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121.
1. The development of synaptic transmission and indicators of short- and long-term plasticity was studied by recording from areas CA1 and CA3 upon activation of monosy- naptic excitatory inputs in rat hippocampal brain slices obtained from Wistar rats of different ages.2. Although population field excitatory postsynaptic potentials (fEPSPS) are small in animals at postnatal day 10 (P10), both areas already exhibited short-term [posttetanic potentiation (PTP) and paired pulse potentiation (PPF)] and long-term [long-term potentiation (LTP)] plastic responses.3. The amplitudes of the fEPSP and LTP increased with age in both regions, but peaked at P30 in CA3 while they were still increasing at the oldest age studied (P60) in CA1. In CA3, but not CA1, LTP at P60 was less than at P30.4. PTP did not show clear alterations with age in either region. PPF decreased with age in CA1 but not CA3. 相似文献
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Hussain MB MacAllister RJ Hobbs AJ 《American journal of physiology. Heart and circulatory physiology》2001,280(3):H1151-H1159
Nitric oxide (NO) and atrial natriuretic peptides (ANP) activate soluble (sGC) and particulate guanylate cyclase (pGC), respectively, and play important roles in the maintenance of cardiovascular homeostasis. However, little is known about potential interactions between these two cGMP-generating pathways. Here we demonstrate that sGC and pGC cooperatively regulate cGMP-mediated relaxation in human and murine vascular tissue. In human vessels, the potency of spermine-NONOate (SPER-NO) and ANP was increased after inhibition of endogenous NO synthesis and decreased by prior exposure to glyceryl trinitrate (GTN). Aortas from endothelial NO synthase (eNOS) knockout (KO) mice were more sensitive to ANP than tissues from wild-type (WT) animals. However, in aortas from WT mice, the potency of ANP was increased after pretreatment with NOS or sGC inhibitor. Vessels from eNOS KO animals were less sensitive to ANP after GTN pretreatment, an effect that was reversed in the presence of an sGC inhibitor. cGMP production in response to SPER-NO and ANP was significantly greater in vessels from eNOS KO animals compared with WT animals. This cooperative interaction between NO and ANP may have important implications for human pathophysiologies involving deficiency in either mediator and the clinical use of nitrovasodilators. 相似文献
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Intersectin can regulate the Ras/MAP kinase pathway independent of its role in endocytosis 总被引:6,自引:0,他引:6
Tong XK Hussain NK Adams AG O'Bryan JP McPherson PS 《The Journal of biological chemistry》2000,275(38):29894-29899
We previously identified intersectin, a multiple EH and SH3 domain-containing protein, as a component of the endocytic machinery. Overexpression of the SH3 domains of intersectin blocks transferrin receptor endocytosis, possibly by disrupting targeting of accessory proteins of clathrin-coated pit formation. More recently, we identified mammalian Sos, a guanine-nucleotide exchange factor for Ras, as an intersectin SH3 domain-binding partner. We now demonstrate that overexpression of intersectin's SH3 domains blocks activation of Ras and MAP kinase in various cell lines. Several studies suggest that activation of MAP kinase downstream of multiple receptor types is dependent on endocytosis. Thus, the dominant-negative effect of the SH3 domains on Ras/MAP kinase activation may be indirectly mediated through a block in endocytosis. Consistent with this idea, incubating cells at 4 degrees C or with phenylarsine oxide, treatments previously established to inhibit EGF receptor endocytosis, blocks EGF-dependent activation of MAP kinase. However, under these conditions, Ras activity is unaffected and overexpression of the SH3 domains of intersectin is still able to block Ras activation. Thus, intersectin SH3 domain overexpression can effect EGF-mediated MAP kinase activation directly through a block in Ras, consistent with a functional role for intersectin in Ras activation. 相似文献
