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Ba R, Yang L, Zhang B, Jiang P, Ding Z, Zhou X, Yang Z, Zhao C. FOXG1 drives transcriptomic networks to specify principal neuron subtypes during the development of the medial pallium. SCIENCE ADVANCES 2023; 9:eade2441. [PMID: 36791184 PMCID: PMC9931217 DOI: 10.1126/sciadv.ade2441] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/03/2022] [Accepted: 01/19/2023] [Indexed: 06/18/2023]
Abstract
The medial pallium (MP) is the major forebrain region underlying learning and memory, spatial navigation, and emotion; however, the mechanisms underlying the specification of its principal neuron subtypes remain largely unexplored. Here, by postmitotic deletion of FOXG1 (a transcription factor linked to autism spectrum disorders and FOXG1 syndrome) and single-cell RNA sequencing of E17.5 MP in mice, we found that FOXG1 controls the specification of upper-layer retrosplenial cortical pyramidal neurons [RSC-PyNs (UL)], subiculum PyNs (SubC-PyNs), CA1-PyNs, CA3-PyNs, and dentate gyrus granule cells (DG-GCs) in the MP. We uncovered subtype-specific and subtype-shared FOXG1-regulated transcriptomic networks orchestrating MP neuron specification. We further demonstrated that FOXG1 transcriptionally represses Zbtb20, Prox1, and Epha4 to prevent CA3-PyN and DG-GC identities during the specification of RSC-PyNs (UL) and SubC-PyNs; FOXG1 directly activates Nr4a2 to promote SubC-PyN identity. We showed that TBR1, controlled by FOXG1 during CA1-PyN specification, was down-regulated. Thus, our study illuminates MP principal neuron subtype specification and related neuropathogenesis.
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Affiliation(s)
- Ru Ba
- Key Laboratory of Developmental Genes and Human Diseases, Ministry of Education, School of Medicine, Southeast University, Nanjing 210009, China
| | - Lin Yang
- State Key Laboratory of Medical Neurobiology, Institutes of Brain Science, MOE Frontier Research Center for Brain Science, Fudan University, Shanghai 200032, P.R. China
| | - Baoshen Zhang
- Key Laboratory of Developmental Genes and Human Diseases, Ministry of Education, School of Medicine, Southeast University, Nanjing 210009, China
| | - Pengfei Jiang
- Key Laboratory of Developmental Genes and Human Diseases, Ministry of Education, School of Medicine, Southeast University, Nanjing 210009, China
| | - Zhipeng Ding
- Key Laboratory of Developmental Genes and Human Diseases, Ministry of Education, School of Medicine, Southeast University, Nanjing 210009, China
| | - Xue Zhou
- Key Laboratory of Developmental Genes and Human Diseases, Ministry of Education, School of Medicine, Southeast University, Nanjing 210009, China
| | - Zhengang Yang
- State Key Laboratory of Medical Neurobiology, Institutes of Brain Science, MOE Frontier Research Center for Brain Science, Fudan University, Shanghai 200032, P.R. China
| | - Chunjie Zhao
- Key Laboratory of Developmental Genes and Human Diseases, Ministry of Education, School of Medicine, Southeast University, Nanjing 210009, China
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The potential role of the cholecystokinin system in declarative memory. Neurochem Int 2023; 162:105440. [PMID: 36375634 DOI: 10.1016/j.neuint.2022.105440] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2022] [Revised: 10/24/2022] [Accepted: 11/06/2022] [Indexed: 11/13/2022]
Abstract
As one of the most abundant neuropeptides in the central nervous system, cholecystokinin (CCK) has been suggested to be associated with higher brain functions, including learning and memory. In this review, we examined the potential role of the CCK system in declarative memory. First, we summarized behavioral studies that provide evidence for an important role of CCK in two forms of declarative memory-fear memory and spatial memory. Subsequently, we examined the electrophysiological studies that support the diverse roles of CCK-2 receptor activation in neocortical and hippocampal synaptic plasticity, and discussed the potential mechanisms that may be involved. Last but not least, we discussed whether the reported CCK-mediated synaptic plasticity can explain the strong influence of the CCK signaling system in neocortex and hippocampus dependent declarative memory. The available research supports the role of CCK-mediated synaptic plasticity in neocortex dependent declarative memory acquisition, but further study on the association between CCK-mediated synaptic plasticity and neocortex dependent declarative memory consolidation and retrieval is necessary. Although a direct link between CCK-mediated synaptic plasticity and hippocampus dependent declarative memory is missing, noticeable evidence from morphological, behavioral, and electrophysiological studies encourages further investigation regarding the potential role of CCK-dependent synaptic plasticity in hippocampus dependent declarative memory.
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Vera J, Lippmann K. Post-stroke epileptogenesis is associated with altered intrinsic properties of hippocampal pyramidal neurons leading to increased theta resonance. Neurobiol Dis 2021; 156:105425. [PMID: 34119635 DOI: 10.1016/j.nbd.2021.105425] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Revised: 06/01/2021] [Accepted: 06/08/2021] [Indexed: 01/23/2023] Open
Abstract
Brain insults like stroke, trauma or infections often lead to blood-brain barrier-dysfunction (BBBd) frequently resulting into epileptogenesis. Affected patients suffer from seizures and cognitive comorbidities that are potentially linked to altered network oscillations. It has been shown that a hippocampal BBBd in rats leads to in vivo seizures and increased power at theta (3-8 Hz), an important type of network oscillations. However, the underlying cellular mechanisms remain poorly understood. At membrane potentials close to the threshold for action potentials (APs) a subpopulation of CA1 pyramidal cells (PCs) displays intrinsic resonant properties due to an interplay of the muscarine-sensitive K+-current (IM) and the persistent Na+-current (INaP). Such resonant neurons are more excitable and generate more APs when stimulated at theta frequencies, being strong candidates for contributing to hippocampal theta oscillations during epileptogenesis. We tested this hypothesis by characterizing changes in intrinsic properties of hippocampal PCs one week after post-stroke epileptogenesis, a model associated with BBBd, using slice electrophysiology and computer modeling. We find a higher proportion of resonant neurons in BBBd compared to sham animals (47 vs. 29%), accompanied by an increase in their excitability. In contrast, BBBd non-resonant neurons showed a reduced excitability, presented with lower impedance and more positive AP threshold. We identify an increase in IM combined with either a reduction in INaP or an increase in ILeak as possible mechanisms underlying the observed changes. Our results support the hypothesis that a higher proportion of more excitable resonant neurons in the hippocampus contributes to increased theta oscillations and an increased likelihood of seizures in a model of post-stroke epileptogenesis.
