Aim: To study the effects of rhynchophylline (Rhy) on the L type calcium channels in freshly dissociated cortical neurons of Wistar rats during acute hypoxia. Methods: Cell attached configuration of patch clamp tech...Aim: To study the effects of rhynchophylline (Rhy) on the L type calcium channels in freshly dissociated cortical neurons of Wistar rats during acute hypoxia. Methods: Cell attached configuration of patch clamp technique. L type calcium channel was activated by stepping from 40 mV to 0 mV. Results: The results showed that the L type calcium channels of cortical neurons were activated by acute hypoxia. The mean open time of the channel was increased, the mean close time decreased and the open state probability raised during acute hypoxia. Rhy (15 and 30μmol·L -1 ) in concentration dependent manner blocked activity of the channels. The drug shortened the mean open time of the channels from 8 87 ms to 3 03 ms and 2 23 ms ( P 【0 001), prolonged the mean close time from 9 23 ms to 38 84 ms and 54 43 ms ( P 【0 001), and decreased the open state probability from 0 142 to 0 031 and 0 025 ( P 【0 001) under the hypoxia condition, respectively. The effects of Rhy were similar to but weaker than those of verapamil (15 μmol·L -1 ). Conclusion: The study confirmed that Rhy has the blockade effects on L type calcium channels in cortical neurons of rats during hypoxia, by which it protects the brain from hypoxic injury.展开更多
Horizontal cells (HCs) mediate negative feedback to photoreceptors. In the mammalian retina, there are two types of HCs, which are extensively coupled to neighboring cells through homologous gap junctions. The permeab...Horizontal cells (HCs) mediate negative feedback to photoreceptors. In the mammalian retina, there are two types of HCs, which are extensively coupled to neighboring cells through homologous gap junctions. The permeability and therefore the strength of feedback can be regulated by light intensity, dopamine and many other factors. However, the component(s) of the most prominent gap junctions, those between A-type HCs in the rabbit retina, is still unknown. In this study, we compared the sequences of many types of mammalian connexins, obtained partial sequences of rabbit connexin 50 and 57. Using specific primers designed against the rabbit sequences, we identified mRNAs of connexin 50 and/or 57 in visually selected single A-type HC using multiplex RT-PCR.展开更多
Objective: To observe the neuroprotective mechanism of water extract of Fomito^p^is Pinicola on MPP+ induced apoptosis of mesencephala dopaminergic cells in vitro. Methods: The antioxidant activity of fungi was determ...Objective: To observe the neuroprotective mechanism of water extract of Fomito^p^is Pinicola on MPP+ induced apoptosis of mesencephala dopaminergic cells in vitro. Methods: The antioxidant activity of fungi was determined by FRAP method. The anti-inflammatory activity of the fungi was detected by LPS-induced NO release method. Mesencephalic dopaminergic neurons were labeled by TH staining to observe the survival of THir neurons. Results: In the anti-oxidant activity assay, the Trolox equivalent anti-oxidant capacity (TEAC) of water extract of Fomitopsis Pinicola was determined to be ( 165.80±7.13 )μmol Trolox/g extract. Water extracts o f Fomitopsis Pinicola treatment(100, 5 0 ,2 5 , 12.5^g/ml) decreased NO formation significantly. MPP+ induced significant chromatin condensation in the nuclei of mesencephala dopaminergic neurons with nuclear lysis, the mitochondrial membrane potential decreased remarkably, and ROS production increased significantly. Compared with the MPP+ control group, the morphological changes of cell nuclei after apoptosis was reversed by water extract of Fomitopsis Pinicola. Water extract of Fomitopsis Pinicola treatment (50,25,12.5^g/ml) dramatically increased relative mitochondrial membrane potential compared with MPP+ control respectively. Compared with the MPP+ control, water extract of Fomitopsis Pinicola treatment (50, 25^g/ml) significantly decreased relative ROS formation respectively. Conclusions: Water extract of Fomitopsis Pinicola showed significant neuroprotective effect on mesencephala dopaminergic cells induced by MPP+. The water extract of Fomitopsis Pinicola showed antioxidant and anti-inflammatory activities. The mechanism of neuroprotective effect of water extract of Fomitopsis Pinicola may be related to inhibitory on mitochondrial oxidative stress.展开更多
Retinal degenerative diseases may induce the degeneration of outer retina and in turn,blindness.Nevertheless,due to the maintenance of inner retina,the coding and processing of visual neurons responses are still able ...Retinal degenerative diseases may induce the degeneration of outer retina and in turn,blindness.Nevertheless,due to the maintenance of inner retina,the coding and processing of visual neurons responses are still able to be executed naturally.Therefore,an effective retinal prosthesis device may be developed by mimicking the function of outer retina:transferring the visual light into artificial stimulus and delivering the stimulus to the retina aiming to evoke the neural responses.As two main developing directions for current retinal prosthesis,epiretinal(ER)and subretinal(SR)prosthesis are both undergoing experimental stage and possessing advantages and limitations.Further investigations in power supply,biocompatibility,etc.are still required.Additionally,suprachoroidal transretinal stimulation(STS)and neurotransmitter-induced stimulation as some other alternatives in retinal prosthesis are also considered as promising research directions,although they are not mature enough to be applied commercially,either.展开更多
Diabetic retinopathy （DR） is one of the most common retinal diseases world-wide. It has a complex pathology that involves the vasculature of the inner retina and breakdown of the blood-retinal barrier. Extensive res...Diabetic retinopathy （DR） is one of the most common retinal diseases world-wide. It has a complex pathology that involves the vasculature of the inner retina and breakdown of the blood-retinal barrier. Extensive research has determined that DR is not only a vascular disease but also has a neurodegenerative component and that essentially all types of ceils in the retina are affected, leading to chronic loss of visual function. A great deal of work using animal models of DR has established the loss of neurons and pathology of other cell types, including supporting glial cells. There has also been an increased emphasis on measuring retinal function in the models, as well as further validation and extension of the animal studies by clinical and translational research. This article will attempt to summarize the more recent developments in research towards understanding the complexities of retinal neurodegeneration and functional vision loss in DR.展开更多
文摘Aim: To study the effects of rhynchophylline (Rhy) on the L type calcium channels in freshly dissociated cortical neurons of Wistar rats during acute hypoxia. Methods: Cell attached configuration of patch clamp technique. L type calcium channel was activated by stepping from 40 mV to 0 mV. Results: The results showed that the L type calcium channels of cortical neurons were activated by acute hypoxia. The mean open time of the channel was increased, the mean close time decreased and the open state probability raised during acute hypoxia. Rhy (15 and 30μmol·L -1 ) in concentration dependent manner blocked activity of the channels. The drug shortened the mean open time of the channels from 8 87 ms to 3 03 ms and 2 23 ms ( P 【0 001), prolonged the mean close time from 9 23 ms to 38 84 ms and 54 43 ms ( P 【0 001), and decreased the open state probability from 0 142 to 0 031 and 0 025 ( P 【0 001) under the hypoxia condition, respectively. The effects of Rhy were similar to but weaker than those of verapamil (15 μmol·L -1 ). Conclusion: The study confirmed that Rhy has the blockade effects on L type calcium channels in cortical neurons of rats during hypoxia, by which it protects the brain from hypoxic injury.
