Long-term potentiation （LTP） at synapses between primary afferents and spinal dorsal horn neurons induced by noxious electrical stimulation or injury of peripheral nerve is con- sidered to underlie chronic pain [1]....Long-term potentiation （LTP） at synapses between primary afferents and spinal dorsal horn neurons induced by noxious electrical stimulation or injury of peripheral nerve is con- sidered to underlie chronic pain [1]. The mechanisms of the spinal LTP have been intensively investigated, since it was discovered in 1995 [2]. In recent years, spinal application of ATP [3], brain-derived neurotrophic factor （BDNF） [4] and opioid [5] has been shown to induce spinal LTP at C-fiber synapses in the absence of conditioning activation of primary afferents. This is contrary to the general belief that coinci- dent pre- and postsynaptic activity is needed for LTP induction. Recently, Sandkiihler and his co-workers reported in Science that combined activation of microglia and astro- cytes by P2X7 receptor agonist BzATP induces LTP at synapses between afferent C-fibers and spinal lamina I neurons in the absence of presynaptic activation, which is termed gliogenic LTP [6] （Fig. 1C）. To determine the rela- tionship between the gliogenic LTP and high frequency stimulation （HFS）-indueed LTP, they used transverse lum- bar spinal cord slices with long dorsal roots which were separated into halves. Twenty two lamina I neurons that received independent monosynaptic C-fiber inputs from each dorsal root half were recorded. Homosynaptic LTP is recorded in 12 neurons, among them 6 neurons also show heterosynaptic LTP （Fig. 1A）. Interestingly, heterosynaptic LTP is also induced in 5 neurons in which HFS fails to induce homosynaptic LTP （Fig. 1B）.展开更多
The effects of RKM in comparison with pectin, algin and agar on lipid levels in serum and liver and on liver histopathology in rats were studied. In addition, the effects of all the tested materials on the composition...The effects of RKM in comparison with pectin, algin and agar on lipid levels in serum and liver and on liver histopathology in rats were studied. In addition, the effects of all the tested materials on the composition and output of fecal bile acid were observed. All four kinds of dietary fiber were given at a level of 5% of diet to young male rats of Wistar strain fed on a lipid-rich diet contalning 5 % lard, 1% cholesteral and 0. 25 % cholate. All the dietary fibers tested have similar effects on serum lipid composition. In all groups, these substances prevent ed increases in total cholesterol in fasting serum, but the level of triglyceride was tmchangd.The concentrations of totaI cholesterol and triglyceride in the liver were lower in the RKM group than in the control group and the other three groups. Hepatic histopathological exami nation also showed the most significant lipotropic effect in the RKM group. The daily output of fecal bile acids (CDCA+GDCA) was significantly increased in the four experimental groups than in the normal group and the control group. The increase of CDCA was more significant than GDCA, suggesting that the increase of fecal bile acids, especially CDCA, may be one of the mechanisms by which RKM and the other three dietary fibers exerts a hypocholesterolemic effect展开更多
LepA, the highly conserved translational GTPase (trGTPase), triggers one-codon back-movement of the elongating ribosome. Here we identify a new enzymatic activity
文摘Long-term potentiation （LTP） at synapses between primary afferents and spinal dorsal horn neurons induced by noxious electrical stimulation or injury of peripheral nerve is con- sidered to underlie chronic pain [1]. The mechanisms of the spinal LTP have been intensively investigated, since it was discovered in 1995 [2]. In recent years, spinal application of ATP [3], brain-derived neurotrophic factor （BDNF） [4] and opioid [5] has been shown to induce spinal LTP at C-fiber synapses in the absence of conditioning activation of primary afferents. This is contrary to the general belief that coinci- dent pre- and postsynaptic activity is needed for LTP induction. Recently, Sandkiihler and his co-workers reported in Science that combined activation of microglia and astro- cytes by P2X7 receptor agonist BzATP induces LTP at synapses between afferent C-fibers and spinal lamina I neurons in the absence of presynaptic activation, which is termed gliogenic LTP [6] （Fig. 1C）. To determine the rela- tionship between the gliogenic LTP and high frequency stimulation （HFS）-indueed LTP, they used transverse lum- bar spinal cord slices with long dorsal roots which were separated into halves. Twenty two lamina I neurons that received independent monosynaptic C-fiber inputs from each dorsal root half were recorded. Homosynaptic LTP is recorded in 12 neurons, among them 6 neurons also show heterosynaptic LTP （Fig. 1A）. Interestingly, heterosynaptic LTP is also induced in 5 neurons in which HFS fails to induce homosynaptic LTP （Fig. 1B）.
文摘The effects of RKM in comparison with pectin, algin and agar on lipid levels in serum and liver and on liver histopathology in rats were studied. In addition, the effects of all the tested materials on the composition and output of fecal bile acid were observed. All four kinds of dietary fiber were given at a level of 5% of diet to young male rats of Wistar strain fed on a lipid-rich diet contalning 5 % lard, 1% cholesteral and 0. 25 % cholate. All the dietary fibers tested have similar effects on serum lipid composition. In all groups, these substances prevent ed increases in total cholesterol in fasting serum, but the level of triglyceride was tmchangd.The concentrations of totaI cholesterol and triglyceride in the liver were lower in the RKM group than in the control group and the other three groups. Hepatic histopathological exami nation also showed the most significant lipotropic effect in the RKM group. The daily output of fecal bile acids (CDCA+GDCA) was significantly increased in the four experimental groups than in the normal group and the control group. The increase of CDCA was more significant than GDCA, suggesting that the increase of fecal bile acids, especially CDCA, may be one of the mechanisms by which RKM and the other three dietary fibers exerts a hypocholesterolemic effect
文摘LepA, the highly conserved translational GTPase (trGTPase), triggers one-codon back-movement of the elongating ribosome. Here we identify a new enzymatic activity
