摘要:

This study was conducted to determine if there is a difference in the calcium handling mechanism of the thoracic and abdominal aortic regions of the rabbit aorta. Isolated segments of aorta from both regions were studied in HEPES buffer at 37 °C and bubbled with 100% oxygen using identical procedures. Intracellular calcium levels were determined after segments had been exposed to 45Ca-labeled buffer during experimental procedures and subsequently washed with a ‘quench’ solution of zero calcium, 2 mM EGTA, and HEPES buffer, maintained at 0°C. The results suggest that the thoracic region is capable of taking up more calcium under resting conditions compared to the abdominal aorta. During stimulation with norepinephrine, both regions show significantly increased calcium influx rates after 10 min of exposure to the agonist, but only in the abdominal region is this effect maintained after 60 min of norepinephrine stimulation. Net (summation of calcium influx and efflux) intracellular calcium levels are significantly increased by norepinephrine in the thoracic but not in the abdominal aorta. Taken together, these data suggest that, compared to the thoracic aorta, the abdominal aorta may possess a more effective calcium efflux mechanism which may be able to fully compensate for the norepinephrine-stimulated increase in calcium i

ISSN:0031-7012    

DOI:10.1159/000138043

出版商:S. Karger AG    

年代:1985

数据来源: Karger

摘要:

The effect of ethanol ingestion on the uptake of labeled amino acids was studied in the in situ autoperfused dog liver. Ethanol was administered orally, as a 15 % water solution, in a dose of 4 g/kg body weight/day as the only source of water for 2 days. Amino acid uptake was measured in anesthetized dogs by means of the single-passage, multiple-tracer dilution technique. In control animals, hepatic uptake of 14C-glycine, 3H-α-aminoisobutyric acid (3H-AIB) and 3H-L-leucine were 50, 15 and 66%, respectively. In the ethanol-treated dogs, glycine and AIB uptake was reduced by 70 and 63 %, respectively. L-leucine uptake was reduced by only 23%. The plasma concentration of the naturally occurring amino acids was significantly increased after ethanol treatment, probably due to a reduced influx into hepatocytes. Simultaneous measurements of hemodynamic parameters showed a significant increase in the portal vein pressure of ethanol-treated animals, whereas the portal vein blood flow and hepatic extracellular volume were unaffected

ISSN:0031-7012    

DOI:10.1159/000138044

出版商:S. Karger AG    

年代:1985

数据来源: Karger

摘要:

Chronic oral treatment of young female Fischer rats with 25 mg/kg Δ9-tetrahydrocannabinol (THC) per day inhibited aminopyrine demethylation and significantly increased benzo[a]pyrene oxidation by the liver. THC treatment also elevated serum corticosterone levels and produced a significant loss of body weight. The weight loss was not due to vehicle or food intake (pair-feeding). Pair-feeding did, however, produce a stimulation of both mixed function oxidase pathways as well as a marked elevation in serum corticosterone levels. The results indicate that THC has a differential effect on mixed function oxidase pathways in the liver that is not directly related to food intake or corticosterone levels

ISSN:0031-7012    

DOI:10.1159/000138045

出版商:S. Karger AG    

年代:1985

数据来源: Karger

摘要:

Morphine potentiated the ulcerogenic activity of indometacin in a dose-dependent manner when administered subcutaneously (2.5–7.5 mg/kg). However, in the case of intracerebroventricular administration, morphine failed to exert any potentiating action. Atropine (0.5 mg/kg, s.c.) and cimetidine (12.5–25 mg/kg, s.c.) decreased the ulcerogenic activity of indometacin, and the combination of indometacin/morphine in about the same degree. However, the reduced ulcerogenic activity of indometacin after atropine or cimetidine treatment could still be enhanced by morphine if it was added to the combination of indometacin/atropine or indometacin/cimetidine. Since the potentiating action of morphine was completely blocked by naloxone (1 mg/kg), this action of morphine might be mediated via opiate recept

ISSN:0031-7012    

DOI:10.1159/000138046

出版商:S. Karger AG    

年代:1985

数据来源: Karger

摘要:

The effect of food intake and gut bacterial flora on gastrointestinal lesions caused by oral indometacin (IND) was studied in rats. A dose of 10 mg/kg IND caused no intestinal lesions when the animals were starved before and after treatment; it produced moderate lesions when the animals were continuously fed and maximal lesions when the animals were fed in the postdrug period after starvation in the predrug period. Under germ-free conditions, 15 mg/kg IND induced significantly less intestinal lesions than under specific pathogen-free conditions. The differences in the magnitude of intestinal lesions under the varying feeding and maintenance conditions were not associated with different IND concentrations in the jejunal mucosa. The dose of 10 mg/kg IND produced most gastric lesions when the animals were previously starved for 24 h and subsequently fed, medium lesions in continuously starved animals and only a few lesions in animals fed before and after IND. The disposition of IND from the gastric mucosa did not differ under the different feeding conditions. As the dose of IND is high enough to inhibit prostaglandin synthesis, it was concluded that additional factors are important for the development of gastrointestinal lesions caused by IND. Secondary bile acids in conjunction with IND are important for the development of intestinal lesions, while gastric acid influences the intensity of gastric lesions.

