The Psychedelic State Induced By Ayahuasca Modulates The Activity And Connectivity Of The Default Mode Network.

The experiences induced by psychedelics share a wide variety of subjective features, related to the complex changes in perception and cognition induced by this class of drugs. A remarkable increase in introspection is at the core of these altered states of consciousness. Self-oriented mental activity has been consistently linked to the Default Mode Network (DMN), a set of brain regions more active during rest than during the execution of a goal-directed task. Here we used fMRI technique to inspect the DMN during the psychedelic state induced by Ayahuasca in ten experienced subjects. Ayahuasca is a potion traditionally used by Amazonian Amerindians composed by a mixture of compounds that increase monoaminergic transmission. In particular, we examined whether Ayahuasca changes the activity and connectivity of the DMN and the connection between the DMN and the task-positive network (TPN). Ayahuasca caused a significant decrease in activity through most parts of the DMN, including its most consistent hubs: the Posterior Cingulate Cortex (PCC)/Precuneus and the medial Prefrontal Cortex (mPFC). Functional connectivity within the PCC/Precuneus decreased after Ayahuasca intake. No significant change was observed in the DMN-TPN orthogonality. Altogether, our results support the notion that the altered state of consciousness induced by Ayahuasca, like those induced by psilocybin (another serotonergic psychedelic), meditation and sleep, is linked to the modulation of the activity and the connectivity of the DMN.

Sorghum Flour Fractions: Correlations Among Polysaccharides, Phenolic Compounds, Antioxidant Activity And Glycemic Index.

Nutrients composition, phenolic compounds, antioxidant activity and estimated glycemic index (EGI) were evaluated in sorghum bran (SB) and decorticated sorghum flour (DSF), obtained by a rice-polisher, as well as whole sorghum flour (WSF). Correlation between EGI and the studied parameters were determined. SB presented the highest protein, lipid, ash, β-glucan, total and insoluble dietary fiber contents; and the lowest non-resistant and total starch contents. The highest carbohydrate and resistant starch contents were in DSF and WSF, respectively. Phenolic compounds and antioxidant activities were concentrated in SB. The EGI values were: DSF 84.5±0.41; WSF 77.2±0.33; and SB 60.3±0.78. Phenolic compounds, specific flavonoids and antioxidant activities, as well as total, insoluble and soluble dietary fiber and β-glucans of sorghum flour samples were all negatively correlated to EGI. RS content was not correlated to EGI.

Theobromine Increases Nad⁺/sirt-1 Activity And Protects The Kidney Under Diabetic Conditions.

Reduction in sirtuin 1 (Sirt-1) is associated with extracellular matrix (ECM) accumulation in the diabetic kidney. Theobromine may reduce kidney ECM accumulation in diabetic rats. In the current study, we aimed to unravel, under diabetic conditions, the mechanism of kidney ECM accumulation induced by a reduction in Sirt-1 and the effect of theobromine in these events. In vitro, we used immortalized human mesangial cells (iHMCs) exposed to high glucose (HG; 30 mM), with or without small interfering RNA for NOX4 and Sirt-1. In vivo, spontaneously hypertensive rats (SHR) were rendered diabetic by means of streptozotocin and studied after 12 wk. The effects of treatment with theobromine were investigated under both conditions. HG leads to a decrease in Sirt-1 activity and NAD(+) levels in iHMCs. Sirt-1 activity could be reestablished by treatment with NAD(+), silencing NOX4, and poly (ADP-ribose) polymerase-1 (PARP-1) blockade, or with theobromine. HG also leads to a low AMP/ATP ratio, acetylation of SMAD3, and increased collagen IV, which is prevented by theobromine. Sirt-1 or AMPK blockade abolished these effects of theobromine. In diabetic SHR, theobromine prevented increases in albuminuria and kidney collagen IV, reduced AMPK, elevated NADPH oxidase activity and PARP-1, and reduced NAD(+) levels and Sirt-1 activity. These results suggest that in diabetes mellitus, Sirt-1 activity is reduced by PARP-1 activation and NAD(+) depletion due to low AMPK, which increases NOX4 expression, leading to ECM accumulation mediated by transforming growth factor (TGF)-β1 signaling. It is suggested that Sirt-1 activation by theobromine may have therapeutic potential for diabetic nephropathy.

Imatinib Restores Vasp Activity And Its Interaction With Zyxin In Bcr-abl Leukemic Cells.

Vasodilator-stimulated phosphoprotein (VASP) and Zyxin are interacting proteins involved in cellular adhesion and motility. PKA phosphorylates VASP at serine 157, regulating VASP cellular functions. VASP interacts with ABL and is a substrate of the BCR-ABL oncoprotein. The presence of BCR-ABL protein drives oncogenesis in patients with chronic myeloid leukemia (CML) due to a constitutive activation of tyrosine kinase activity. However, the function of VASP and Zyxin in BCR-ABL pathway and the role of VASP in CML cells remain unknown. In vitro experiments using K562 cells showed the involvement of VASP in BCR-ABL signaling. VASP and Zyxin inhibition decreased the expression of anti-apoptotic proteins, BCL2 and BCL-XL. Imatinib induced an increase in phosphorylation at Ser157 of VASP and decreased VASP and BCR-ABL interaction. VASP did not interact with Zyxin in K562 cells; however, after Imatinib treatment, this interaction was restored. Corroborating our data, we demonstrated the absence of phosphorylation at Ser157 in VASP in the bone marrow of CML patients, in contrast to healthy donors. Phosphorylation of VASP on Ser157 was restored in Imatinib responsive patients though not in the resistant patients. Therefore, we herein identified a possible role of VASP in CML pathogenesis, through the regulation of BCR-ABL effector proteins or the absence of phosphorylation at Ser157 in VASP.