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Affiliation(s)
- Jorge Vera
- Grass Laboratory, Marine Biological Laboratory, Woods Hole, MA 02543, USA; Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - Kristina Lippmann
- Grass Laboratory, Marine Biological Laboratory, Woods Hole, MA 02543, USA; Carl-Ludwig-Institute for Physiology, Medical Faculty, University of Leipzig, D-04103 Leipzig, Germany.
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Effects of Feeding-Related Peptides on Neuronal Oscillation in the Ventromedial Hypothalamus. J Clin Med 2019; 8:jcm8030292. [PMID: 30832213 PMCID: PMC6463148 DOI: 10.3390/jcm8030292] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2019] [Revised: 02/23/2019] [Accepted: 02/27/2019] [Indexed: 11/18/2022] Open
Abstract
The ventromedial hypothalamus (VMH) plays an important role in feeding behavior, obesity, and thermoregulation. The VMH contains glucose-sensing neurons, the firing of which depends on the level of extracellular glucose and which are involved in maintaining the blood glucose level via the sympathetic nervous system. The VMH also expresses various receptors of the peptides related to feeding. However, it is not well-understood whether the action of feeding-related peptides mediates the activity of glucose-sensing neurons in the VMH. In the present study, we examined the effects of feeding-related peptides on the burst-generating property of the VMH. Superfusion with insulin, pituitary adenylate cyclase-activating polypeptide, corticotropin-releasing factor, and orexin increased the frequency of the VMH oscillation. In contrast, superfusion with leptin, cholecystokinin, cocaine- and amphetamine-regulated transcript, galanin, ghrelin, and neuropeptide Y decreased the frequency of the oscillation. Our findings indicated that the frequency changes of VMH oscillation in response to the application of feeding-related peptides showed a tendency similar to changes of sympathetic nerve activity in response to the application of these substances to the brain.
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Wyeth MS, Zhang N, Houser CR. Increased cholecystokinin labeling in the hippocampus of a mouse model of epilepsy maps to spines and glutamatergic terminals. Neuroscience 2011; 202:371-83. [PMID: 22155653 DOI: 10.1016/j.neuroscience.2011.11.056] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2011] [Accepted: 11/24/2011] [Indexed: 12/01/2022]
Abstract
The neuropeptide cholecystokinin (CCK) is abundant in the CNS and is expressed in a subset of inhibitory interneurons, particularly in their axon terminals. The expression profile of CCK undergoes numerous changes in several models of temporal lobe epilepsy. Previous studies in the pilocarpine model of epilepsy have shown that CCK immunohistochemical labeling is substantially reduced in several regions of the hippocampal formation, consistent with decreased CCK expression as well as selective neuronal degeneration. However, in a mouse pilocarpine model of recurrent seizures, increases in CCK-labeling also occur and are especially striking in the hippocampal dendritic layers of strata oriens and radiatum. Characterizing these changes and determining the cellular basis of the increased labeling were the major goals of the current study. One possibility was that the enhanced CCK labeling could be associated with an increase in GABAergic terminals within these regions. However, in contrast to the marked increase in CCK-labeled structures, labeling of GABAergic axon terminals was decreased in the dendritic layers. Likewise, cannabinoid receptor 1-labeled axon terminals, many of which are CCK-containing GABAergic terminals, were also decreased. These findings suggested that the enhanced CCK labeling was not due to an increase in GABAergic axon terminals. The subcellular localization of CCK immunoreactivity was then examined using electron microscopy, and the identities of the structures that formed synaptic contacts were determined. In pilocarpine-treated mice, CCK was observed in dendritic spines and these were proportionally increased relative to controls, whereas the proportion of CCK-labeled terminals forming symmetric synapses was decreased. In addition, CCK-positive axon terminals forming asymmetric synapses were readily observed in these mice. Double labeling with vesicular glutamate transporter 1 and CCK revealed colocalization in numerous terminals forming asymmetric synapses, confirming the glutamatergic identity of these terminals. These data raise the possibility that expression of CCK is increased in hippocampal pyramidal cells in mice with recurrent, spontaneous seizures.
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Affiliation(s)
- M S Wyeth
- Department of Neurobiology, CHS 73-235, David Geffen School of Medicine at the University of California Los Angeles, 10833 Le Conte Avenue, Los Angeles, CA 90095-1763, USA
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Nakamura NH, Akiyama K, Naito T. Suppression of cAMP-dependent gene expression by cholecystokinin in the hippocampus. Neuroscience 2011; 187:15-23. [PMID: 21540082 DOI: 10.1016/j.neuroscience.2011.04.031] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2011] [Revised: 03/18/2011] [Accepted: 04/13/2011] [Indexed: 11/25/2022]
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.
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Affiliation(s)
- N H Nakamura
- Okinawa Institute of Science and Technology, Okinawa 904-2234, Japan.
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Cholecystokinin facilitates glutamate release by increasing the number of readily releasable vesicles and releasing probability. J Neurosci 2010; 30:5136-48. [PMID: 20392936 DOI: 10.1523/jneurosci.5711-09.2010] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Cholecystokinin (CCK), a neuropeptide originally discovered in the gastrointestinal tract, is abundantly distributed in the mammalian brains including the hippocampus. Whereas CCK has been shown to increase glutamate concentration in the perfusate of hippocampal slices and in purified rat hippocampal synaptosomes, the cellular and molecular mechanisms whereby CCK modulates glutamatergic function remain unexplored. Here, we examined the effects of CCK on glutamatergic transmission in the hippocampus using whole-cell recordings from hippocampal slices. Application of CCK increased AMPA receptor-mediated EPSCs at perforant path-dentate gyrus granule cell, CA3-CA3 and Schaffer collateral-CA1 synapses without effects at mossy fiber-CA3 synapses. CCK-induced increases in AMPA EPSCs were mediated by CCK-2 receptors and were not modulated developmentally and transcriptionally. CCK reduced the coefficient of variation and paired-pulse ratio of AMPA EPSCs suggesting that CCK facilitates presynaptic glutamate release. CCK increased the release probability and the number of readily releasable vesicles with no effects on the rate of recovery from vesicle depletion. CCK-mediated increases in glutamate release required the functions of phospholipase C, intracellular Ca(2+) release and protein kinase Cgamma. CCK released endogenously from hippocampal interneurons facilitated glutamatergic transmission. Our results provide a cellular and molecular mechanism to explain the roles of CCK in the brain.
