Search results for "Second messenger system"
showing 10 items of 54 documents
Reduced basal and stimulated (isoprenaline, Gpp(NH)p, forskolin) adenylate cyclase activity in Alzheimer's disease correlated with histopathological …
1991
Cyclic adenosine monophosphate (cAMP) is an adenylate cyclase borne second messenger involved in basic metabolic events. The beta-adrenoceptor sensitive adenylate cyclase was studied in post-mortem hippocampi of controls and Alzheimer patients. Virtually identical subsets of each hippocampus homogenate were stimulated by 100 mumol isoprenaline, Gpp(NH)p and forskolin, respectively, in presence of an ATP-regenerating system. The determination of cAMP formed was carried out by means of a radioassay. The observed significant 50% reduction in basal as well as in stimulated adenylate cyclase activity in Alzheimer's disease is negatively correlated with semiquantitative evaluations of amyloid pla…
Nitric oxide is formed in a subpopulation of rat pineal cells and acts as an intercellular messenger.
1998
In the rat pineal, formation of the second messenger cyclic GMP (cGMP) is under adrenergic control. Two important sequential steps mediate adrenergic signal transduction by cGMP, receptor-stimulated nitric oxide (NO) formation by the enzyme NO synthase I (NOS I), and NO-induced cGMP formation by the cytosolic enzyme guanylyl cyclase. With regard to the first step in cGMP transduction (i.e. NO formation) we found, by means of NOS I immunostaining and NADPH-diaphorase staining, that the presence of NOS I was restricted to a subpopulation of pineal cells, generally surrounded by NOS I-negative cells. Considering the fact that NO is able to permeate the cell membrane, the question arises whethe…
NO-Based Signaling in Plants
2006
In animals, nitric oxide (NO) is an endogenously produced radical involved in cell communication and signal transduction. Its functions in plants are currently being discovered at an unprecedented pace, and insight into NO-derived mechanisms has mainly been gained from research on signal transduction. Numerous studies have firmly placed NO as one component of the signal perception–transduction network that connects plant responses to primary signals, including hormones, elicitors of defence responses or abiotic stresses. Protein kinases and the second messengers Ca 2+, cGMP, and cADPR convey part of the NO signal within cells. Furthermore, NO-based protein modifications are emerging as broa…
International Union of Basic and Clinical Pharmacology. XCIV. Adhesion G Protein–Coupled Receptors
2015
The Adhesion family forms a large branch of the pharmacologically important superfamily of G protein-coupled receptors (GPCRs). As Adhesion GPCRs increasingly receive attention from a wide spectrum of biomedical fields, the Adhesion GPCR Consortium, together with the International Union of Basic and Clinical Pharmacology Committee on Receptor Nomenclature and Drug Classification, proposes a unified nomenclature for Adhesion GPCRs. The new names have ADGR as common dominator followed by a letter and a number to denote each subfamily and subtype, respectively. The new names, with old and alternative names within parentheses, are: ADGRA1 (GPR123), ADGRA2 (GPR124), ADGRA3 (GPR125), ADGRB1 (BAI1…
In murine 3T3 fibroblasts, different second messenger pathways resulting in the induction of NO synthase II (iNOS) converge in the activation of tran…
1996
Transcription factor NF-kappaB is essential for the induction of nitric oxide synthase (NOS) II (iNOS) by bacterial lipopolysaccharide in murine macrophages (Xie, Q. W., Kashiwabara, Y., and Nathan, C. (1994) J. Biol. Chem. 269, 4705-4708). In 3T3 fibroblasts, agents other than cytokines are efficacious inducers of NOS II expression. In addition to cytokines such as interferon-gamma or tumor necrosis factor-alpha, protein kinase C-stimulating agents such as tetradecanoylphorbol-13-acetate, or cyclic AMP-elevating agents such as forskolin and 8-bromo-cAMP markedly increased NOS II mRNA (measured by Sl nuclease and RNase protection analyses), NOS II protein (determined by Western blotting), a…
