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41.
42.
Cycling populations of Aedes aegypti were set up in cages and managed in such a way that the populations had a maximum of threefold recovery potential in response to control measures. Into three such populations daily releases were made of males which had been chemosterilised, or were double translocation heterozygotes (T1T3) or T1T3 with sex ration distortion (DT1T3). Eradication of the populations was achieved with all cases, but the rate of suppression was markedly slower with T1T3 than the other two systems, with which the rates were similar. T1T3 and DT1T3 releases introduced considerable inherited genetic loads into the target populations. The results were in general agreement with computer predictions. 相似文献
43.
Prostaglandin E1 inhibits the pulmonary vascular pressor response to hypoxia and prostaglandin F2alpha. 总被引:1,自引:0,他引:1
In the anesthetised dog an infusion of exogenous prostaglandin E1 (100muG/min) inhibits the pulmonary vascular pressor response to hypoxia. Both 25 and 100muG/min PGE1 can reduce the transient pulmonary hypertension caused by a bolus of prostaglandin F2alpha. This suggests that hypoxia and PGF2alpha may share a final common pathway in producing pulmonary vasoconstriction. These results may help to explain the mechanism by which endotoxin inhibits the pulmonary vascular response to hypoxia. This effect is probably achieved by stimulating the production of an endogenous dilator prostaglandin. Exogenous PGE1 can mimic this effect. 相似文献
44.
45.
Endothelin is one of the most potent vasoconstrictors known. It plays an important role in the regulation of vascular tone and in the development of many cardiovascular diseases. This study focuses on the receptor types and the Ca2+ mobilization responsible for endothelin-1 (ET-1) contraction in de-endothelialized pig coronary artery rings. ET-1 contracted the artery rings with an EC50 = 6.5 ± 1 nM and a maximum contraction which was 98.6 ± 9% of the contraction produced by 60 mM KCl. BQ123 (5 µM), an ETA antagonist, reversed 78 ± 3% of the ET-1 contraction (50 nM). IRL1620, a selective ETB agonist, produced 23 ± 3% of the total ET-1 contraction with an EC50 = 12.7 ± 2 nM. More than 85% of the contraction due to 100 nM IRL 1620 was inhibited by 200 nMBQ788, an ETB antagonist. Therefore, approximately 80% of the ET-1 contraction in this artery occurred via ETA receptors, and the other 20% was mediated by ETB receptors. To assess the Ca2+ pools utilized during the ET-1 response, ET-1 contraction was also examined in medium containing an L-type Ca2+ channel blocker nitrendipine, and in Ca2+ free medium containing 0.2 mM EGTA. In Ca2+ containing medium the contraction elicited by ET-1 was 98.6 ± 9% of the KCl contraction, however, in the presence 10 µM nitrendipine the ET-1 induced contraction was 54 ± 7% of the KCl contraction, and in Ca2+-free medium it was 13 ± 2%. Similarly, the IRL 1620 contractions in Ca2+ containing medium, in the presence of nitrendipine and in Ca2+-free medium were 22.4 ± 3%, 12 ± 3% and 11 ± 2% of the KCl response respectively. Thus, both ETA and ETB contractions utilize extracellular Ca2+ pools via L-type Ca2+ channels and other undefined route(s), as well as intracellular Ca2+ pools. In the pig coronary artery smooth muscle, ET-1 contractions occur predominantly via ETA receptors, with ETB receptors using similar Ca2+ mobilization pathways, but the ETB receptors appear to use the intracellular Ca2+ stores to a greater extent. 相似文献
46.
Oxalate-stimulation of ATP-dependent Ca-uptake is diminished during smooth muscle subcellular fractionation 总被引:1,自引:0,他引:1
The ATP-dependent azide-insensitive Ca-uptake by the postnuclear supernatant from rat myometrium is stimulated more by 5 mM oxalate than by 25 mM phosphate. During subcellular fractionation, however, the percent recovery of the oxalate stimulated Ca-uptake diminishes more rapidly than that of the Ca-uptake without any added oxalate or phosphate. The percent recovery of the phosphate stimulated Ca-uptake also diminishes but not to as low levels as that of the oxalate stimulated Ca-uptake. The net result is higher stimulation of this uptake by 25 mM phosphate than by 5 mM oxalate in the various sucrose density gradient fractions. This discrepancy in percent recoveries presents a major concern about the use of oxalate or phosphate stimulated Ca-uptake as a marker for smooth muscle membranes. 相似文献
47.