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Cholecystokinin: Role in thermoregulation and other aspects of energetics. Clin Chim Acta 2010; 411:329-35. [DOI: 10.1016/j.cca.2009.12.016] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2009] [Revised: 12/15/2009] [Accepted: 12/18/2009] [Indexed: 11/17/2022]
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Chung L, Moore SD, Cox CL. Cholecystokinin action on layer 6b neurons in somatosensory cortex. Brain Res 2009; 1282:10-9. [PMID: 19497313 DOI: 10.1016/j.brainres.2009.05.061] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2009] [Revised: 05/09/2009] [Accepted: 05/11/2009] [Indexed: 11/30/2022]
Abstract
Layer 6b in neocortex is a distinct sublamina at the ventral portion of layer 6. Corticothalamic projections arise from 6b neurons, but few studies have examined the functional properties of these cells. In the present study we examined the actions of cholecystokinin (CCK) on layer 6b neocortical neurons using whole-cell patch clamp recording techniques. We found that the general CCK receptor agonist CCK8S (sulfated CCK octapeptide) strongly depolarized the neurons, and this action persisted in the presence of tetrodotoxin, suggesting a postsynaptic site of action. The excitatory actions of CCK8S were mimicked by the selective CCK(B) receptor agonist CCK4, and attenuated by the selective CCK(B) receptor antagonist L365260, indicating a role for CCK(B) receptors. Voltage-clamp recordings revealed that CCK8S produced a slow inward current associated with a decreased conductance with a reversal potential near the K(+) equilibrium potential. In addition, intracellular cesium also blocked the inward current, suggesting the involvement of a K(+) conductance, likely K(leak). Our data indicate that CCK, acting via CCK(B) receptors, produces a long-lasting excitation of layer 6b neocortical neurons, and this action may play a critical role in modulation of corticothalamic circuit activity.
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Affiliation(s)
- Leeyup Chung
- Neuroscience Program, Beckman Institute, University of Illinois, Urbana, IL 61801, USA
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Karson MA, Whittington KC, Alger BE. Cholecystokinin inhibits endocannabinoid-sensitive hippocampal IPSPs and stimulates others. Neuropharmacology 2008; 54:117-28. [PMID: 17689570 PMCID: PMC2242378 DOI: 10.1016/j.neuropharm.2007.06.023] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2007] [Revised: 05/23/2007] [Accepted: 06/14/2007] [Indexed: 01/07/2023]
Abstract
Cholecystokinin (CCK) is the most abundant neuropeptide in the central nervous system. In the hippocampal CA1 region, CCK is co-localized with GABA in a subset of interneurons that synapse on pyramidal cell somata and apical dendrites. CCK-containing interneurons also uniquely express a high level of the cannabinoid receptor, CB(1), and mediate the retrograde signaling process called DSI. Reported effects of CCK on inhibitory post-synaptic potentials (IPSPs) in hippocampus are inconsistent, and include both increases and decreases in activity. Hippocampal interneurons are very heterogeneous, and these results could be reconciled if CCK affected different interneurons in different ways. To test this prediction, we used sharp microelectrode recordings from pyramidal cells with ionotropic glutamate receptors blocked, and investigated the effects of CCK on pharmacologically distinct groups of IPSPs during long-term recordings. We find that CCK, acting via the CCK(2) receptor, increases some IPSPs and decreases others, and most significantly, that the affected IPSPs can be classified into two groups by their pharmacological properties. IPSPs that are increased by carbachol (CCh-sIPSPs), are depressed by CCK, omega-conotoxin GVIA, and endocannabinoids. IPSPs that are enhanced by CCK (CCK-sIPSPs) are blocked by omega-agatoxin IVA, and are unaffected by carbachol or endocannabinoids. Interestingly, a CCK(2) antagonist enhances CCh-sIPSPs, suggesting normally they may be partially suppressed by endogenous CCK. In summary, our data are compatible with the hypothesis that CCK has opposite actions on sIPSPs that originate from functionally distinct interneurons.
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Affiliation(s)
- Miranda A Karson
- Department of Physiology, Program in Neuroscience, University of Maryland School of Medicine, 655 W. Baltimore Street, Baltimore, MD 21201, USA
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Maekawa F, Nakamori T, Uchimura M, Fujiwara K, Yada T, Tsukahara S, Kanamatsu T, Tanaka K, Ohki-Hamazaki H. Activation of cholecystokinin neurons in the dorsal pallium of the telencephalon is indispensable for the acquisition of chick imprinting behavior. J Neurochem 2007; 102:1645-1657. [PMID: 17697050 DOI: 10.1111/j.1471-4159.2007.04733.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Chick imprinting behavior is a good model for the study of learning and memory. Imprinting object is recognized and processed in the visual wulst, and the memory is stored in the intermediate medial mesopallium in the dorsal pallium of the telencephalon. We identified chicken cholecystokinin (CCK)-expressing cells localized in these area. The number of CCK mRNA-positive cells increased in chicks underwent imprinting training, and these cells expressed nuclear Fos immunoreactivity at high frequency in these regions. Most of these CCK-positive cells were glutamatergic and negative for parvalbumin immunoreactivity. Semi-quantitative PCR analysis revealed that the CCK mRNA levels were significantly increased in the trained chicks compared with untrained chicks. In contrast, the increase in CCK- and c-Fos-double-positive cells associated with the training was not observed after closure of the critical period. These results indicate that CCK cells in the dorsal pallium are activated acutely by visual training that can elicit imprinting. In addition, the CCK receptor antagonist significantly suppressed the acquisition of memory. These results suggest that the activation of CCK cells in the visual wulst as well as in the intermediate medial mesopallium by visual stimuli is indispensable for the acquisition of visual imprinting.