Signal transduction pathways of membrane expression of proteinase 3 (PR‐3) in human endothelial cells
1997
At present, the exact mechanism of the pathogenic effect of anti-PR-3 antibodies remains unknown. Interaction of anti-neutrophil cytoplasmic antibodies (ANCAs) with human umbilical vein endothelial cells (HUVECs) may play a key role. Recently we were able to show that ANCAs recognize their target antigen, PR-3, translocated into the membrane of HUVECs. The objective of this study was to investigate regulation, i.e. signal transduction pathways, of PR-3 expression in endothelial cells. HUVECs were isolated according to the method of Jaffe et al. and cultured under standard conditions. A cyto-enzyme-linked immunosorbent assay (ELISA) with unfixed cells was performed. Membrane-expressed PR-3 w…
Capsaicin differentially modulates voltage-activated calcium channel currents in dorsal root ganglion neurones of rats
2005
It is discussed whether capsaicin, an agonist of the pain mediating TRPV1 receptor, decreases or increases voltage-activated calcium channel (VACC) currents (ICa(V)). ICa(V) were isolated in cultured dorsal root ganglion (DRG) neurones of rats using the whole cell patch clamp method and Ba 2+ as charge carrier. In large diameter neurones (>35Am), a concentration of 50AM was needed to reduce ICa(V) (activated by depolarizations to 0 mV) by 80%, while in small diameter neurones (30Am), the IC50 was 0.36 AM. This effect was concentration dependent with a threshold below 0.025 AM and maximal blockade (>80%) at 5AM. The current–voltage relation was shifted to the hyperpolarized direction with an…
NO as a signalling molecule in the nervous system
2002
The discovery that nitric oxide (NO) functions as a signalling molecule in the nervous system has radically changed the concept of neural communication. Indeed, the adoption of the term nitrergic for nerves whose transmitter function depends on the release of NO or for transmission mechanisms brought about by NO (Moncada et al., 1997) emphasizes the specific characteristics of this mediator. The physical properties of NO prevent its storage in lipid-lined vesicles and metabolism by hydrolytic degradatory enzymes. Therefore, unlike established neurotransmitters, NO is synthesized on demand and is neither stored in synaptic vesicles nor released by exocytosis, but simply diffuses from nerve t…
Functional characterization of α1 -adrenoceptor subtypes in vascular tissues using different experimental approaches:a comparative study
2003
The α1-adrenergic responses of rat aorta and tail artery have been analysed measuring the contractility and the inositol phosphate (IP) formation induced by noradrenaline. Three antagonists, prazosin, 5-methylurapidil (α1A selective) and BMY 7378 (α1D selective) have been used in different experimental procedures. Noradrenaline possesses a greater potency inducing contraction and IP accumulation in aorta (pEC50-contraction=7.32±0.04; pEC50-IPs=6.03±0.08) than in the tail artery (pEC50-contraction=5.71±0.07; pEC50-IPs=5.51±0.10). Although the maximum contraction was similar in both tissues (Emax-tail=619.1±55.6 mg; Emax-aorta-698.2±40.8 mg), there were marked differences in the ability of th…
Rho-mediated activation of PI(4)P5K and lipid second messengers is necessary for promotion of angiogenesis by Semaphorin 4D
2011
Phosphatidylinositol 4-phosphate 5-kinase (PI(4)P5K) is a type I lipid kinase that generates the lipid second messenger phospholipid phosphatidylinositol 4,5-bisphosphate (PI(4,5)P2) and functions downstream of RhoA in actin organization. It is known to play an essential role in neurite remodeling, yielding a phenotype identical to that seen in cells treated with Semaphorin 4D (Sema4D), a protein that regulates proliferation, adhesion and migration in many different cell types. Plexin-B1, the receptor for Sema4D, activates RhoA in order to generate a pro-angiogenic signal in endothelial cells. Therefore, we looked in human umbilical vein endothelial cells (HUVEC) to determine if Plexin-B1 e…