title: Presynaptic alpha-7 nicotinic acetylcholine receptors modulate excitatory synaptic transmission in hippocampal neurons.
abstract: The effects of presynaptic nicotinic acetylcholine receptors (nAChRs) on excitatory synaptic transmission in CA1 pyramidal neurons of the rat hippocampus were examined by blind whole-cell patch clamp recording from hippocampal slice preparations. Local application of the nAChRs agonist dimethylphenyl-piperazinium iodide (DMPP) did not induce a postsynaptic current response in CA1 pyramidal cells. However, DMPP enhanced the frequency and amplitude of spontaneous excitatory postsynaptic current (sEPSC) in these cells in a dose-dependent manner. This enhancement was blocked by the selective nicotinic alpha-7 receptor antagonist alpha-bungarotoxin, but not by the antagonist mecamylamine, hexamethonium or dihydro-beta-erythroidine. The frequency of miniature excitatory postsynaptic current (mEPSC) in CA1 pyramidal neurons was also increased by application of DMPP, indicating a presynaptic site of action of the agonist. Taken together, these results suggest that activation of presynaptic nAChRs in CA1 pyramidal neurons, which contain alpha-7 subunits, potentiates presynaptic glutamate release and consequently modulate excitatory synaptic transmission in the hippocampus.
authors.affiliation: Beijing Institute of Pharmacology and Toxicology, Beijing 100850. zhenwei_Liu@yahoo.com
authors.forename: Zhen-Wei
authors.initials: ZW
authors.lastname: Liu
authors.forename: Sheng
authors.initials: S
authors.lastname: Yang
authors.forename: Yong-Xiang
authors.initials: YX
authors.lastname: Zhang
authors.forename: Chuan-Hui
authors.initials: CH
authors.lastname: Liu
mesh_terms: D000818:Animals; D002038:Bungarotoxins / Q000502:physiology; D004246:Dimethylphenylpiperazinium Iodide / Q000494:pharmacology; D018698:Glutamic Acid / Q000494:pharmacology; D006624:Hippocampus / Q000502:physiology*; D008297:Male; D009474:Neurons / Q000502:physiology; D018722:Nicotinic Agonists / Q000494:pharmacology; D010138:Pacemaker, Artificial; D018408:Patch-Clamp Techniques; D051381:Rats; D017208:Rats, Wistar; D011978:Receptors, Nicotinic / Q000502:physiology*; D017661:Receptors, Presynaptic / Q000502:physiology*; D013569:Synapses / Q000502:physiology; D009435:Synaptic Transmission; D064569:alpha7 Nicotinic Acetylcholine Receptor
chemical_list: D002038:Bungarotoxins; C579165:Chrna7 protein, rat; D018722:Nicotinic Agonists; D011978:Receptors, Nicotinic; D017661:Receptors, Presynaptic; D064569:alpha7 Nicotinic Acetylcholine Receptor; D018698:Glutamic Acid; D004246:Dimethylphenylpiperazinium Iodide