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Affiliation(s)
- Fumihiko Maekawa
- Laboratory of Molecular Neuroscience, School of Biomedical Science and Medical Research Institute, Tokyo Medical and Dental University, Bunkyo-ku, Tokyo, JapanDepartment of Physiology, Division of Integrative Physiology, Jichi Medical University, Shimotsuke, Tochigi, JapanResearch Center for Environmental Risk, National Institute for Environmental Studies, Onogawa, Tsukuba, Ibaraki, JapanDepartment of Environmental Engineering for Symbiosis, Faculty of Engineering, Soka University, Hachioji, Tokyo, JapanRecognition and Formation, Precursory Research for Embryonic Science and Technology (PRESTO), Japan Science and Technology Agency (JST), Kawaguchi, Saitama, Japan
| | - Tomoharu Nakamori
- Laboratory of Molecular Neuroscience, School of Biomedical Science and Medical Research Institute, Tokyo Medical and Dental University, Bunkyo-ku, Tokyo, JapanDepartment of Physiology, Division of Integrative Physiology, Jichi Medical University, Shimotsuke, Tochigi, JapanResearch Center for Environmental Risk, National Institute for Environmental Studies, Onogawa, Tsukuba, Ibaraki, JapanDepartment of Environmental Engineering for Symbiosis, Faculty of Engineering, Soka University, Hachioji, Tokyo, JapanRecognition and Formation, Precursory Research for Embryonic Science and Technology (PRESTO), Japan Science and Technology Agency (JST), Kawaguchi, Saitama, Japan
| | - Motoaki Uchimura
- Laboratory of Molecular Neuroscience, School of Biomedical Science and Medical Research Institute, Tokyo Medical and Dental University, Bunkyo-ku, Tokyo, JapanDepartment of Physiology, Division of Integrative Physiology, Jichi Medical University, Shimotsuke, Tochigi, JapanResearch Center for Environmental Risk, National Institute for Environmental Studies, Onogawa, Tsukuba, Ibaraki, JapanDepartment of Environmental Engineering for Symbiosis, Faculty of Engineering, Soka University, Hachioji, Tokyo, JapanRecognition and Formation, Precursory Research for Embryonic Science and Technology (PRESTO), Japan Science and Technology Agency (JST), Kawaguchi, Saitama, Japan
| | - Ken Fujiwara
- Laboratory of Molecular Neuroscience, School of Biomedical Science and Medical Research Institute, Tokyo Medical and Dental University, Bunkyo-ku, Tokyo, JapanDepartment of Physiology, Division of Integrative Physiology, Jichi Medical University, Shimotsuke, Tochigi, JapanResearch Center for Environmental Risk, National Institute for Environmental Studies, Onogawa, Tsukuba, Ibaraki, JapanDepartment of Environmental Engineering for Symbiosis, Faculty of Engineering, Soka University, Hachioji, Tokyo, JapanRecognition and Formation, Precursory Research for Embryonic Science and Technology (PRESTO), Japan Science and Technology Agency (JST), Kawaguchi, Saitama, Japan
| | - Toshihiko Yada
- Laboratory of Molecular Neuroscience, School of Biomedical Science and Medical Research Institute, Tokyo Medical and Dental University, Bunkyo-ku, Tokyo, JapanDepartment of Physiology, Division of Integrative Physiology, Jichi Medical University, Shimotsuke, Tochigi, JapanResearch Center for Environmental Risk, National Institute for Environmental Studies, Onogawa, Tsukuba, Ibaraki, JapanDepartment of Environmental Engineering for Symbiosis, Faculty of Engineering, Soka University, Hachioji, Tokyo, JapanRecognition and Formation, Precursory Research for Embryonic Science and Technology (PRESTO), Japan Science and Technology Agency (JST), Kawaguchi, Saitama, Japan
| | - Shinji Tsukahara
- Laboratory of Molecular Neuroscience, School of Biomedical Science and Medical Research Institute, Tokyo Medical and Dental University, Bunkyo-ku, Tokyo, JapanDepartment of Physiology, Division of Integrative Physiology, Jichi Medical University, Shimotsuke, Tochigi, JapanResearch Center for Environmental Risk, National Institute for Environmental Studies, Onogawa, Tsukuba, Ibaraki, JapanDepartment of Environmental Engineering for Symbiosis, Faculty of Engineering, Soka University, Hachioji, Tokyo, JapanRecognition and Formation, Precursory Research for Embryonic Science and Technology (PRESTO), Japan Science and Technology Agency (JST), Kawaguchi, Saitama, Japan
| | - Tomoyuki Kanamatsu
- Laboratory of Molecular Neuroscience, School of Biomedical Science and Medical Research Institute, Tokyo Medical and Dental University, Bunkyo-ku, Tokyo, JapanDepartment of Physiology, Division of Integrative Physiology, Jichi Medical University, Shimotsuke, Tochigi, JapanResearch Center for Environmental Risk, National Institute for Environmental Studies, Onogawa, Tsukuba, Ibaraki, JapanDepartment of Environmental Engineering for Symbiosis, Faculty of Engineering, Soka University, Hachioji, Tokyo, JapanRecognition and Formation, Precursory Research for Embryonic Science and Technology (PRESTO), Japan Science and Technology Agency (JST), Kawaguchi, Saitama, Japan
| | - Kohichi Tanaka
- Laboratory of Molecular Neuroscience, School of Biomedical Science and Medical Research Institute, Tokyo Medical and Dental University, Bunkyo-ku, Tokyo, JapanDepartment of Physiology, Division of Integrative Physiology, Jichi Medical University, Shimotsuke, Tochigi, JapanResearch Center for Environmental Risk, National Institute for Environmental Studies, Onogawa, Tsukuba, Ibaraki, JapanDepartment of Environmental Engineering for Symbiosis, Faculty of Engineering, Soka University, Hachioji, Tokyo, JapanRecognition and Formation, Precursory Research for Embryonic Science and Technology (PRESTO), Japan Science and Technology Agency (JST), Kawaguchi, Saitama, Japan
| | - Hiroko Ohki-Hamazaki
- Laboratory of Molecular Neuroscience, School of Biomedical Science and Medical Research Institute, Tokyo Medical and Dental University, Bunkyo-ku, Tokyo, JapanDepartment of Physiology, Division of Integrative Physiology, Jichi Medical University, Shimotsuke, Tochigi, JapanResearch Center for Environmental Risk, National Institute for Environmental Studies, Onogawa, Tsukuba, Ibaraki, JapanDepartment of Environmental Engineering for Symbiosis, Faculty of Engineering, Soka University, Hachioji, Tokyo, JapanRecognition and Formation, Precursory Research for Embryonic Science and Technology (PRESTO), Japan Science and Technology Agency (JST), Kawaguchi, Saitama, Japan
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Meis S, Munsch T, Sosulina L, Pape HC. Postsynaptic mechanisms underlying responsiveness of amygdaloid neurons to cholecystokinin are mediated by a transient receptor potential-like current. Mol Cell Neurosci 2007; 35:356-67. [PMID: 17482476 DOI: 10.1016/j.mcn.2007.03.012] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2006] [Revised: 03/16/2007] [Accepted: 03/27/2007] [Indexed: 10/23/2022] Open
Abstract
Projection neurons of mouse basolateral amygdala responded to CCK with an inward current at a holding potential of -70 mV. This response was mediated by CCK2 receptors as indicated by agonist and antagonist effectiveness, and conveyed via G-proteins of the G(q/11) family as it was abolished in gene knockout mice. Maximal current amplitude was insensitive to extracellular potassium, cesium, and calcium ions, respectively, whereas amplitude and reversal potential critically depended upon extracellular sodium concentration. The current reversed near -20 mV consistent with activation of a mixed cationic channel reminiscent of transient receptor potential (TRP) channels. Extracellular application of the non-selective TRP channel blockers 2-APB, flufenamic acid, Gd3+, and ruthenium red, respectively, inhibited CCK induced inward currents. Single cell PCR confirmed the expression of TRPC1,4,5 and coexpression of TRPC1 with TRPC4 or TRPC5 in some cells. CCK responses were associated with depolarization leading to an increase in cell excitability.
