The selective hyperpolarization-activated cyclic nucleotide-gated（HCN） channel blocker 4-（N-ethyl-N-phenylamino）-1,2-dimethyl-6-（methylamino） pyrimidinium chloride（ZD7288） blocks the induction of long-term pot...The selective hyperpolarization-activated cyclic nucleotide-gated（HCN） channel blocker 4-（N-ethyl-N-phenylamino）-1,2-dimethyl-6-（methylamino） pyrimidinium chloride（ZD7288） blocks the induction of long-term potentiation in the perforant path-CA3 region in rat hippocampus in vivo. To explore the mechanisms underlying the action of ZD7288, we recorded excitatory postsynaptic potentials in perforant path-CA3 synapses in male Sprague-Dawley rats. We measured glutamate content in the hippocampus and in cultured hippocampal neurons using high performance liquid chromatography, and determined intracellular Ca2＋ concentration（[Ca2＋]i） using Fura-2. ZD7288 inhibited the induction and maintenance of long-term potentiation, and these effects were mirrored by the nonspecific HCN channel blocker cesium. ZD7288 also decreased glutamate release in hippocampal tissue and in cultured hippocampal neurons. Furthermore, ZD7288 attenuated glutamate-induced rises in [Ca2＋]i in a concentration-dependent manner and reversed 8-Br-c AMP-mediated facilitation of these glutamate-induced [Ca2＋]i rises. Our results suggest that ZD7288 inhibits hippocampal synaptic plasticity both glutamate release and resultant [Ca2＋]i increases in rat hippocampal neurons.展开更多
Many efforts have been made to understand excitotoxicity and develop neuroprotectants for the therapy of ischemic stroke.The narrow treatment time window is still to be solved.Given that the ischemic core expanded ove...Many efforts have been made to understand excitotoxicity and develop neuroprotectants for the therapy of ischemic stroke.The narrow treatment time window is still to be solved.Given that the ischemic core expanded over days,treatment with an extended time window is anticipated.Bestrophin1(BEST1)belongs to a bestrophin family of calcium-activated chloride channels.We revealed an increase in neuronal BEST1 expression and function within the peri-infarct from 8 to 48 h after ischemic stroke in mice.Interfering the protein expression or inhibiting the channel function of BEST1 by genetic manipulation displayed neuroprotective effects and improved motor functional deficits.Using electrophysiological recordings,we demonstrated that extrasynaptic glutamate release through BEST1 channel resulted in delayed excitotoxicity.Finally,we confirmed the therapeutic efficacy of pharmacological inhibition of BEST1 during 6—72 h post-ischemia in rodents.This delayed treatment prevented the expansion of infarct volume and the exacerbation of neurological functions.Our study identifies the glutamatereleasing BEST1 channel as a potential therapeutic target against ischemic stroke with a wide time window.展开更多
基金supported by grants from the National Natural Science Foundation of China,No.81173038,81001425
文摘The selective hyperpolarization-activated cyclic nucleotide-gated（HCN） channel blocker 4-（N-ethyl-N-phenylamino）-1,2-dimethyl-6-（methylamino） pyrimidinium chloride（ZD7288） blocks the induction of long-term potentiation in the perforant path-CA3 region in rat hippocampus in vivo. To explore the mechanisms underlying the action of ZD7288, we recorded excitatory postsynaptic potentials in perforant path-CA3 synapses in male Sprague-Dawley rats. We measured glutamate content in the hippocampus and in cultured hippocampal neurons using high performance liquid chromatography, and determined intracellular Ca2＋ concentration（[Ca2＋]i） using Fura-2. ZD7288 inhibited the induction and maintenance of long-term potentiation, and these effects were mirrored by the nonspecific HCN channel blocker cesium. ZD7288 also decreased glutamate release in hippocampal tissue and in cultured hippocampal neurons. Furthermore, ZD7288 attenuated glutamate-induced rises in [Ca2＋]i in a concentration-dependent manner and reversed 8-Br-c AMP-mediated facilitation of these glutamate-induced [Ca2＋]i rises. Our results suggest that ZD7288 inhibits hippocampal synaptic plasticity both glutamate release and resultant [Ca2＋]i increases in rat hippocampal neurons.
基金supported by STI2030-Major Project(2022ZD0211700,China)National Natural Science Foundation of China(82171293,82090042 and 82171368)Natural Science Foundation of Jiangsu Province(BK20211255,China)。
文摘Many efforts have been made to understand excitotoxicity and develop neuroprotectants for the therapy of ischemic stroke.The narrow treatment time window is still to be solved.Given that the ischemic core expanded over days,treatment with an extended time window is anticipated.Bestrophin1(BEST1)belongs to a bestrophin family of calcium-activated chloride channels.We revealed an increase in neuronal BEST1 expression and function within the peri-infarct from 8 to 48 h after ischemic stroke in mice.Interfering the protein expression or inhibiting the channel function of BEST1 by genetic manipulation displayed neuroprotective effects and improved motor functional deficits.Using electrophysiological recordings,we demonstrated that extrasynaptic glutamate release through BEST1 channel resulted in delayed excitotoxicity.Finally,we confirmed the therapeutic efficacy of pharmacological inhibition of BEST1 during 6—72 h post-ischemia in rodents.This delayed treatment prevented the expansion of infarct volume and the exacerbation of neurological functions.Our study identifies the glutamatereleasing BEST1 channel as a potential therapeutic target against ischemic stroke with a wide time window.