基金supported by a MOST Major State Basic Research Program Grant to the Institute of Neuroscience(G2000077800)NSFC project grants(30170305,30270460)to SH
文摘Horizontal cells (HCs) mediate negative feedback to photoreceptors. In the mammalian retina, there are two types of HCs, which are extensively coupled to neighboring cells through homologous gap junctions. The permeability and therefore the strength of feedback can be regulated by light intensity, dopamine and many other factors. However, the component(s) of the most prominent gap junctions, those between A-type HCs in the rabbit retina, is still unknown. In this study, we compared the sequences of many types of mammalian connexins, obtained partial sequences of rabbit connexin 50 and 57. Using specific primers designed against the rabbit sequences, we identified mRNAs of connexin 50 and/or 57 in visually selected single A-type HC using multiplex RT-PCR.
文摘Objective: To observe the neuroprotective mechanism of water extract of Fomito^p^is Pinicola on MPP+ induced apoptosis of mesencephala dopaminergic cells in vitro. Methods: The antioxidant activity of fungi was determined by FRAP method. The anti-inflammatory activity of the fungi was detected by LPS-induced NO release method. Mesencephalic dopaminergic neurons were labeled by TH staining to observe the survival of THir neurons. Results: In the anti-oxidant activity assay, the Trolox equivalent anti-oxidant capacity (TEAC) of water extract of Fomitopsis Pinicola was determined to be ( 165.80±7.13 )μmol Trolox/g extract. Water extracts o f Fomitopsis Pinicola treatment(100, 5 0 ,2 5 , 12.5^g/ml) decreased NO formation significantly. MPP+ induced significant chromatin condensation in the nuclei of mesencephala dopaminergic neurons with nuclear lysis, the mitochondrial membrane potential decreased remarkably, and ROS production increased significantly. Compared with the MPP+ control group, the morphological changes of cell nuclei after apoptosis was reversed by water extract of Fomitopsis Pinicola. Water extract of Fomitopsis Pinicola treatment (50,25,12.5^g/ml) dramatically increased relative mitochondrial membrane potential compared with MPP+ control respectively. Compared with the MPP+ control, water extract of Fomitopsis Pinicola treatment (50, 25^g/ml) significantly decreased relative ROS formation respectively. Conclusions: Water extract of Fomitopsis Pinicola showed significant neuroprotective effect on mesencephala dopaminergic cells induced by MPP+. The water extract of Fomitopsis Pinicola showed antioxidant and anti-inflammatory activities. The mechanism of neuroprotective effect of water extract of Fomitopsis Pinicola may be related to inhibitory on mitochondrial oxidative stress.
文摘Retinal degenerative diseases may induce the degeneration of outer retina and in turn,blindness.Nevertheless,due to the maintenance of inner retina,the coding and processing of visual neurons responses are still able to be executed naturally.Therefore,an effective retinal prosthesis device may be developed by mimicking the function of outer retina:transferring the visual light into artificial stimulus and delivering the stimulus to the retina aiming to evoke the neural responses.As two main developing directions for current retinal prosthesis,epiretinal(ER)and subretinal(SR)prosthesis are both undergoing experimental stage and possessing advantages and limitations.Further investigations in power supply,biocompatibility,etc.are still required.Additionally,suprachoroidal transretinal stimulation(STS)and neurotransmitter-induced stimulation as some other alternatives in retinal prosthesis are also considered as promising research directions,although they are not mature enough to be applied commercially,either.
文摘Diabetic retinopathy （DR） is one of the most common retinal diseases world-wide. It has a complex pathology that involves the vasculature of the inner retina and breakdown of the blood-retinal barrier. Extensive research has determined that DR is not only a vascular disease but also has a neurodegenerative component and that essentially all types of ceils in the retina are affected, leading to chronic loss of visual function. A great deal of work using animal models of DR has established the loss of neurons and pathology of other cell types, including supporting glial cells. There has also been an increased emphasis on measuring retinal function in the models, as well as further validation and extension of the animal studies by clinical and translational research. This article will attempt to summarize the more recent developments in research towards understanding the complexities of retinal neurodegeneration and functional vision loss in DR.