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Affiliation(s)
- Susanne Meis
- Institut für Physiologie, Medizinische Fakultät, Otto-von-Guericke-Universität, Leipziger Str. 44, D-39120 Magdeburg, Germany.
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Yang YM, Chung JM, Rhim H. Cholecystokinin-8S-Induced Intracellular Calcium Signaling in Acutely Isolated Periaqueductal Gray Neurons of the Rat. Biol Pharm Bull 2007; 30:297-302. [PMID: 17268069 DOI: 10.1248/bpb.30.297] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Many behavior studies indicate that cholecystokinin (CCK) is related to nociception and anxiety/panic actions in the midbrain periaqueductal gray (PAG). We previously reported that a sulfated form of CCK octapeptide (CCK-8S) produced excitatory effects at both pre- and postsynaptic loci in PAG neurons using slice preparations and whole-cell patch-clamp recordings. Here, we further examined the detailed mechanism of CCK-8S in acutely isolated PAG neurons of the rat using fura-2-based imaging of intracellular Ca2+ concentration ([Ca2+]i) and whole-cell patch-clamp recordings. Application of 1 microM CCK-8S produced an increase of [Ca2+]i, and its effect did not desensitize. This CCK-8S-induced [Ca2+]i increase was inhibited by the CCK2 receptor antagonist L-365260 but not by the CCK1 receptor antagonist L-364718. In addition, the effect of CCK-8S was eliminated by removing extracellular Ca2+, but not by an addition of the intracellular Ca2+ reuptake inhibitor thapsigargin. When simultaneous recordings of [Ca2+]i imaging and whole-cell patch-clamp were performed, CCK-8S-induced [Ca2+]i increase was significantly reduced at a membrane holding potential of -60 mV while CCK-8S-induced inward current was still observed. Current-voltage plots revealed that CCK-8S-induced inward current reversed near the equilibrium potential for K+ ions with a decreased membrane conductance. However, CCK-8S produced a significant inhibition on high-voltage-activated Ca2+ channel currents. These results suggest that CCK-8S can excite PAG neurons by inhibiting K+ channels, and CCK-8S-induced [Ca2+]i increase occurs secondary to depolarization. The evidence presented here expands our understanding of cellular mechanisms for CCK-mediated anti-analgesic and anxiogenic actions in the PAG.
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Affiliation(s)
- Yu-Mi Yang
- Biomedical Research Center, Korea Institute of Science and Technology (KIST), Seoul, Korea
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Yang YM, Chung JM, Rhim H. Cellular action of cholecystokinin-8S-mediated excitatory effects in the rat periaqueductal gray. Life Sci 2006; 79:1702-11. [PMID: 16797032 DOI: 10.1016/j.lfs.2006.05.027] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2006] [Revised: 05/18/2006] [Accepted: 05/31/2006] [Indexed: 11/25/2022]
Abstract
The peptide cholecystokinin (CCK) is one of the major neurotransmitters modulating satiety, nociception, and anxiety behavior. Although many behavioral studies showing anti-analgesic and anxiogenic actions of CCK have been reported, less is known about its cellular action in the central nervous system (CNS). Therefore, we examined the action of CCK in rat dorsolateral periaqueductal gray (PAG) neurons using slice preparations and whole-cell patch-clamp recordings. Application of CCK-8S produced an inward current accompanied by increased spontaneous synaptic activities. The CCK-8S-induced inward current (I(CCK)) was recovered after washout and reproduced by multiple exposures. Current-voltage plots revealed that I(CCK) reversed near the equilibrium potential for K(+) ions with a decreased membrane conductance. When several K(+) channel blockers were used, application of CdCl(2), TEA, or apamin significantly reduced I(CCK). I(CCK) was also significantly reduced by the CCK(2) receptor antagonist, L-365,260, while it was not affected by the CCK(1) receptor antagonist, L-364,718. Furthermore, we examined the effects of CCK-8S on miniature excitatory postsynaptic currents (mEPSCs) in order to determine the mechanism of CCK-mediated increase on synaptic activities. We found that CCK-8S increased the frequency of mEPSCs, but had no effect on mEPSC amplitude. This presynaptic effect persisted in the presence of CdCl(2) or Ca(2+)-free bath solution, but was completely abolished by pre-treatment with BAPTA-AM, thapsigargin or L-365,260. Taken together, our results indicate that CCK can excite PAG neurons at both pre- and postsynaptic loci via the activation of CCK(2) receptors. These effects may be important for the effects of CCK on behavior and autonomic function that are mediated via PAG neurons.
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Affiliation(s)
- Yu-Mi Yang
- Biomedical Research Center, Korea Institute of Science and Technology (KIST), 39-1 Hawholgok-dong Sungbuk-gu, Seoul 136-791, Korea
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Deng PY, Lei S. Bidirectional modulation of GABAergic transmission by cholecystokinin in hippocampal dentate gyrus granule cells of juvenile rats. J Physiol 2006; 572:425-42. [PMID: 16455686 PMCID: PMC1779673 DOI: 10.1113/jphysiol.2005.104463] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Cholecystokinin (CCK) interacts with two types of G protein-coupled receptors in the brain: CCK-A and CCK-B receptors. Both CCK and CCK-B receptors are widely distributed in the hippocampal formation, but the functions of CCK there have been poorly understood. In the present study, we initially examined the effects of CCK on GABA(A) receptor-mediated synaptic transmission in the hippocampal formation and then explored the underlying cellular mechanisms by focusing on the dentate gyrus region, where the highest levels of CCK-binding sites have been detected. Our results indicate that activation of CCK-B receptors initially and transiently increased spontaneous IPSC (sIPSC) frequency, followed by a persistent reduction. The effects of CCK were more evident in juvenile rats, suggesting that they are developmentally regulated. Cholecystokinin failed to modulate the miniature IPSCs recorded in the presence of TTX and the amplitude of the evoked IPSCs, but produced a transient increase followed by a reduction in action potential firing frequency recorded from GABAergic interneurons, suggesting that CCK acts by modulating the excitability of the interneurons to regulate GABA release. Cholecystokinin reduced the amplitude of the after-hyperpolarization of the action potentials, and application of paxilline or charybdotoxin considerably reduced CCK-mediated modulation of sIPSC frequency, suggesting that the effects of CCK are related to the inhibition of Ca(2+)-activated K(+) currents (I(K(Ca))). The effects of CCK were independent of the functions of phospholipase C, intracellular Ca(2+) release, protein kinase C or phospholipase A(2), suggesting a direct coupling between the G proteins of CCK-B receptors and I(K(Ca)). Our results provide a novel mechanism underlying CCK-mediated modulation of GABA release.
