title: ZD7288, a selective hyperpolarization-activated cyclic nucleotide-gated channel blocker, inhibits hippocampal synaptic plasticity.
abstract: 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 Ca(2+) concentration [Ca(2+)]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 [Ca(2+)]i in a concentration-dependent manner and reversed 8-Br-cAMP-mediated facilitation of these glutamate-induced [Ca(2+)]i rises. Our results suggest that ZD7288 inhibits hippocampal synaptic plasticity both glutamate release and resultant [Ca(2+)]i increases in rat hippocampal neurons.
authors.affiliation: Department of Laboratory Medicine, Affiliated Pu'ai Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei Province, China.
authors.forename: Xiao-Xue
authors.initials: XX
authors.lastname: Zhang
authors.affiliation: Department of Laboratory Medicine, Affiliated Pu'ai Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei Province, China.
authors.forename: Xiao-Chun
authors.initials: XC
authors.lastname: Min
authors.affiliation: Department of Pharmacology, School of Basic Medical Sciences, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei Province, China.
authors.forename: Xu-Lin
authors.initials: XL
authors.lastname: Xu
authors.affiliation: School of Biomedical Engineering, Hubei University of Science and Technology, Xianning, Hubei Province, China.
authors.forename: Min
authors.initials: M
authors.lastname: Zheng
authors.affiliation: Department of Pharmacology, School of Basic Medical Sciences, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei Province, China.
authors.forename: Lian-Jun
authors.identifier: 0000-0001-9708-6442
authors.initials: LJ
authors.lastname: Guo
keywords: Ih channels; ZD7288; field excitatory postsynaptic potentials; glutamate release; long-term potentiation; nerve regeneration; neural regeneration; perforant path–CA3 synapse