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The pedunculopontine tegmental nucleus (PPN) and laterodorsal tegmental nucleus (LDT) are functionally associated brainstem structures implicated in behavioral state control and sensorimotor integration. The PPN is also involved in gait and posture, while the LDT plays a role in reward. Both nuclei comprise characteristic cholinergic neurons intermingled with glutamatergic and GABAergic cells whose absolute numbers in the rat have been only partly established. Here we sought to determine the complete phenotypical profile of each nucleus to investigate potential differences between them. Counts were obtained using stereological methods after the simultaneous visualization of cholinergic and either glutamatergic or GABAergic cells. The two isoforms of glutamic acid decarboxylase (GAD), GAD65 and GAD67, were separately analyzed. Dual in situ hybridization revealed coexpression of GAD65 and GAD67 mRNAs in 90% of GADpositive cells in both nuclei; thus, the estimated mean numbers of (1) cholinergic, (2) glutamatergic, and (3) GABAergic cells in PPN and LDT, respectively, were (1) 3,360 and 3,650; (2) 5,910 and 5,190; and (3) 4,439 and 7,599. These data reveal significant differences between PPN and LDT in their relative phenotypical composition, which may underlie some of the functional differences observed between them. The estimation of glutamatergic cells was significantly higher in the caudal PPN, supporting the reported functional rostrocaudal segregation in this nucleus. Finally, a small subset of cholinergic neurons (8% in PPN and 5% in LDT) also expressed the glutamatergic marker Vglut2, providing anatomical evidence for a potential corelease of transmitters at specific target areas. [ABSTRACT FROM AUTHOR]

Background: Approximately 35–40% of patients with chronic urticaria have an IgG autoantibody to the IgE receptor which can activate basophils and mast cells so that they release histamine. In this study we assessed the cytokine profile present in chronic urticaria sera, and then measured cytokine and leukotriene release from basophils and mast cells upon incubation with chronic urticaria sera. Finally we assessed cytokine expression at the single-cell level and characterized the T cell subpopulations involved in their production. We chose IL-4 as representative of Th2 lymphocytes and IFN-γ for Th1 lymphocytes. Methods: We analyzed IL-4, IL-5 and IFN-γ in 60 chronic urticaria sera versus 51 controls. Sera were incubated with purified human basophils and cutaneous mast cells and the release of histamine, IL-4 and leukotrienes (C[sub 4] , D[sub 4] , E[sub 4] ) was quantitated. Immunoblotting was performed to identify IgG antibody to FcεRIα, α subunit. We measured intracellular cytokine production in peripheral blood mononuclear cells of 17 chronic urticaria patients compared to 50 healthy controls. Results: We found higher IL-4 levels (p = 0.028) in the sera of chronic urticaria patients (1.03 pg/ml) versus healthy donors (0.20 pg/ml) but no difference between urticaria sera and atopic control sera (0.52 pg/ml). We did not detect IFN-γ or IL-5 in any serum. However, sera that activated basophils so that they released histamine also produced leukotriene and IL-4, and leukotriene production by cutaneous mast cells and basophils was closely correlated. However, there was no correlation between immunoblotting and the functional ability to induce either histamine or IL-4. After stimulating with PMA-ionomycin we found significant differences in CD4+ lymphocyte production of IL-4 and IFN-γ with no differences in CD8+ lymphocyte production of either cytokine. Conclusion: Our data support the presence of basophil and mast cell activators in the sera of patients with chronic urticaria which can lead to the production of leukotrienes and IL-4 in addition to the histamine. IL-4 levels are similar to those seen in atopic subjects. We found that CD4+ T cells from patients with chronic urticaria are activated and tend to produce higher cytokine levels than CD4+ T cells from healthy controls. There were no differences when cytokine production by CD8+ lymphocytes was similarly assessed. These results are consistent with the histology found in biopsies of chronic urticaria lesions, where a CD4+-predominant infiltrate is found with cytokine production suggesting either a Th0 response or a mixture of Th1 and Th2 lymphocytes.Copyright © 2002 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

Monoacylglycerol lipase inhibition (MAGL) has emerged as an interesting therapeutic target for neurodegenerative disease treatment due to its ability to modulate the endocannabinoid system and to prevent the production of proinflammatory mediators. To obtain a beneficial response, it is necessary to understand how this inhibition affects the neuron–glia crosstalk and neuron viability. In this study, the effect of MAGL inhibition by KML29 was evaluated in two types of rat cortical primary cultures; mixed cultures, including neuron and glial cells, and neuron-enriched cultures. The risk of neuronal death was estimated by longitudinal survival analysis. The spontaneous neuronal risk of death in culture was higher in the absence of glial cells, a process that was enhanced by KML29 addition. In contrast, neuronal survival was not compromised by MAGL inhibition in the presence of glial cells. Blockade of cannabinoid type 2 (CB2) receptors expressed mainly by microglial cells did not affect the spontaneous neuronal death risk but decreased neuronal survival when KML29 was added. Modulation of cannabinoid type 1 (CB1) receptors did not affect neuronal survival. Our results show that neuron–glia interactions are essential for neuronal survival. CB2 receptors play a key role in these protective interactions when neurons are exposed to toxic conditions. [ABSTRACT FROM AUTHOR]

Acrolein is a potent fixative that provides both excellent preservation of ultrastructural morphology and retention of antigenicity, thus it is frequently used for immunocytochemical detection of antigens at the electron microscopic level. However, acrolein is not commonly used for fluorescence microscopy because of concerns about possible autofluorescence and destruction of the luminosity of fluorescent dyes. Here we describe a simple protocol that allows fine visualization of two fluorescent markers in 40-mum sections from acrolein-perfused rat brain. Autofluorescence was removed by pretreatment with 1% sodium borohydride for 30 min, and subsequent incubation in a 50% ethanol solution containing 0.3% hydrogen peroxide enhanced fluorescence labeling. Thus, fluorescence labeling can be used for high-quality detection of markers in tissue perfused with acrolein. Furthermore, adjacent acrolein-fixed sections from a single experiment can be processed to produce high-quality results for electron microscopy or fluorescence labeling.