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Affiliation(s)
- Pan-Yue Deng
- Department of Pharmacology, Physiology and Therapeutics, School of Medicine and Health Sciences, University of North Dakota, Grand Forks, 58203, USA
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Gallopin T, Geoffroy H, Rossier J, Lambolez B. Cortical sources of CRF, NKB, and CCK and their effects on pyramidal cells in the neocortex. ACTA ACUST UNITED AC 2005; 16:1440-52. [PMID: 16339088 DOI: 10.1093/cercor/bhj081] [Citation(s) in RCA: 72] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
In order to investigate how neuropeptide transmission can modulate the neocortical network, we mapped the expression of neurokinin (NK) B, cholecystokinin (CCK), and corticotropin-releasing factor (CRF) and their receptors to neuronal types using patch-clamp and single-cell reverse transcription-polymerase chain reaction in acute slices of rat neocortex. Classification of neurons by unsupervised clustering based on the analysis of multiple electrophysiological and molecular properties disclosed 3 GABAergic interneuron clusters and 1 pyramidal cell cluster. The 3 neuropeptides were expressed in a cluster of interneurons characteristically expressing vasoactive intestinal peptide. CRF was additionally found in a cluster containing almost exclusively somatostatin-expressing interneurons, whereas CCK was present in all clusters. The respective receptors of these peptides, NK-3, CCK-B, and CRF-1, were essentially expressed in pyramidal cells. At -60 mV, pyramidal cells were weakly depolarized by each of these peptides. When pyramidal neurons were maintained to about 5 mV below spike threshold, depolarization induced by each peptide resulted in a long-lasting action potential discharge. Neuropeptide effects were prevented by selective antagonists of NK-3, CCK-B, and CRF-1 receptors. These results suggest that pyramidal neurons are the primary target of NKB, CCK, and CRF in the neocortex. They further indicate that specific interneuron types coordinate the release of these peptides and can induce a long-lasting increase of the excitability of the neocortical network.
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Affiliation(s)
- Thierry Gallopin
- Laboratoire de Neurobiologie et Diversité Cellulaire, Centre National de la Recherche Scientifique, Unité Mixte de Recherche 7637, Ecole Supérieure de Physique et de Chimie Industrielles, 10 rue Vauquelin, 75005 Paris, France
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Peters JH, Ritter RC, Simasko SM. Leptin and CCK modulate complementary background conductances to depolarize cultured nodose neurons. Am J Physiol Cell Physiol 2005; 290:C427-32. [PMID: 16192299 DOI: 10.1152/ajpcell.00439.2005] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
We have previously reported that intraceliac infusion of leptin induces a reduction of meal size that depends on intact vagal afferents. This effect of leptin is enhanced in the presence of cholecystokinin (CCK). The mechanisms by which leptin and CCK activate vagal afferent neurons are not known. In the present study, we have begun to address this question by using patch-clamp electrophysiological techniques to examine the mechanisms by which leptin and CCK activate cultured vagal afferents from adult rat nodose ganglia. We found that leptin depolarized 41 (60%) of 68 neurons. The magnitude of membrane depolarization was dependent on leptin concentration and occurred in both capsaicin-sensitive and capsaicin-insensitive neurons. We also found that a majority (16 of 22; 73%) of nodose neurons activated by leptin were also sensitive to CCK. CCK-induced depolarization was primarily associated with the increase of an inward current (11 of 12), whereas leptin induced multiple changes in background conductances through a decrease in an outward current (7 of 13), an increase in an inward current (3 of 13), or both (3 of 13). However, further isolation of background currents by recording in solutions that contained only sodium or only potassium revealed that both leptin and CCK were capable of increasing a sodium-dependent conductance or inhibiting a potassium-dependent conductance. Our results support the hypothesis that vagal afferents are a point of convergence and integration of leptin and CCK signaling for control of food intake and suggest multiple ionic mechanisms by which leptin and CCK activate vagal afferent neurons.
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Affiliation(s)
- J H Peters
- Program in Neuroscience, Department of Veterinary and Comparative Anatomy, Pharmacology, and Physiology, College of Veterinary Medicine, Washington State University, Pullman 99164-6520, USA.
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Szelényi Z, Hummel Z, Székely M, Pétervári E. CCK-8 and PGE1: central effects on circadian body temperature and activity rhythms in rats. Physiol Behav 2004; 81:615-21. [PMID: 15178154 DOI: 10.1016/j.physbeh.2004.02.025] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2003] [Revised: 02/05/2004] [Accepted: 02/18/2004] [Indexed: 11/20/2022]
Abstract
Cholecystokinin-octapeptide (CCK-8) has been shown to possess an acute thermogenic and hyperthermic action when given intracerebroventricularly in slightly restrained rats. To substantiate the febrile nature of that hyperthermia freely moving animals should be used and together with body core temperature, at least one behavioral parameter, such as general activity, should also be recorded. In the present studies, Wistar rats (N=34) exposed to thermoneutral (26-28 degrees C) or cold (4 degrees C) ambient temperature and to a 12:12-h light/darkness schedule were infused intracerebroventricularly with CCK-8 or prostaglandin E1 (PGE1) for several days using ALZET minipump and changes in body core temperature and general activity were recorded by biotelemetry (Minimitter). In rats exposed to a thermoneutral ambient temperature, low doses of CCK-8 induced slight but significant rises of day minima of circadian body temperature rhythm (CBTR) and with a high dose (1 microg/h) of the peptide--infused either at thermoneutrality or during cold exposure--an increase of acrometron could also be recorded. All of these changes were observed only during the first 2-4 days of 7-day-long infusions. Intracerebroventricular infusion of PGE1 administered at thermoneutrality in a dose of 1 microg/h for 7 days induced a marked rise in body core temperature with a disappearance of CBTR in some rats for 2-3 days or with rises of day minima/acrometron in others. General activity--running parallel with CBTR in periods without infusions--tended to be decreased when core temperature rose during the first couple of days of intracerebroventricular infusion of higher doses of CCK-8 or of PGE1. The decreased general activity--one component of sickness behavior--together with an increased body core temperature found in the present study, supports the view that they are components of a genuine fever induced by the central effect of the two mediators used.
