Low‐frequency stimulation of the temporoammonic pathway induces heterosynaptic disinhibition in the subiculum

Fidzinski, Pawel; Wawra, Matthias; Dugladze, Tamar; Gloveli, Tengis; Heinemann, Uwe; Behr, Jüergen

doi:10.1002/hipo.20791

Cited by 4 publications

(2 citation statements)

References 61 publications

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“…As in all experiments GABA A receptor-mediated transmission was blocked by bicuculline (5-10 µM), the concentration of MgSO 4 and CaCl 2 was elevated to 4 mM each in the recording medium in order to prevent epileptiform discharges [27]–[29]. In previous work we showed that increased Mg 2+ - and Ca 2+ -levels as well as blockade of inhibition are not related to bursting [30], [31].…”

Section: Methodsmentioning

confidence: 84%

5-HT4-Receptors Modulate Induction of Long-Term Depression but Not Potentiation at Hippocampal Output Synapses in Acute Rat Brain Slices

et al. 2014

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The subiculum is the principal target of CA1 pyramidal cells and mediates hippocampal output to various cortical and subcortical regions of the brain. The majority of subicular pyramidal cells are burst-spiking neurons. Previous studies indicated that high frequency stimulation in subicular burst-spiking cells causes presynaptic NMDA-receptor dependent long-term potentiation (LTP) whereas low frequency stimulation induces postsynaptic NMDA-receptor-dependent long-term depression (LTD). In the present study, we investigate the effect of 5-hydroxytryptamine type 4 (5-HT4) receptor activation and blockade on both forms of synaptic plasticity in burst-spiking cells. We demonstrate that neither activation nor block of 5-HT4 receptors modulate the induction or expression of LTP. In contrast, activation of 5-HT4 receptors facilitates expression of LTD, and block of the 5-HT4 receptor prevents induction of short-term depression and LTD. As 5-HT4 receptors are positively coupled to adenylate cyclase 1 (AC1), 5-HT4 receptors might modulate PKA activity through AC1. Since LTD is blocked in the presence of 5-HT4 receptor antagonists, our data are consistent with 5-HT4 receptor activation by ambient serotonin or intrinsically active 5-HT4 receptors. Our findings provide new insight into aminergic modulation of hippocampal output.

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Section: Methodsmentioning

confidence: 84%

5-HT4-Receptors Modulate Induction of Long-Term Depression but Not Potentiation at Hippocampal Output Synapses in Acute Rat Brain Slices

et al. 2014

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“…Of relevance to the present study, the term temporoammonic pathway (“TA path”) has been widely adopted in physiological studies (Maccaferri and McBain, 1995 ; Dvorak-Carbone and Schuman, 1999 ; Ang et al, 2005 ; Fidzinski et al, 2011 ; Booth et al, 2016 ). This term is used to refer to a direct entorhinal projection to CA1 and these fibers are discussed as though they are independent from PP (Dvorak-Carbone and Schuman, 1999 ).…”

Section: Discussionmentioning

confidence: 99%

A Comparison of Different Slicing Planes in Preservation of Major Hippocampal Pathway Fibers in the Mouse

et al. 2017

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The hippocampus plays a critical role in learning and memory and higher cognitive functions, and its dysfunction has been implicated in various neuropathological disorders. Electrophysiological recording undertaken in live brain slices is one of the most powerful tools for investigating hippocampal cellular and network activities. The plane for cutting the slices determines which afferent and/or efferent connections are best preserved, and there are three commonly used slices: hippocampal-entorhinal cortex (HEC), coronal and transverse. All three slices have been widely used for studying the major afferent hippocampal pathways including the perforant path (PP), the mossy fibers (MFs) and the Schaffer collaterals (SCs). Surprisingly, there has never been a systematic investigation of the anatomical and functional consequences of slicing at a particular angle. In the present study, we focused on how well fiber pathways are preserved from the entorhinal cortex (EC) to the hippocampus, and within the hippocampus, in slices generated by sectioning at different angles. The postmortem neural tract tracer 1,1′-dioctadecyl-3,3,3′3′-tetramethylindocarbocyanine perchlorate (DiI) was used to label afferent fibers to hippocampal principal neurons in fixed slices or whole brains. Laser scanning confocal microscopy was adopted for imaging DiI-labeled axons and terminals. We demonstrated that PP fibers were well preserved in HEC slices, MFs in both HEC and transverse slices and SCs in all three types of slices. Correspondingly, field excitatory postsynaptic potentials (fEPSPs) could be consistently evoked in HEC slices when stimulating PP fibers and recorded in stratum lacunosum-moleculare (sl-m) of area CA1, and when stimulating the dentate granule cell layer (gcl) and recording in stratum lucidum (sl) of area CA3. The MF evoked fEPSPs could not be recorded in CA3 from coronal slices. In contrast to our DiI-tracing data demonstrating severely truncated PP fibers in coronal slices, fEPSPs could still be recorded in CA1 sl-m in this plane, suggesting that an additional afferent fiber pathway other than PP might be involved. The present study increases our understanding of which hippocampal pathways are best preserved in the three most common brain slice preparations, and will help investigators determine the appropriate slices to use for physiological studies depending on the subregion of interest.

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High-frequency stimulation of the temporoammonic pathway induces input-specific long-term potentiation in subicular bursting cells

et al. 2012

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Low‐frequency stimulation of the temporoammonic pathway induces heterosynaptic disinhibition in the subiculum

Cited by 4 publications

References 61 publications

5-HT4-Receptors Modulate Induction of Long-Term Depression but Not Potentiation at Hippocampal Output Synapses in Acute Rat Brain Slices

5-HT4-Receptors Modulate Induction of Long-Term Depression but Not Potentiation at Hippocampal Output Synapses in Acute Rat Brain Slices

A Comparison of Different Slicing Planes in Preservation of Major Hippocampal Pathway Fibers in the Mouse

High-frequency stimulation of the temporoammonic pathway induces input-specific long-term potentiation in subicular bursting cells

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