Search results for "Guinea Pig"
showing 10 items of 372 documents
Bronchodilator and anti-inflammatory activities of SCA40: studies in human isolated bronchus, human eosinophils, and in the guinea-pig in vivo.
1998
There is currently interest in the use of inhibitors of cyclic nucleotide phosphodiesterases (PDE) as potential anti-asthma agents. In this study we examined the effects of SCA40 (6-bromo-8-methylaminoimidazol-[1,2-a] pyrazine-2-carbonitrile), a preferential inhibitor of PDE 3 also endowed with PDE 4 and 5 inhibitory activities, on isolated bronchus and eosinophil functions and in an animal model of asthma. SCA40 (1 nM-0.1 mM) produced concentration-dependent inhibition of spontaneous and stimulated tone of human isolated bronchus and reached a maximal relaxation similar to that of theophylline (3 mM). The potency (-log EC50 values) of SCA40 against spontaneous tone (6.52 +/- 0.10) was grea…
Mechanisms of C-reactive protein-induced blood-brain barrier disruption.
2009
Background and Purpose— Increased mortality after stroke is associated with brain edema formation and high plasma levels of the acute phase reactant C-reactive protein (CRP). The aim of this study was to examine whether CRP directly affects blood–brain barrier stability and to analyze the underlying signaling pathways. Methods— We used a cell coculture model of the blood–brain barrier and the guinea pig isolated whole brain preparation. Results— We could show that CRP at clinically relevant concentrations (10 to 20 μg/mL) causes a disruption of the blood–brain barrier in both approaches. The results of our study further demonstrate CRP-induced activation of surface Fcγ receptors CD16/32 fo…
Molecular anatomy of the neuro-immune connection.
1991
Light microscopic immunohistochemistry was employed to elucidate and compare the presence, distribution, and coexistence of various peptides, neuroendocrine markers and enzymes of the catecholamine pathway in nerves supplying lymphoid tissues in a variety of mammalian species. All lymphoid organs and tissues receive innervation by fibers containing dopamine-beta-hydroxylase and/or tyrosine hydroxylase, neural markers like protein gene product 9.5, synaptophysin and neurofilament and a varied spectrum of peptides. The prominent peptides were tachykinins (substance P, neurokinin A), calcitonin gene-related peptide (CGRP), neuropeptide Y (NPY), and vasoactive intestinal polypeptide/peptide his…
Studies on the mechanism of PMN activation III. by lymphokines.
1983
The influence of a guinea pig lymphokine preparation on the oxidative metabolism of human and guinea pig granulocytes of various sources was investigated. A dose-dependent increase of the oxidative burst following lymphokine challenge was observed. It occurred in unstimulated guinea pig peripheral polymorphonuclear leukocytes (PMN) and in prestimulated PMN obtained from the peritoneal cavity after glycogen injection as well. The lymphokine effect on the oxidative metabolism is not species-restricted because the guinea pig lymphokine preparation elicits an oxidative burst in human PMN, too. The increase caused by lymphokines is nearly of the same order of magnitude as that obtained with zymo…
The influence of Ca2+ antagonists on the ciliary activity of the guinea pig trachea.
1990
The ciliary activity of the guinea pig tracheal respiratory epithelium was measured using a photoelectric device. Fourteen animals were administered 75 mg diltiazem/kg body weight 2 days, 1 day and 4 h prior to the investigation. Thirteen animals served as controls. In the pretreated group, the mean ciliary stroke frequency (13.4 +/- 3.0 Hz) was significantly lower (P = 0.02) than in the control group (16.6 +/- 3.7 Hz). The application of aerosolized 0.3 mmol/l nifedipine solution on the tracheal preparations of the control animals also significantly reduced the stroke frequency (P = 0.02). The ciliary activity never dropped beyond a frequency of about 8 Hz. The most probable interpretation…
Rolipram inhibits airway microvascular leakage induced by platelet-activating factor, histamine and bradykinin in guinea-pigs.
1993
Abstract Rolipram (0·1–1000 μg kg−1, i.v.) reduced the increase in microvascular permeability induced by platelet-activating factor (PAF; 50 ng kg−1, i.v.) at different sites of the guinea-pig airways. Rolipram (1–100μg kg−1, i.v.) inhibited histamine (30μg kg−1, i.v.)-and bradykinin (0·3 μg kg, i.v.)-induced airway microvascular leakage. These effects of rolipram were obtained at doses which inhibit histamine (7–20 μg kg−1 min−1)-induced bronchoconstriction (IC50 = 3 ± 1 μg kg, i.v.) without depressing arterial blood pressure in the guinea-pig. Aminophylline (50 mg kg−1) did not change the effect of PAF. The anti-exudative effect of rolipram is of potential therapeutic value in asthma.
ROLIPRAM INHIBITS PAF-INDUCED AIRWAY MICROVASCULAR LEAKAGE IN GUINEA-PIG - A COMPARISON WITH MILRINONE AND THEOPHYLLINE
1992
The effects of 3 phosphodiesterase (PDE) inhibitors, rolipram (PDE IV), milrinone (PDE III) and theophylline (non-selective) on PAF (50 ng kg-1; iv)-induced airway vascular leakage have been evaluated in guinea-pigs. Rolipram (3-300 micrograms kg-1; iv) reduced the increase in permeability induced by PAF at all airway levels whereas milrinone (10-1000 micrograms kg-1; iv) and theophylline (30 mg kg-1; iv) were without effects. The anti-leakage activity of rolipram may be of therapeutic value in asthma.
Epithelium-derived inhibition of [3H]acetylcholine release from the isolated guinea-pig trachea
1990
To investigate presynaptic, regulatory mechanisms on parasympathetic nerve fibres innervating the airways, the release of newly-synthesized [3H]acetylcholine from the isolated trachea was studied. Reverse phase HPLC followed by liquid scintillation spectrometry was used to separate and quantify the radioactive compounds choline, phosphorylcholine and acetylcholine in the incubation medium and the tissue. During the incubation of the tracheae with [3H]choline a significant synthesis of [3H]acetylcholine (35,000 dpm/preparation) and [3H]phosphorylcholine (500,000 dpm/preparation) occurred. In epithelium-deficient tracheae the formation of [3H]phosphorylcholine was enhanced, whereas the conten…
Substance P inactivation by transglutaminase in vitro.
1992
Gamma(glutamyl5)spermine derivative of substance P (Spm-SP) was synthesized in vitro in the presence of purified guinea pig liver transglutaminase and Ca2+. The spermine adduct of the neuropeptide was purified by HPLC on a reversed-phase column and characterized by fast atom bombardment mass spectrometry. The biological activities of Spm-SP were tested by assaying, in comparison with substance P, its ability to induce both the contractions of smooth muscle in vitro and the edema formation in vivo. Spm-SP was shown not to elicit contractile responses in the isolated rat stomach strip and duodenum and not to antagonize the spasmogenic effect evoked by the native neuropeptide. Furthermore, Spm…
Electrical responses of homing pigeon and guinea pig Purkinje cells to pineal indoleamines applied by microelectrophoresis
1984
The effects of microelectrophoretically applied melatonin (aMT), 5-methoxytryptophol (ML), 5-hydroxytryptophol (HL) and noradrenaline (NA) on the electrical activity of cerebellar Purkinje and other cells during both day- and nighttime were studied in urethane-anesthetized intact and pinealectomized homing pigeons and guinea pigs.