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Affiliation(s)
- Zoltán Szelényi
- Department of Pathophysiology, Faculty of Medicine, University of Pécs, H-7602 Pécs, POB 99, Hungary.
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Jinno S, Kosaka T. Heterogeneous expression of the cholecystokinin-like immunoreactivity in the mouse hippocampus, with special reference to the dorsoventral difference. Neuroscience 2004; 122:869-84. [PMID: 14643757 DOI: 10.1016/j.neuroscience.2003.08.039] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The neuropeptide cholecystokinin (CCK) is widely distributed in the CNS. We herein investigated the immunocytochemical localization of CCK in the glutamatergic excitatory pathways in the mouse hippocampus, with particular reference to the dorsoventral difference. The intense CCK-like immunoreactivity (CCK-LI) was found in the mossy fiber pathway (stratum lucidum and dentate hilus) and in the inner molecular layer of the dentate gyrus. In the mossy fiber pathway, the CCK-LI was more intense at the ventral level than at the dorsal level. On the other hand, the CCK-LI in the stratum lucidum was more intense in the distal portion than in the proximal portion, both at the dorsal and ventral levels. High-resolution three-dimensional image analysis revealed the coexpression of CCK and synaptoporin (SPO) in the single mossy terminal, where they were spatially segregated but adjacent to each other. Quantitative image analysis indicated the difference in the amount of CCK within the mossy terminals along the dorsoventral and transverse axes of the hippocampus. On the other hand, in the inner molecular layer, CCK- and SPO-positive elements appeared to have little relation to each other. We also examined the postnatal development of the CCK-LI in the mouse hippocampus. The CCK-LI was detected in the inner molecular layer of the ventral dentate gyrus at postnatal day (P) 7. In the mossy fiber pathway, the CCK-LI was first evident at P 14, but it was restricted to the distal portion of the stratum lucidum in the ventral hippocampus. Interestingly, the distributions of the SPO immunoreactivity at P 7 were already similar to those of adult mice. The patterns of expression of CCK-LI at P 28 were almost similar to those of adult mice. The present data demonstrate the heterogeneous expression of CCK-LI in the mouse hippocampus, and provide a baseline to understand the role of CCK in the mouse brain.
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Affiliation(s)
- S Jinno
- Department of Anatomy and Neurobiology, Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan.
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Simasko SM, Ritter RC. Cholecystokinin activates both A- and C-type vagal afferent neurons. Am J Physiol Gastrointest Liver Physiol 2003; 285:G1204-13. [PMID: 12946940 DOI: 10.1152/ajpgi.00132.2003] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Patch-clamp electrophysiological methods were used on dissociated rat nodose neurons maintained in culture to determine whether responses to cholecystokinin (CCK) were associated with capsaicin-resistant (A type) or capsaicin-sensitive (C type) neurons. Nodose neurons were classified as A or C type on the basis of the characteristics of the Na+ current, a hyperpolarization-activated current, and sensitivity to a low concentration of capsaicin to ascertain the presence of vanilloid receptor 1 that has been associated with C-type neurons in sensory ganglia. It was expected that only capsaicin-sensitive C-type neurons would respond to CCK, because most vagally mediated actions of CCK are blocked by capsaicin treatment. However, we found that subpopulations of both A- and C-type neurons responded to CCK (24 and 38%, respectively). Thus some vagally mediated actions of CCK may be mediated by capsaicin insensitive A-type neurons.
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Affiliation(s)
- Steven M Simasko
- Program in Neuroscience, Department of Veterinary and Comparative Anatomy, Pharmacology and Physiology, College of Veterinary Medicine, Washington State University, Pullman, Washington 99164-6520, USA.
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21
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Cope DW, Maccaferri G, Márton LF, Roberts JDB, Cobden PM, Somogyi P. Cholecystokinin-immunopositive basket and Schaffer collateral-associated interneurones target different domains of pyramidal cells in the CA1 area of the rat hippocampus. Neuroscience 2002; 109:63-80. [PMID: 11784700 DOI: 10.1016/s0306-4522(01)00440-7] [Citation(s) in RCA: 113] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Two types of GABAergic interneurone are known to express cholecystokinin-related peptides in the isocortex: basket cells, which preferentially innervate the somata and proximal dendrites of pyramidal cells; and double bouquet cells, which innervate distal dendrites and dendritic spines. In the hippocampus, cholecystokinin immunoreactivity has only been reported in basket cells. However, at least eight distinct GABAergic interneurone types terminate in the dendritic domain of CA1 pyramidal cells, some of them with as yet undetermined neurochemical characteristics. In order to establish whether more than one population of cholecystokinin-expressing interneurone exist in the hippocampus, we have performed whole-cell current clamp recordings from interneurones located in the stratum radiatum of the hippocampal CA1 region of developing rats. Recorded neurones were filled with biocytin to reveal their axonal targets, and were tested for the presence of pro-cholecystokinin immunoreactivity. The results show that two populations of cholecystokinin-immunoreactive interneurones exist in the CA1 area (n=15 positive cells). Cholecystokinin-positive basket cells (53%) preferentially innervate stratum pyramidale and adjacent strata oriens and radiatum. A second population of cholecystokinin-positive cells, previously described as Schaffer collateral-associated interneurones [Vida et al. (1998) J. Physiol. 506, 755-773], have axons that ramify almost exclusively in strata radiatum and oriens, overlapping with the Schaffer collateral/commissural pathway originating from CA3 pyramidal cells. Two of seven of the Schaffer collateral-associated cells were also immunopositive for calbindin. Soma position and orientation in stratum radiatum, the number and orientation of dendrites, and the passive and active membrane properties of the two cell populations are only slightly different. In addition, in stratum radiatum and its border with lacunosum of perfusion-fixed hippocampi, 31.6+/-3.8% (adult) or 26.8+/-2.9% (postnatal day 17-20) of cholecystokinin-positive cells were also immunoreactive for calbindin. Therefore, at least two populations of pro-cholecystokinin-immunopositive interneurones, basket and Schaffer collateral-associated cells, exist in the CA1 area of the hippocampus, and are probably homologous to cholecystokinin-immunopositive basket and double bouquet cells in the isocortex. It is not known if the GABAergic terminals of double bouquet cells are co-aligned with specific glutamatergic inputs. However, in the hippocampal CA1 area, it is clear that the terminals of Schaffer collateral-associated cells are co-stratified with the glutamatergic input from the CA3 area, with as yet unknown functional consequences. The division of the postsynaptic neuronal surface by two classes of GABAergic cell expressing cholecystokinin in both the hippocampus and isocortex provides further evidence for the uniform synaptic organisation of the cerebral cortex.
