Search results for "guinea pig"

Peroxisome-proliferator-activated receptors as physiological sensors of fatty acid metabolism: molecular regulation in peroxisomes

2001

The enzymes required for the beta-oxidation of fatty acyl-CoA are present in peroxisomes and mitochondria. Administration of hypolipidaemic compounds such as clofibrate to rodents leads to an increase in the volume and density of peroxisomes in liver cells. These proliferators also induce simultaneously the expression of genes encoding acyl-CoA oxidase, enoyl-CoA hydratase-hydroxyacyl-CoA dehydrogenase (multifunctional enzyme) and thiolase (3-ketoacyl-CoA thiolase). All these enzymes are responsible for long-chain and very-long-chain fatty acid beta-oxidation in peroxisomes. Similar results were observed when rat hepatocytes, or liver-derived cell lines, were cultured with a peroxisome prol…

On the Function of the Spiral Prominence

1967

The suppression of hematic circulation of the internal auditory artery of a guinea-pig causes the necrosis of all anatomic formations of the cochlear duct, with the exception of the organ of Corti of the vestibular segment. The author confirms his hypothesis about the origin of the cochlear endolymph and thinks that the prominence provides the vegetative life of the organ of Corti.

Vitamin A deficiency increases noise susceptibility in guinea pigs.

1990

The effect of vitamin A deficiency in guinea pigs on noise-induced temporary threshold shift (TTS) was evaluated after short (15 min) acoustic overstimulation with a moderate (90 dB) broad-band white noise. Some guinea pigs were fed ad libitum a purified diet deficient in vitamin A (VAD group) until biochemical signs of deficiency occurred. A second, control group (VA group) received the same diet as well as 100 IU vitamin A daily by pharyngeal tube. Cochlear potentials were recorded by special computerized equipment using implanted electrodes. Before acoustic stimulation, a baseline value was determined with a test stimulus [90 dBA (A-filter according to usual DIN instructions)] correspond…

Ascorbic acid reduces noise-induced nitric oxide production in the guinea pig ear.

2008

Objectives: Noise-induced hearing loss can be caused, among other causes, by increased nitric oxide (NO) production in the inner ear leading to nitroactive stress and cell destruction. Some studies in the literature suggest that the degree of hearing loss (HL) could be reduced in an animal model through ascorbic acid supplementation. To identify the effect of ascorbic acid on tissue-dependent NO content in the inner ear of the guinea pig, we determined the local NO production in the organ of Corti and the lateral wall separately 6 hours after noise exposure. Study Design: Prospective animal study in guinea pigs. Methods: Over a period of 7 days, male guinea pigs were supplied with minimum (…

Formation and function of a complement-activating enzyme generated from factors of guinea pig serum and cobra venom

1971

An enzymatic complex can be formed by factors from guinea pig serum and cobra venom, which is able to activate C3 bypassing C1, C4 and C2. Formation and action of the enzyme are described. The action on C3 results in an activation of the terminal complement components and in membrane destruction provided suitable membrane receptors are available.

The Anaphylatoxic Peptide C3a of Guinea Pig Complement

1978

Abstract Highly purified guinea pig C3a was obtained after specific cleavage of isolated C3 by the alternative pathway enzyme VF-B in a one step procedure. It turned out to be a low molecular weight peptide with basic character (M.W. 9500; isoelectric point above 9.4). C3a represents an antigenetic determinant of its own in the native C3 molecule, different from the B determinant. Guinea pig C3a is resistant to 100°C for 10 minutes. Its smooth muscle contracting activity can be destroyed by trypsin and carboxypeptidase B. These findings indicate that guinea pig C3a is quite similar to human C3a.

SUBTYPES OF MUSCARINE RECEPTORS IN THE GUINEA-PIG ILEUM

1986

2-Substituierte Histamine 3. Mitt. über Struktur-Wirkungs-Beziehungen bei Histaminanaloga

1974

Es wurden verschiedene 2-substituierte Histaminderivate aus den entsprechenden 2-substituierten Imidazol-4-carbinolen dargestellt und am isolierten Ileum des Meerschweinchens auf ihre histaminartige Wirkung untersucht. 2-Substituted Histamines Some 2-substituted derivatives of histamine were synthesized from 2-substituted imidazole-4-carbinols. The histamine- or antihistamine — like activity of the resulting compounds was tested on isolated guinea pig ileum.

Struktur-Wirkungs-Beziehungen bei Histaminanaloga, 23. Mitt. Absolute Konfiguration und histaminartige Wirkung der enantiomeren α-Chlormethylhistamin…

1981

Es wird die histaminartige Wirksamkeit der enantiomeren α-Chlormethylhistamine (+)-2a und (−)-2a sowie der Nα-Methyl-α-chlormethylhistamine (+)-2b und (−)-2b am Ileum (H1) und Atrium (H2) des Meerschweinchens beschrieben und die absolute Konfiguration der Enantiomere abgeleitet. Structure-Activity Relationships of Histamine Analogues, XXIII: Absolute Configuration and Histamine-like Activity of the Enantiomeric α-Chloromethylhistamines and Nα-Methyl-α-chloromethylhistamines The histamine-like activities of the enantiomeric α-chloromethylhistamines (+)-2a and (−)-2a and of the Nα-methyl-α-chloromethylhistamines (+)-2b and (−)-2b on the guinea pig ileum (H1) and atrium (H2) are reported. The …

The Effects of Microelectrophoretically Applied Melatonin, Putative Transmitters, Thyroxine and Sex Hormones on the Electrical Activity of Pineal Cel…

1981

ABSTRACT The effects of microelectrophoretic application of melatonin, noradrenaline, acetylcholine, thyroxine, testosterone and oestrone on pineal cell electrical activity were evaluated. With the exception of acetylcholine and oestrone pineal cells showed a circadian rhythm in sensitivity to the application of the substances. It is apparent from these studies, that (1) transmitters and hormones can bring about direct changes in the firing frequency of pineal cells, (2) all pineal cells do not respond to these substances in the same way and (3) that melatonin either produced in the pineal organ or reaching the gland via the general circulation may be capable of directly influencing the cel…