Diffusing capacity of the lung in Caucasians native to 3,100 m 总被引:2,自引:0,他引:2
A C DeGraff R F Grover R L Johnson J W Hammond J M Miller 《Journal of applied physiology》1970,29(1):71-76
48.
The output of individual neurons is dependent on both synaptic and intrinsic membrane properties. While it is clear that the response of an individual neuron can be facilitated or inhibited based on the summation of its constituent synaptic inputs, it is not clear whether subthreshold activity, (e.g. synaptic “noise”- fluctuations that do not change the mean membrane potential) also serve a function in the control of neuronal output. Here we studied this by making whole-cell patch-clamp recordings from 29 mouse thalamocortical relay (TC) neurons. For each neuron we measured neuronal gain in response to either injection of current noise, or activation of the metabotropic glutamate receptor-mediated cortical feedback network (synaptic noise). As expected, injection of current noise via the recording pipette induces shifts in neuronal gain that are dependent on the amplitude of current noise, such that larger shifts in gain are observed in response to larger amplitude noise injections. Importantly we show that shifts in neuronal gain are also dependent on the intrinsic sensitivity of the neuron tested, such that the gain of intrinsically sensitive neurons is attenuated divisively in response to current noise, while the gain of insensitive neurons is facilitated multiplicatively by injection of current noise- effectively normalizing the output of the dLGN as a whole. In contrast, when the cortical feedback network was activated, only multiplicative gain changes were observed. These network activation-dependent changes were associated with reductions in the slow afterhyperpolarization (sAHP), and were mediated at least in part, by T-type calcium channels. Together, this suggests that TC neurons have the machinery necessary to compute multiple output solutions to a given set of stimuli depending on the current level of network stimulation. 相似文献
49.
Kapil Dev Nasir Akbar Mir Avishek Biswas Jyoti Kannoujia Jubeda Begum Rajiv Kant 《Letters in applied microbiology》2020,71(5):520-530
This study investigated the effects of dietary Bifidobacterium bifidum (BFD) and mannan-oligosaccharide (MOS), as a synbiotic, on the production performance, gut microbiology, serum biochemistry, antioxidant profile and health indices of broiler chicken. Six dietary treatments were T1 (negative control), T2 (positive control-20 mg antibiotic BMD kg−1 diet; BMD: bacitracin methylene disalicylate), T3 (0·1% MOS + 106 CFU BFD per g feed), T4 (0·1% MOS + 107 CFU BFD per g feed), T5 (0·2% MOS + 106 CFU BFD per g feed) and T6 (0·2% MOS + 107 CFU BFD per g feed). Significantly (P < 0·01) better growth performance and efficiency was observed in birds supplemented with 0·2% MOS along with 106 CFU BFD per g of feed compared to BMD and control birds. Supplementation with 0·2% MOS along with either 106 or 107 CFU BFD per g feed reduced (P < 0·01) the gut coliform, Escherichia coli, total plate count, and Clostridium perfringens count and increased the Lactobacillus and Bifidobacterium count. Significantly (P < 0·01) higher serum and liver antioxidant enzyme pool, serum HDL cholesterol and lower serum glucose, triglyceride, total cholesterol, cardiac risk ratio, atherogenic coefficient and atherogenic index of plasma were observed in birds supplemented with 0·2% MOS along with 106 CFU BFD per g of feed compared to control or BMD supplemented birds. Better production performance, gut microbial composition, serum biochemistry, antioxidant profile and health indices were depicted by broiler chicken supplemented with 0·2% MOS and 106 CFU BFD per g of feed. 相似文献
50.
Kumar Ritesh Khungar Lisha Shimphrui Rinchuila Tiwari Lalit Dev Tripathi Gayatri Sarkar Neelam K. Agarwal Surekha-Katiyar Agarwal Manu Grover Anil 《Journal of plant biochemistry and biotechnology.》2020,29(4):715-732
Journal of Plant Biochemistry and Biotechnology - Caseinolytic protease (Clp)/Hsp100 proteins are members of the AAA+ (ATPase associated with a variety of cellular activities) family of proteins... 相似文献