidylserine (PS) with [U-14C]serine. PS labelling was 40% lower, and no inhibitory TPA effect was observed when the experiments were performed in fresh medium. Cycloheximide or puromycin also inhibited PS labelling by 38-44%; their inhibitory effects were non-additive with that of TPA and occurred only in conditioned medium.

Immunocytochemical localization of protein kinase C in resting and activated human neutrophils.

An immunocytochemical method was used to determine possible changes in the subcellular distribution of protein kinase C (PKC) in human neutrophils in response to opsonized latex beads and zymosan. While in resting cells most of the PKC immunoreactivity was localized in the cytoplasm, a redistribution of PKC to the plasma and phagosomal membranes was observed in cells treated with latex beads or zymosan for 5-20 min, suggesting a participation of PKC in endocytosis.

Comparative effects of polymyxin B, phorbol ester and bryostatin on protein phosphorylation, protein kinase C translocation, phospholipid metabolism and differentiation of HL60 cells.

The effects of protein kinase C (PKC) inhibitor polymyxin B (PMB) and PKC activators 12-O-tetradecanoylphorbol-13-acetate (TPA) and bryostatin on intact HL60 cells were examined. It was found that each of the three agents exhibited similar effects on phosphorylation of certain endogenous proteins, PKC translocation from cytoplasm to plasma membrane and formation of CDP-choline. TPA, however, was the only agent that stimulated phosphatidylcholine formation.

Cyclic AMP-like effects of polyamines on phosphatidylcholine synthesis and protein phosphorylation in human promyelocytic leukemia HL60 cells. Comparison with the effects of phorbol ester.

Spermine or putrescine increased cAMP levels through a catalase-sensitive mechanism, resulting in, most notably, a dephosphorylation of protein A (Mr 45,000, pI 5.15) and protein B (Mr 45,000, pI 4.9) and slightly increased phosphatidylcholine (PC) synthesis in HL60 cells.

Differential effects of various protein kinase C activators on protein phosphorylation in human acute myeloblastic leukemia cell line KG-1 and its phorbol ester-resistant subline KG-1a.

Human myeloid leukemia KG-1 cells are induced to differentiate to macrophage-like cells by tumor-promoting phorbol esters, such as 12-O-tetradecanoylphorbol-13-acetate (TPA). Cells from the cloned subline, KG-1a, unlike the parental line, are resistant to the differentiating effect of TPA. In the present studies, we investigated in these cells protein phosphorylation stimulated by various protein kinase C activators, including 1-oleoyl-2-acetylglycerol in the presence of the diacylglycerol kinase inhibitor R59022, TPA, mezerein, and bryostatin.

Antileukemic agent alkyllysophospholipid regulates phosphorylation of distinct proteins in HL60 and K562 cells and differentiation of HL60 cells promoted by phorbol ester.

The tumor-promoting 12-0-tetradecanoylphorbol-13-acetate (TPA) stimulated phosphorylation of several proteins in block I (including protein Ia) and protein 3 in HL60 cells. The antileukemic agent alkyllysophospholipid (ALP) inhibited the TPA-stimulated phosphorylation of these proteins and the TPA-induced differentiation of the cells. In comparison, TPA only stimulated phosphorylation of protein 3 in K562 cells which, in contrast, were not induced to differentiate by TPA and lacked protein Ia and had a very high basal phosphorylation of protein B.