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The aim of this study was to investigate the effects of choline supplementation on intramuscular fat (IMF) and lipid oxidation in IUGR pigs. Twelve normal body weight (NBW) and twelve intrauterine growth retardation (IUGR) newborn piglets were collected and distributed into 4 treatments (Normal: N, Normal+Choline: N+C, IUGR: I, and IUGR+Choline: I+C) with 6 piglets in each treatment. At 23 d of age, NBW and IUGR pigs were fed basal or choline supplemented diets. The results showed that the IUGR pigs had significantly lower (P<0.05) BW as compared with the NBW pigs at 23 d, 73 d, and 120 d of age, however, there was a slight decreased (P>0.05) in BW of IUGR pigs than the NBW pigs at 200 d. Compared with the NBW pigs, pH of meat longissimus dorsi muscle was significantly lower (P<0.05), and the meat color was improved in IUGR pigs. The malondialdehyde (MDA) levels were significantly decreased (P<0.05), while triglyceride (TG) and IMF contents were significantly higher (P<0.05) in the IUGR pigs than the NBW pigs. IUGR up-regulated the mRNA gene expression of fatty acid synthetase (FAS) and acetyl-CoA carboxylase (ACC). Dietary choline significantly increased (P<0.05) the BW at 120d of age, however, significantly decreased (P<0.05) the TG and IMF contents in both IUGR and NBW pigs. FAS and sterol regulatory element-binding proteins 1 (SREBP1) mRNA gene expressions were increased (P<0.05) while the muscle-carnitine palmityl transferase (M-CPT) and peroxisome proliferators-activated receptorγ (PPARγ) mRNA (P<0.05) gene expressions were decreased in the muscles of the IUGR pigs by choline supplementation. Furthermore, choline supplementation significantly increased (P<0.05) the MDA content as well as the O2•¯ scavenging activity in meat of IUGR pigs. The results suggested that IUGR pigs showed a permanent stunting effect on the growth performance, increased fat deposition and oxidative stress in muscles. However, dietary supplementation of choline improved the fat deposition via enhancing the lipogenesis and reducing the lipolysis. 相似文献
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Charlemagne Alexander A. Lim Tahir Hussain Awan Pompe C. Sta. Cruz Bhagirath Singh Chauhan 《PloS one》2015,10(9)
Ischaemum rugosum Salisb. (Saramolla grass) is a noxious weed of rice that is difficult to control by chemical or mechanical means once established. A study was conducted to determine the effect of light, temperature, salt, drought, flooding, rice residue mulch, burial depth, and pre-emergence herbicides on seed germination and emergence of I. rugosum. Germination was stimulated by light and inhibited under complete darkness. Optimum temperature for germination was 30/20°C (97.5% germination). Germination reduced from 31 to 3.5% when the osmotic potential of the growing medium decreased from -0.1 to -0.6 MPa and no germination occurred at -0.8 MPa. Germination was 18 and 0.5% at 50 and 100 mM NaCl concentrations, respectively, but was completely inhibited at 150 mM or higher. Residue application at 1–6 t ha-1 reduced weed emergence by 35–88% and shoot biomass by 55–95%. The efficacy of pre-emergence herbicides increased with increasing application rates and decreased with increasing rice residue mulching. The efficacy of herbicides was in the order of oxadiazon> pendimethalin> pretilachlor. At 6 t ha-1, all herbicides, regardless of rates, did not differ from the control treatment. I. rugosum seeds buried at 2 cm or deeper did not emerge; however, they emerged by 4.5 and 0.5% at 0.5 and 1 cm depths, respectively, compared to the 39% germination for soil surface seeding. Flooding at 4 DAS or earlier reduced seedling emergence and shoot biomass while flooding at 8 DAS reduced only seedling emergence. The depth and timing of flooding independently reduced root biomass. Flooding at 4 and 6 cm depths reduced the root biomass. Relative to flooding on the day of sowing, flooding at 8 DAS increased root biomass by 89%. Similarly, flooding on the day of sowing and at 2 DAS reduced the root–shoot biomass ratio. Under the no-flood treatment, increasing rates of pretilachlor from 0.075 to 0.3 kg ai ha-1 reduced weed emergence by 61–79%. At the flooding depth of 2–4 cm, pretilachlor reduced weed emergence and shoot and root biomass, but the differences across rates were non-significant. Information generated in this study will be helpful in developing integrated weed management strategies for managing this weed. 相似文献
130.
Arshid Hussain Ganie Altaf Ahmad Renu Pandey Ibrahim M. Aref Peerzada Yasir Yousuf Sayeed Ahmad Muhammad Iqbal 《PloS one》2015,10(6)