title: Suppression of cAMP-dependent gene expression by cholecystokinin in the hippocampus.
abstract: Our previous study suggests that "the neuropeptidergic system" might promote a diversity of the mechanisms that regulate signal transmission in the hippocampus. Cholecystokinin (CCK) is the mostly expressed neuropeptide gene in the hippocampus. Here, we investigated whether CCK regulates immediate-early genes (Egr1/zif268 and Fos), critical indicators of cortical neuronal activity. We showed that CCK increased Egr1/zif268 promoter activity in a neuronal cell line, which is transfected with CCK(B) receptor. Unexpectedly, in living hippocampal slices, CCK significantly suppressed cAMP-induced expression of Egr1/zif268 and Fos through CCK(B) receptor activation. This suppression was involved in activating GABA(B) and cannabinoid 1 receptors. In addition to transient CCK modulation of action potentials on hippocampal principal neurons, we suggest that release of endogenous CCK might indirectly produce the suppression of cAMP-dependent gene expression in the hippocampus.
authors.affiliation: Okinawa Institute of Science and Technology, Okinawa 904-2234, Japan. nakamun@gmail.com
authors.forename: N H
authors.initials: NH
authors.lastname: Nakamura
authors.forename: K
authors.initials: K
authors.lastname: Akiyama
authors.forename: T
authors.initials: T
authors.lastname: Naito
mesh_terms: D000200:Action Potentials / Q000187:drug effects / Q000502:physiology; D000818:Animals; D015153:Blotting, Western; D002766:Cholecystokinin / Q000378:metabolism*; D000242:Cyclic AMP / Q000378:metabolism; D015870:Gene Expression; D005786:Gene Expression Regulation / Q000502:physiology*; D017781:Genes, Immediate-Early / Q000502:physiology*; D006624:Hippocampus / Q000378:metabolism*; D051379:Mice; D008810:Mice, Inbred C57BL; D009924:Organ Culture Techniques; D016716:PC12 Cells; D051381:Rats; D011949:Receptors, Cholecystokinin / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D009435:Synaptic Transmission / Q000502:physiology; D014162:Transfection
chemical_list: D011949:Receptors, Cholecystokinin; D002766:Cholecystokinin; D000242:Cyclic AMP