Decreased ability of rat temporal hippocampal CA1 region to produce long-term potentiation

Papatheodoropoulos, Costas; Kostopoulos, George

doi:10.1016/s0304-3940(99)01002-2

Cited by 119 publications

(95 citation statements)

References 22 publications

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“…These studies have demonstrated that the dorsal hippocampus encodes spatial memory, whereas the ventral sector processes information related to the motivational and homeostatic state of the animal (Moser and Moser, 1998). In support of this hypothesis, it was shown, both in vivo (Maruki et al, 2001) and in vitro (Papatheodoropoulos and Kostopoulos, 2000;Colgin et al, 2004;Maggio and Segal, 2007), that the ability to evoke short-and long-term plasticity differs between DH and VH. Specifically, in VH, the magnitude of long-term potentiation (LTP), a cellular model of learning and memory (Bliss and Collingridge, 1993), is significantly smaller than LTP elicited in the DH (Maggio and Segal, 2007).…”

Section: Introductionmentioning

confidence: 87%

Striking Variations in Corticosteroid Modulation of Long-Term Potentiation along the Septotemporal Axis of the Hippocampus

Maggio¹,

Segal²

2007

J. Neurosci.

211

183

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The ability to express long-term potentiation (LTP) of reactivity to afferent stimulation along the septotemporal axis was explored in transverse rat hippocampal slices. The ventral pole of the hippocampus (VH) was found to be much impaired in ability to express LTP compared with the rest of the hippocampus. An exposure to acute stress before the rat was killed reversed this trend, and slices from VH now expressed a large LTP, whereas in the rest of the hippocampus, it was much suppressed. The enhanced LTP in VH was mediated by activation of a mineralocorticoid receptor (MR), whereas the suppressed LTP was mediated by activation of a glucocorticoid receptor, and indeed selective agonists of the respective steroid receptors mimicked the effects of stress, whereas selective antagonists blocked them. The MR-enhanced LTP in VH was not mediated by activation of the NMDA receptor but by enhancement of voltage-gated calcium channels. Because the VH has an unique efferent system to the hypothalamus, these results indicate that stress may activate this system while suppressing the ability of the rest of the hippocampus to express plastic properties under stressful conditions.

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Section: Introductionmentioning

confidence: 87%

Striking Variations in Corticosteroid Modulation of Long-Term Potentiation along the Septotemporal Axis of the Hippocampus

Maggio¹,

Segal²

2007

J. Neurosci.

211

183

View full text Add to dashboard Cite

show abstract

“…In support of this assumption, it was shown, both in vivo (Maruki et al, 2001) and in vitro (Papatheodoropoulos and Kostopoulos, 2000;Colgin et al, 2004a;Maggio and Segal, 2007a), that the ability to evoke short-and long-term plasticity differs between dorsal hippocampus (DH) and ventral hippocampus (VH). Specifically, in the VH, the magnitude of LTP was significantly smaller than that elicited in the DH.…”

Section: Introductionmentioning

confidence: 91%

Differential Corticosteroid Modulation of Inhibitory Synaptic Currents in the Dorsal and Ventral Hippocampus

Maggio¹,

Segal²

2009

J. Neurosci.

113

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Corticosterone has been known to mediate the effects of stress on cognitive functions associated with the hippocampus. Acting at mineralocorticosteroid receptors (MRs) and glucocorticosteroid receptors (GRs), corticosterone exerts several effects in the hippocampus and elsewhere. Assuming that there are major functional differences between the dorsal hippocampus (DH) and ventral hippocampus (VH), and that these may be regulated by local interneurons, we analyzed the action of corticosterone on inhibitory synaptic currents in patch-clamped pyramidal neurons, recorded in acute slices of DH and VH. Corticosterone, through activation of MRs, reduced the frequency of spontaneous IPSCs in VH but not in DH neurons, and markedly suppressed paired-pulse facilitation of evoked inhibitory synaptic currents. These effects were mimicked by aldosterone, an MR agonist, and were blocked by an MR antagonist. In contrast, corticosterone caused an increase in the magnitude of IPSCs in both the DH and VH via its activation of GRs. This effect was mimicked by a GR agonist, dexamethasone, which produced a slow-onset, large potentiation reaching a peak within 45-60 min after onset of perfusion, and was blocked by a GR antagonist. The amplitude of mIPSCs was markedly increased by the GR agonist, indicating a synaptic locus of effect. These results indicate that corticosterone has a dual action, which may underlie the differential functional effects of stress hormones in the DH and VH.