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Affiliation(s)
- D W Cope
- MRC Anatomical Neuropharmacology Unit, Department of Pharmacology, Oxford University, Mansfield Road, Oxford OX1 3TH, UK.
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22
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Wilms K, Vierig G, Davidowa H. Interactive effects of cholecystokinin-8S and various serotonin receptor agonists on the firing activity of neostriatal neuronesin rats. Neuropeptides 2001; 35:257-70. [PMID: 12030810 DOI: 10.1054/npep.2001.0875] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
In rats anaesthetized with urethane single unit activity was extracellularly recorded in the neostriatum, and several drugs were microiontophoretically ejected. Separate administration of the sulfated octapeptide cholecystokinin (CCK-8S), serotonin (5-HT) or 8-OH-DPAT (a 5-HT(1A/7) receptor agonist) predominantly induced increases in the neuronal discharge rates (Wilcoxon test significant P<0.05), whereas the 5-HT(2A/2C) receptor agonist DOI affected only a few neurones and mainly reduced firing. After coadministration of CCK-8S and serotonin, activating effects also predominated (Wt P<0.05), but the neuronal responsiveness was significantly reduced (Chi2P<0.01). Similarly, concomitant application of CCK-8S and 8-OH-DPAT led to significant activation accompanied with a reduction of inhibitory effects. The block of serotonin- or 8-OH-DPAT-effects through specific 5-HT(1A) receptor antagonists implies the involvement of this receptor subtype within the striatum. In conclusion, concomitant action of CCK-8S and serotonin induces a mean level of neuronal activation that might promote normal function.
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Affiliation(s)
- K Wilms
- Johannes-Mueller-Institute of Physiology, Charité, Humboldt University, Berlin, Germany
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Abstract
The high abundance of the cholecystokinin octapeptide in various brain regions is expressed by involvement of this neuropeptide in diverse brain functions. This peptide is mostly, if not always, co-localized with classic transmitters in central nerve terminals. Since the functions of the coexisting transmitters are often different, differential regulation of their release is obvious. This differentiation is realized by differences in presynaptic localization, release dynamics, and calcium regulation. In addition, CCK release is locally modulated by receptors, kinases and phosphatases. The regulatory mechanisms of CCK release are placed into physiological perspective.
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Affiliation(s)
- W E Ghijsen
- Graduate School for the Neurosciences, Swammerdam Institute for Life Sciences, Section Neurobiology, University of Amsterdam, Kruislaan 320, 1090 GB Amsterdam, The Netherlands.
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Phelan KD, Newton BW. Intracellular recording of lamina X neurons in a horizontal slice preparation of rat lumbar spinal cord. J Neurosci Methods 2000; 100:145-50. [PMID: 11040377 DOI: 10.1016/s0165-0270(00)00247-8] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
A horizontal slice preparation of postnatal rat lumbar spinal cord has been developed which allows correlative observations of the morphology, electrophysiology, and receptor pharmacology of lamina X neurons. These slices better maintain afferent input and somatodendritic morphology and are amenable to subsequent immunohistochemical processing. Stable intracellular recordings obtained from postnatal day 14-45 animals reveal that a number of different intrinsic membrane conductances contribute to the regulation of excitability in lamina X neurons. In addition, lamina X neurons possess inhibitory GABAergic as well as excitatory glutamate and cholecystokinin receptors. This preparation will be useful in future studies designed to characterize developmental changes in the intrinsic membrane properties, synaptic profiles and neuropeptide responsiveness of lamina X neurons in the rat. Such a characterization is important given that lamina X represents a unique sexually dimorphic region that is a convergence site for somatic and visceral afferent inputs, which includes nociceptive information.
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Affiliation(s)
- K D Phelan
- Department of Anatomy/Slot 510 and Arkansas Center for Neuroscience, University of Arkansas for Medical Sciences, 4301 West Markham St., Little Rock, AR 72205-7199, USA.
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Abstract
The clinical efficacy of the ketogenic diet (KD) has now been well-documented. However, the underlying bases of KD antiepileptic efficacy are still a matter of speculation. A number of suggestions regarding underlying mechanisms have been offered, but all require rigorous testing. Development of appropriate animal model systems, and clear statement of experimentally testable hypotheses, are needed. Among the general hypotheses of interest are the following: (1) the KD alters the nature, and/or degree, of energy metabolism in the brain -- therefore altering brain excitability; (2) the KD leads to changes in cell (neuronal and perhaps glial) properties, which decrease excitability and dampen epileptiform discharge; (3) the KD induces changes in neurotransmitter function and synaptic transmission -- thus altering inhibitory-excitatory balance and discouraging hyper-synchronization; (4) the KD is associated with changes in a variety of circulating factors which act as neuromodulators that can regulate CNS excitability; and (5) the KD gives rise to alterations in brain extracellular milieu, which serve to depress excitability and synchrony. An understanding of the mechanism underlying KD antiepileptic efficacy will help us not only to optimize the clinical use of the ketogenic diet, but also to develop novel antiepileptic treatments.
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Affiliation(s)
- P A Schwartzkroin
- Department of Neurological Surgery and Physiology/Biophysics, University of Washington, Seattle 98195-6470, USA.
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Foster TC. Involvement of hippocampal synaptic plasticity in age-related memory decline. BRAIN RESEARCH. BRAIN RESEARCH REVIEWS 1999; 30:236-49. [PMID: 10567726 DOI: 10.1016/s0165-0173(99)00017-x] [Citation(s) in RCA: 239] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
This article examines the functional significance of Ca(2+)-dependent synaptic plasticity in relation to compromised memory function during aging. Research characterizing an age-related decline in memory for tasks that require proper hippocampal function is summarized. It is concluded that aged animals possess the mechanisms necessary for memory formation, and memory deficits, including rapid forgetting, result from more subtle changes in memory processes for memory storage or maintenance. A review of experimental studies concerning changes in hippocampal neural plasticity over the course of aging indicates that, during aging, there is a shift in mechanisms that regulate the thresholds for synaptic modification, including Ca(2+) channel function and subsequent Ca(2+)-dependent processes. The results, combined with theoretical considerations concerning synaptic modification thresholds, provide the basis for a model of age-related changes in hippocampal synaptic function. The model is employed as a foundation for interpretation of studies examining therapeutic intervention in age-related memory decline. The possible role of altered synaptic plasticity thresholds in learning and memory deficits suggests that treatments that modify synaptic plasticity may prove fruitful for the development of early therapeutic interventions in age-related neurodegenerative diseases.
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Affiliation(s)
- T C Foster
- Department of Pharmacology, College of Medicine, University of Kentucky, MS-305 UKMC, Lexington, KY, USA.
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