ISSN:0031-7012    

DOI:10.1159/000138047

出版商:S. Karger AG    

年代:1985

数据来源: Karger

摘要:

This study involved a randomized parallel groups comparison of the effects of aspirin formulated as enteric-coated granules (25 subjects) or as buffered tablets (26 subjects) with that of a lactose placebo (5 subjects), on the gastric and duodenal mucosa, as determined by endoscopic examination 2 h after a fasting single 975-mg dose. A grading scale of 0 (no damage) to 4 (severe damage) was used. The granule formulation produced a statistically significant (p < 0.05) lower severity (mean 0.40 ± 0.58 vs. 3.00 ± 0.94) and incidence (36% of subjects vs. 100%) of gastric lesions than the buffered aspirin formulation. None of the lesions produced by the granule formulation or the placebo was considered clinically significant by the blinded endoscopist, whereas 17 subjects on the buffered formulation (65%) had clinically meaningful stomach damage. The incidence of duodenal lesions was minimal and comparable for the two formulation

ISSN:0031-7012    

DOI:10.1159/000138048

出版商:S. Karger AG    

年代:1985

数据来源: Karger

摘要:

The protective effect of cimetidine, ranitidine and a newer H2-receptor antagonist, mifentidine (proposed INN), on models of gastric and duodenal damage, caused by activation of H2 receptors, was studied. Gastric erosions were induced in rats by intravenous dimaprit (100 mg/kg) while duodenal damage was investigated in guinea pigs following subcutaneous administration of dimaprit (2 mg/kg, 6 doses). All the compounds reduced or abolished gastric and duodenal damage in rats and guinea pigs, mifentidine being more potent than both cimetidine and ranitidine. The antiulcer effect of the H2-receptor antagonists was related to the dose and to their ability to inhibit dimaprit-induced gastric acid secretion. The duration of action proved to be different for the three compounds. According to the two dosing schedules adopted to evaluate the duration of action, mifentidine, compared to cimetidine and ranitidine, required considerably lower oral dosages to display its protective effect.

ISSN:0031-7012    

DOI:10.1159/000138049

出版商:S. Karger AG    

年代:1985

数据来源: Karger

摘要:

The new synthetic tripeptide, p-fluoro-L-phenylalanyl-m-bis-(2-chloroethyl)- amino-L-phenylalanyl-methionine ethylester hydrochloride, PTT.l 19, an alkylating agent, is currently undergoing preclinical trials as an antineoplastic agent. The molecular composition, C29H39N4O4SCl2F, was confirmed by desorption chemical ionization mass spectrometry with accurate mass measurement. A high-performance liquid chromatographic technique was developed for the quantification of PTT.l 19 in cell culture medium and serum. Incubation of 5 × 105 mammary tumor cells (MJY-α)/ml tissue culture medium with 25 μg PTT. 119/ml for 60 min (37°C) removed 68% of the tripeptide from the medium. This corresponds to an uptake of 51 fmol PTT.119/tumor cell. Cell death, assessed 5 days after treatment, was directly proportional to the time-dependent removal of PTT.119 from the cell culture med

ISSN:0031-7012    

DOI:10.1159/000138050

出版商:S. Karger AG    

年代:1985

数据来源: Karger

摘要:

The possible pre- and postsynaptic effects of tetraethylammonium (TEA; a potassium ion channel blocker) have been examined in the isolated chick neuromuscular junction. The presynaptic effect of TEA was studied by investigating its effect on the uptake of tritiated choline, 3H-methyl choline, which was taken as an index of acetylcholine (ACh) release. The postsynaptic effect of TEA was investigated using solutions containing no calcium ions and/or calcium antagonist lanthanum. TEA increased the uptake of tritiated choline by a factor of 10. Although the contracture produced by TEA was greatly reduced by lanthanum (0.1–1 μM), it still persisted in the calcium-free Krebs soluti

ISSN:0031-7012    

DOI:10.1159/000138051

出版商:S. Karger AG    

年代:1985

数据来源: Karger