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1.
Developmental Patterns of Catechol-O-Methyltransferase in Genetically Different Rat Strains: Enzymatic and Immunochemical Studies 总被引:4,自引:4,他引:0
D. J. Goldstein R. M. Weinshilboum J. H. Dunnette C. R. Creveling 《Journal of neurochemistry》1980,34(1):153-162
Abstract: Catechol- O -methyltransferase (COMT) activity in the liver and kidneys of adult Fischer-344 (F-344) rats is only half of that in the same organs of Wistar-Furth (W-F) rats. The trait of low COMT activity in these animals is inherited in an autosomal recessive fashion. A comprehensive study of patterns of change in COMT activity during growth and development was performed to determine whether "temporal gene" effects might play a role in the inherited differences in enzyme activity present in adult animals. The COMT activity expressed per mg protein in liver and kidneys of newborn F-344 rats is only 50–60% of that in the same organs of W-F animals. The liver and the kidneys of newborn rats of both strains have COMT activity an order of magnitude higher than those in brain, heart, or blood. In addition, in both strains there are much larger increases in liver and kidney COMT activities during growth and development (5–10 fold) than in blood, brain, or heart (one- to twofold). Immunotitration with antibodies against rat COMT demonstrates that differences in immunoreactive COMT parallel differences in COMT activity, both between strains and within strains during growth and development. However, when the temporal patterns of change in enzyme activities in the liver and the kidneys of the two strains of rat are compared at multiple times during growth and development, no differences in the patterns are present. These results make it unlikely that temporal gene effects can explain the inherited differences in COMT activity in liver and kidneys of F-344 and W-F rats. 相似文献
2.
急性脑梗死约占全部脑卒中的70%,病死率和致残率高,且极易复发。但目前针对急性脑梗死在时间窗内溶栓、抗凝等治疗手段不能从根本上切实有效地修复受损脑组织,且伴有出血等风险。寻找脑梗死形成发展的原因并予以治疗迫在眉睫。酸中毒是引起缺血性脑损伤的重要机制。大量实验研究表明,酸中毒能加重神经元的缺血性损伤,且其梗死面积与酸中毒的程度直接相关。但缺血产生的酸中毒如何引起神经元损伤的确切机制尚不明确。最近研究发现酸中毒能激活一种在中枢及周围神经中广泛存在的膜通道,即酸敏感离子通道,它对Ca2+通透,能引起细胞内Ca2+超载,同时能激活胞内酶引起细胞内蛋白质、脂类及核酸的降解,加重缺血后脑损伤。本文就酸敏感离子通道1a与脑梗死做一综述。 相似文献
3.
Behavioral and physiological effects of chronic 2,450-MHz microwave irradiation of the rat at 0.5 mW/cm2 总被引:2,自引:0,他引:2
J A D'Andrea J R DeWitt O P Gandhi S Stensaas J L Lords H C Nielson 《Bioelectromagnetics》1986,7(1):45-56
Adult male Long-Evans rats were intermittently exposed to 2450 MHz CW microwaves at an average power density of 0.5 mW/cm2 for 90 days. The resulting SAR was 0.14 W/kg (range 0.11 to 0.18 W/kg). The animals were exposed 7 h/day, 7 days/wk, for a total of 630 h in a monopole-above-ground radiation chamber while housed in Plexiglas holding cages. Daily measures of body mass and food and water intake indicated no statistically significant effects of microwave exposure. Monthly assessment of reactivity to electric footshock, levels of cholinesterase and sulfhydryl groups in blood, and 17-ketosteroids in urine revealed no reliable differences between 14 sham-exposed and 14 microwave-exposed rats. After the 90 days of exposure, seven rats, randomly chosen from each group, were assessed for open-field behavior, shuttlebox performance, and schedule-controlled (IRT schedule) lever pressing for food pellets. Statistically significant differences between microwave-exposed and sham-exposed rats were observed in shuttlebox performances and lever pressing. Post mortem measures of mass of several organs and microscopic examination of adrenal tissue revealed no differences between the two groups of animals. 相似文献
4.
Summary When the body temperature of rats is elevated to 42°C, four heat shock proteins, with the molecular weights of 70000, 71000, 85000, and 100000 (hsp 70, hsp 71, hsp 85, and hsp 100, respectively), are induced in various tissues of rats (Fujio et al., J Biochem 101, 181–187, 1987). Heat shock proteins are induced by various stresses other than heat in varieties of cultured cells, so we studied whether heat shock proteins are induced in intact rats by different treatments. Analysis of the translation products of poly(A) + RNA isolated from the livers of rats recovering from ischemia of the liver showed that mRNAs for hsp 70, hsp 71, and hsp 85 were induced. These hsp-mRNAs were also induced in the livers of rats 6 h after a partial hepatectomy, and had returned to control levels 24 h after the surgery. These results suggested that heat shock proteins have not only the function of protection against various stresses but also physiological functions in the normal growth and development of animals. 相似文献
5.
Summary The wall of the cerebral aqueduct was examined in 20 male rats at the light- and electron-microscopic levels. Disorder in ciliary orientation was occasionally seen in ordinary ependymal cells. Ependymal cells possessing intracellular cysts of 5 to 30 urn in diameter were observed within and beneath the aqueductal ependyma in all animals examined. Light-microscopic reconstruction from serial, 10-m thick frontal sections revealed an extensive distribution of cystic ependymal cells (CECs), especially along the ependymal ridges in the rostral half of the aqueduct, and along the dorsal region of the aqueductal lining in the caudal half. Both cystic and surface membranes of CECs bore microvilli and cilia. Ectopic ependymal cells (EECs) characterized by densely packed microvilli, well-developed intermediate junctions and cilia, but without cysts, were situated in the subependymal region adjacent to a CEC or another EEC. The ependymal ridges were long, narrow and sporadically stratified ependymal linings extending rostrocaudally and bilaterally along the aqueductal surface. Tanycyte-like cells filled the surface region of the ridge, and CECs and EECs were frequently seen in the core. Intraventricularly injected microperoxidase was detected among densely packed microvilli but not in the cystic lumina of CECs, indicating that EECs and CECs are distinct entities. 相似文献
6.
