Search results for "Forskolin"

Forskolin:valutazione efficacia ipotensiva nei pazienti in terapia massimale

2008

Modulation of NMDA receptor function by cyclic AMP in cerebellar neurones in culture

2004

The signal transduction pathways involved in NMDA receptor modulation by other receptors remain unclear. cAMP could be involved in this modulation. The aim of this work was to analyse the contribution of cAMP to NMDA receptor modulation in cerebellar neurones in culture. Forskolin increases cAMP and results in increased intracellular calcium and cGMP that are prevented by blocking NMDA receptors. Similar effects were induced by two cAMP analogues, indicating that cAMP leads to NMDA receptor activation. It has been reported that phosphorylation of Ser897 of the NR1 subunit of NMDA receptors by cAMP-dependent protein kinase (PKA) activates the receptors. Forskolin increases Ser897 phosphoryla…

The nicardipine-isoprenaline interaction in human and guinea-pig isolated airways

1994

Summary— The effects of the dihydropyridine calcium antagonist nicardipine on the concentration-response curves of relaxant compounds acting through the adenylate-cyclase/cAMP system (isoprenaline, forskolin, adenosine and theophylline) or by the cGMP pathway (sodium nitroprusside) were studied on human isolated bronchus and guinea-pig isolated trachea. These effects were compared with those of nifedipine (a dihydropyridine derivative) and theophylline (a non-selective phosphodiesterase inhibitor). Nicardipine, in the range of 0.01 to 1 μM, significantly potentiated the relaxant effects of isoprenaline, forskolin, adenosine and theophylline, whereas the effects of sodium nitroprusside were …

Mechanisms underlying hyperpolarization evoked by P2Y receptor activation in mouse distal colon

2006

In murine colonic circular muscle, ATP mediates fast component of the nerve-evoked inhibitory junction potentials, via activation of P2Y receptors and opening of apamin-sensitive Ca2+-dependent K+ channels. We investigated, using microelectrode recordings, the intracellular events following P2Y-receptor activation by electrical field stimulation or by adenosine 5'-O-2-thiodiphosphate (ADPbetaS), ATP stable analogue. The fast-inhibitory junction potential amplitude was reduced by thapsigargin or ciclopiazonic acid (CPA), sarcoplasmic reticulum Ca2+-ATPase inhibitors, by ryanodine, which inhibits Ca2+ release from ryanodine-sensitive stores, and by 9-(tetrahydro-2-furanyl)-9H-purin-6-amine (S…

Adrenergic modulation of the release of 5-hydroxytryptamine from the vascularly perfused ileum of the guinea-pig

1988

1. Isolated segments of the guinea-pig ileum were vascularly perfused and the release of 5-hydroxytryptamine (5-HT) and 5-hydroxyindoleacetic acid (5-HIAA) into the portal venous effluent was determined by h.p.l.c. with electrochemical detection. Test substances were applied via the arterial perfusion medium. 2. Isoprenaline (0.1 microM) increased the outflow of 5-HT and 5-HIAA maximally by about 75% and this was antagonized by propranolol (0.1 microM). Forskolin (1-10 microM) increased the outflow of 5-HT by approximately 105% and that of 5-HIAA by approximately 55%. The phosphodiesterase inhibitor AH 21-132 (0.1-1 microM) increased the outflow of 5-HT and 5-HIAA by about 70%. Isoprenaline…

Adrenoceptor- and cholinoceptor-mediated mechanisms in the regulation of 5-hydroxytryptamine release from isolated tracheae of newborn rabbits

1996

Abstract 1. Isolated tracheae of newborn rabbits were incubated in vitro and the outflow of 5-hydroxytryptamine (5-HT) was determined by h.p.l.c. with electrochemical detection. Evidence has previously been provided that this 5-HT outflow derives from neuroendocrine epithelial (NEE) cells of the airway mucosa. 2. Phenylephrine (1, 10 and 30 microM) enhanced the outflow of 5-HT by 80, 290 and 205%, respectively. 5-HT outflow evoked by 10 microM phenylephrine was not affected by the presence of the neurotoxin tetrodotoxin (1 microM). 3. Rauwolscine, ARC 239 (an alpha(2B)-adrenoceptor preferring antagonist), yohimbine and prazosin antagonized the effect of 10 microM phenylephrine in a concentr…

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…

Regulation of cell-to-cell communication in non-tumorigenic and malignant human prostate epithelial cells.

2002

BACKGROUND Gap-junction-mediated intercellular communication (GJIC) is required for normal development and tissue homeostasis. However, the role of GJIC in human prostate carcinogenesis and progression remains ill-defined. METHODS The ability of hormones, anti-hormones, and the anti-hypertensive drug, forskolin, to restore GJIC in non-tumorigenic (RWPE-1 and PWR-1E) and malignant (RWPE-2, LNCaP, DU-145) human prostate epithelial cell lines, was examined by Scrape-Loading/Dye Transfer (SL/DT) and Fluorescence Recovery After Photobleaching (FRAP) methods using an Ultima laser cytometer. RESULTS Results from both assays show that PWR-1E, RWPE-2, LNCaP, and DU-145 cells have weak or absent GJIC…

Inhibitory effects of indicaxanthin on mouse ileal contractility: analysis of the mechanism of action.

2011

Recently, we have showed that indicaxanthin, the yellow betalain pigment abundant in the fruit of Opuntia ficus indica, has remarkable spasmolytic effects on the intestinal contractility in vitro. Thus, the purpose of the present study was to investigate the mechanism of action underlying the observed response. We used organ bath technique to record the mechanical activity of the mouse ileum longitudinal muscle and ELISA to measure the levels of cAMP. Indicaxanthin induced inhibitory effects on spontaneous mechanical activity, which were unaffected by indomethacin, a non-selective inhibitor of cycloxygenase; 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one, a selective inhibitor of nitric oxide-…

Cardiac effects of isoliquiritigenin

1997

The effects of isoliquiritigenin on force of contraction (Fc), L-type Ca2+ current (I(Ca)) and intracellular Ca2+ concentration ([Ca2+]i) were investigated in rat ventricular heart muscle. Isoliquiritigenin increased Fc and I(Ca) and, after longer exposure times, resting tension and [Ca2+]i. The effect of isoliquiritigenin (100 microM) on I(Ca) was diminished by Rp-cAMPS (30 microM). 1H-[1,2,4]oxa- diazolo[4,3-a]quinoxalin-1-one (50 microM) did not influence the effects of isoliquiritigenin on Fc and I(Ca). The positive inotropic effects of isoprenaline and forskolin, but not of 3-isobutyl-1-methylxanthine, were potentiated by isoliquiritigenin (100 microM). In the presence of milrinone (10…