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“…The interesting challenge ahead will be to assess whether these patterns of molecular expression translate into specific functional properties along the hippocampal long axis. The expression profiles of genes encoding adhesion molecules and ion channels 32,43 may determine intrinsic electrophysiological properties of discrete hippocampal neuronal populations, such as the differences in neuronal excitability 45 and synaptic plasticity [46][47] that have been detected along the long axis. For example, hyperpolarisation-activated cation channels HCN1 and HCN2, which mediate hyperpolarization-activated currents (I h ) currents, exhibit dorsoventral expression differences 48 and are important for a spatial function that is dorsoventrally graded [49][50][51] .…”

Section: Gene Expression Along the Long Axismentioning

confidence: 99%

Functional organization of the hippocampal longitudinal axis

Witter²,

et al. 2014

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The precise functional role of the hippocampus remains a topic of much debate. According to a dominant view, the dorsal/posterior hippocampus is implicated in memory and spatial navigation and the ventral/anterior hippocampus mediates anxietyrelated behaviours. However, this 'dichotomy view' may need revision. Gene expression studies demonstrate multiple functional domains along the hippocampal long axis, which often exhibit sharply demarcated borders. By contrast, anatomical studies and electrophysiological recordings in rodents suggest that the long-axis is organized along a gradient. Together, these observations suggest a model in which functional long-axis gradients are superimposed on discrete functional domains. This model provides a potential framework to explain and test the multiple functions ascribed to the hippocampus.The hippocampus is a medial temporal lobe structure critically involved in episodic memory and spatial navigation [1][2][3][4][5][6][7] . Its long, curved form is present across all mammalian orders and runs along a dorsal (septal) to ventral (temporal) axis in rodents, corresponding to a posteriorto-anterior axis in humans (FIG. 1a-b). The same basic intrinsic circuitry is maintained throughout the long axis and across species (FIG. 1c). Despite this conserved intrinsic circuitry, the dorsal and ventral portions have different connectivities with cortical and subcortical areas, and this has long posed a question as to whether the hippocampus is functionally uniform along this axis. Here we review cross-species data that show how the seemingly disparate functions ascribed to the hippocampus can be accommodated by a model in which different functional properties exist along the longitudinal axis.The severe memory impairment suffered by patient H.M. following bilateral hippocampal resection 1 led to intensive study 8 of patients and animal models with hippocampal damage, with an ensuing characterisation of hippocampal function in terms of declarative memory 2 , encompassing both episodic and semantic memory. At the same time, however, evidence emerged for a hippocampal role in spatial memory, based on the discovery of hippocampal 'place cells' 9,10 and the demonstration that hippocampal lesions impair spatial memory 4 . Both the declarative memory hypothesis 11 and the spatial mapping hypothesis 12 of hippocampal function proposed a unitary model in which the entire hippocampus is dedicated

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Decreased ability of rat temporal hippocampal CA1 region to produce long-term potentiation

Cited by 119 publications

References 22 publications

Striking Variations in Corticosteroid Modulation of Long-Term Potentiation along the Septotemporal Axis of the Hippocampus

Striking Variations in Corticosteroid Modulation of Long-Term Potentiation along the Septotemporal Axis of the Hippocampus

Differential Corticosteroid Modulation of Inhibitory Synaptic Currents in the Dorsal and Ventral Hippocampus

Functional organization of the hippocampal longitudinal axis

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