Search results for "guinea"
showing 10 items of 412 documents
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 …
Neuropeptide Y (NPY)-like immunoreactivity in the guinea pig pineal organ.
1986
Relatively little is known about mammalian pineal neuropeptides. In the present study neuropeptide Y-like immunoreactivity (NPY-LI) was examined in the guinea pig pineal gland. NPY-LI was restricted to few intrapineal nerve fibers of faint fluorescence intensity. They showed no preferential localization with regard to the different pineal portions. As catecholaminergic fibers are abundant in the guinea pig pineal gland, the scarcity of NPY-LI fibers indicates that in the pineal colocalization of noradrenaline and NPY-LI is not a regular feature, in contrast to other organs. The possibility exists that in the pineal NPY-LI fibers are not of peripheral sympathetic but of central origin.
Die Aufnahme von Methylsulfat-Ionen in die Vorhofsmuskulatur von Meerschweinchen
1963
The uptake of methylsulfate ions by isolated guinea pig atria and auricles has been studied.
Enhancement of guinea-pig intestinal peristalsis by blockade of muscarinic M1-receptors
1988
1. The effects of pirenzepine and hyoscine on the peristaltic reflex were investigated in the guinea-pig isolated small intestine. Peristalsis was induced by raising the intraluminal pressure and the volume of fluid propelled was taken as a measure of the efficiency of peristaltic activity. 2. Low concentrations of pirenzepine (0.1-1 nM) and of hyoscine (0.01 nM) significantly enhanced peristalsis, whereas larger concentrations of both drugs caused inhibition. Pirenzepine was about 6 times less potent than hyoscine in increasing peristalsis, but was about 100 times less potent in inhibiting it. 3. Neither tolazoline (1 microM) nor naloxone (0.3 microM) affected the stimulatory action of pir…
Immunoelectron microscopic localization of nitric oxide synthase III in the guinea pig organ of Corti
1998
Nitric oxide synthase III (NOS III) was identified in the guinea pig cochlea on an ultrastructural level using a post-embedding immunolabeling procedure. Ultrathin sections of London Resin (LR) White-embedded specimens were incubated with various concentrations of a commercially available antibody to NOS III and the immunoreactivity visualized by a gold-labeled secondary antibody. Analysis of ultrathin sections of the organ of Corti in the second turn of the cochlea showed that NOS III could be localized in the endothelial cells of the blood vessels under the basilar membrane, which was comparable to its location in similar cells types in various biological systems. Besides this, NOS III wa…
Morphologic Damage and Changes of Intracellular Calcium-Binding Sites after Acute Noise Trauma in the Organ of Corti of the Guinea Pig
1993
In guinea pigs, an acute acoustic trauma was created by 6 consecutive gunshots. The sound pressure at the ear drum was 156 +/- 4 dB, the frequency maximum was between 4 and 6 kHz. Sixty hours after the noise trauma, the animals were decapitated, and the cochleae were prepared for microscopic analysis of the resulting trauma to the organ of Corti. During the process of fixation, the potassium-pyroantimonate precipitation reaction was performed to localize calcium-binding sites. The pattern of cell morphology and the distribution of calcium-binding sites was compared to that of normal control animals. Morphologic changes of the cells in the organ of Corti correlated with changes of the cellul…
Isolation and Characterization of Epidermal DNA and RNA from Guinea Pig Skin
1971
DNA and RNA were isolated from mammalian epidermis in a relatively small scale procedure. The high purity and native state of the DNA isolated is reflected by its molar absorptivity E (P), its thermal hyperchromicity and its hyperchromicity upon DNase treatment and by its sedimentation profile as well as by its profile in a cesium chloride density gradient. The very low content of protein and RNA, as well as the data of DNA determination, indicate that this method permits the isolation of a highly purified product. This is further substantiated by the determination of UV absorption spectra and by analysis of the base composition.The mammalian skin DNA showed the following properties: Mol. w…
Muscarinic Properties of Compounds Related to Arecaidine Propargyl Ester
2011
A series of new analogues of the arecaidine propargyl ester (CAS 35516-99-5, APE, 1a) with alcohols consisting of 4 or 5 carbon atoms were investigated at muscarinic receptor subtypes. The muscarinic activity of the quaternary and tertiary salts of the APE-related compounds were assayed on the isolated guinea-pig ileum (M 3 receptor subtype) and guinea-pig left atria (M 2 receptor subtype) as well as on rabbit isolated vas deferens (M 1 receptor subtype). The structural variations made in the APE molecule, replacing the triple bond in the ester side chain with structures such as double bond, an allene moiety, a single bond, a cyclopropyl group or two triple bonds should alter the selectivit…
Sinusoidal endothelial liver cells in vitro release endothelin — Augmentation by transforming growth factorβ and Kupffer cell-conditioned media
1991
Endothelin is the most potent vasoconstrictor peptide known today. Using a radioimmunoassay for endothelin, we measured immunoreactive endothelin in culture media of guinea pig sinusoidal endothelial liver cells and human umbilical vein endothelial cells. A time-dependent release of immunoreactive endothelin by confluent sinusoidal endothelial liver cells in culture was found. Sinusoidal endothelial liver cells produced similar amounts of immunoreactive endothelin as umbilical vein endothelial cells, about 900 pg/microgram DNA per 24 h. In the presence of transforming growth factor beta a dose-dependent increase of immunoreactive endothelin release was measured. The maximal increase of 50% …
Pharmacological analysis of the responsiveness of guinea-pig lung parenchymal strip to dopamine
1984
Abstract Responses to dopamine were examined in the guinea-pig isolated lung parenchymal strip. Complete cumulative concentration-response curves to dopamine exhibited a biphasic pattern with a small initial contraction at concentrations below 10(-5) M followed by a dose-dependent relaxation at higher concentrations. Phentolamine (10(-5) M) completely abolished the contractile component and enhanced sensitivity and maximal relaxation to dopamine. In the presence of phentolamine, propranolol antagonized the dopamine-induced relaxation (pA2 = 8.54 +/- 0.07). In the presence of propranolol (10(-6) M), dopamine produced a dose-related contraction displaced to the right by phentolamine. Incubati…