Dr. Peter D. Ottosen Jens R. Nyengård N. O. Jacobsen Sten Christensen 《Cell and tissue research》1987,249(2):311-315
Summary Rats were given a lithium-containing diet (40 mmol/kg) to Study the effect of lithium on the structure of collecting ducts from the inner stripe of the outer medulla. The results show that there is a significant increase in the volume density of collecting ducts already after one week on this diet. The volume density of both intercalated and principal cells increases, whereas the volume density of mitochondria in the cytoplasm increases in the intercalated cells only. The increased volume of both principal and intercalated cells seems to be part of a general hyperplasia and hyperactivity of the collecting duct, which may in some way be related to the effects of lithium on vasopressinmediated water transport. The specific changes in the intercalated cells may be a consequence of the effects of lithium on distal nephron potassium and hydrogen ion transport in the distal nephron. 相似文献
7.
Chronic hyperphenylalaninemia maintained with the aid of a suppressor of phenylalamine hydroxylase, -methylphenylalanine, increases the glycine concentration and the phosphoserine phosphatase activity of the developing rat brain but not that of liver or kidney. Similar increases occur after daily injections with large doses of phenylalanine alone, while tyrosine, isoleucine, alanine, proline, and threonine, were without effect. Treatment with methionine, which increases the phosphoserine phosphatase activity of the brain and lowered that of liver and kidney, left the cerebral glycine level unchanged. When varying the degrees of gestational or early postnatal hyperphenylalaninemia, a significant linear correlation was found between the developing brains' phosphoserine phosphatase and glycine concentration. Observations on the uptake of injected glycine and its decline further indicate that coordinated rises in the brain's phosphoserine phosphatase and glycine content associated with experimental hyperphenylalaninemia denote a direct impact of phenylalanine on the intracellular pathway of glycine synthesis in immature animals. 相似文献
8.
Douglas M. Templeton Anna Paudyn Andrew D. Baines 《Biological trace element research》1989,22(1):17-33
Interest in the biological behavior of a growing number of elements, along with increasing recognition of the importance of interactions among them, demands a versatile and reliable technique for multielement analysis of biological samples. Significant improvements over the sensitivity achieved with conventional inductively coupled plasma (ICP) optical emission spectrometries have been realized with the introduction of quadrupole mass spectrometry (MS) for detection of ions in the plasma. The hybrid technique of ICP-MS promises to be a method of rapid multielement analysis, at detection limits that approach or surpass those of other technologies. However, the application of ICP-MS to analyses of biological interest is truly in its infancy. Here we report the use of ICP-MS for the determination of more than 30 elements of biological interest in a tissue and a biological fluid (rat liver and serum, respectively). Experimental values of the elements serve as a basis for discussion of analytical protocols, performance criteria, and certain problems peculiar to ICP-MS. 相似文献
9.
A single intraperitoneal injection of DL-methionine (500 mg/kg body wt.) to adult male Wistar rats was shown to significantly
induce all the components of the hepatic microsomal mixed function oxidase system such as NADPH cytochrome C reductase activity,
cytochromes P-450 and b5, as well as activities of drug metabolizing enzymes such as aminopyrine demethylase and uridine 5′ -diphosphate-glucuronosyltransferase.
Combined administration of nicotinamide (250 mg/kg body wt.) and DL-methionine (500 mg/kg body wt.) was shown to bring about
an additional increase (25-30%) in the activities of these enzymes as compared to their induction on independent administration
of the two endobiotics. In rats bearing Yoshida sarcoma (ascites) tumour as well as in normal rats injected with serum from
tumour bearing animals, the decreased activities of hepatic mixed function oxidases could be restored to their normal levels
by administration of DL-methionine (500 mg/kg body wt.) to these rats. Whereas actinomycin D (1 mg/kg body wt.) had no effect
on the increased incorporation of [14C] labelled leucine into microsomal proteins following administration of nicotinamide, the enhanced incorporation of the label
following DL-methionine administration was completely inhibited by the same dose of actinomycin D. Administration of cycloheximide
(0·5 mg/kg body wt.) to rats could completely inhibit the increased incorporation of [14C] leucine into hepatic microsomal proteins following independent administration of nicotinamide and DL-methionine. Similar
inhibitory pattern with actinomycin D and cycloheximide was also demonstrated in case of induction of NADPH cytochromeC reductase activity by both these endobiotics. 相似文献
10.
Hiroshi Yao Hiroaki Ooboshi Seizo Sadoshima Kentaro Takano Setsuro Ibayashi Masatoshi Fujishima 《Neurochemical research》1990,15(5):547-549
To determine the level of cerebral blood flow reduction which causes striatal dopamine release, extracellular dopamine and cerebral blood flow was simultaneously determined using in vivo brain dialysis and a hydrogen clearance method, respectively, in the striatum of spontaneously hypertensive rats, before and during experimental cerebral ischemia. The ischemic flow threshold for neurotransmitter dopamine release was found to be 20% of the resting value or 8–10 ml/100g/min of cerebral blood flow, being similar to those for energy and membrane failures. 相似文献