Priming stimulation in the basolateral amygdala modulates synaptic plasticity in the rat dentate gyrus

The basolateral amygdala (BLA) has substantial effects on the neuronal transmission and synaptic plasticity processes through the dentate gyrus. Orexin neuropeptides play different roles in the sleep/wakefulness cycle, feeding, learning, and memory. The present study was conducted to investigate the function of the orexin receptors of the BLA in the hippocampal local interneuron circuits. For this, paired-pulse responses from dentate gyrus (DG) region were recorded. Within the procedure, SB-334867-A (12μg/0.5μl), and, TCS-OX2-29 (10μg/0.5μl (orexin 1 and 2 receptors antagonists, respectively), were administered into the both side of the BLA areas of the rat brain. Dimethyl sulfoxide (DMSO) was used as the solvent in the control animals with the volume of 0.5μl. Our data indicated that the paired-pulse (PP) responses were not affected by the inactivation of the orexin receptors of the BLA.

Download Full-text

Glucocorticoid receptors and β-adrenoceptors in basolateral amygdala modulate synaptic plasticity in hippocampal dentate gyrus, but not in area CA1

Neuropharmacology ◽

10.1016/j.neuropharm.2006.07.007 ◽

2007 ◽

Vol 52 (1) ◽

pp. 244-252 ◽

Cited By ~ 43

Author(s):

Rose-Marie Vouimba ◽

Dan Yaniv ◽

Gal Richter-Levin

Keyword(s):

Synaptic Plasticity ◽

Dentate Gyrus ◽

Glucocorticoid Receptors ◽

Basolateral Amygdala ◽

Hippocampal Dentate Gyrus ◽

Area Ca1

Download Full-text

The role of interaction between orexin receptors and β2 adrenergic receptors in basolateral amygdala in dentate gyrus synaptic plasticity in male rats

Brain Research Bulletin ◽

10.1016/j.brainresbull.2021.09.020 ◽

2021 ◽

Vol 177 ◽

pp. 164-171

Author(s):

Seyedeh Kebria Noorani ◽

Vida Hojati ◽

Esmaeil Akbari ◽

Simin Ehsani ◽

Takeshi Sakurai ◽

...

Keyword(s):

Synaptic Plasticity ◽

Dentate Gyrus ◽

Adrenergic Receptors ◽

Basolateral Amygdala ◽

Male Rats ◽

Orexin Receptors

Download Full-text

Neurofascin knock down in the basolateral amygdala mediates resilience of memory and plasticity in the dorsal dentate gyrus under stress

10.26226/morressier.5b31ec342afeeb001345b606 ◽

2018 ◽

Author(s):

Anne Albrecht ◽

Gal Richter-Levin ◽

Rinki Saha

Keyword(s):

Dentate Gyrus ◽

Basolateral Amygdala ◽

Knock Down

Download Full-text

Effects of Adult Neurogenesis on Synaptic Plasticity in the Rat Dentate Gyrus

Journal of Neurophysiology ◽

10.1152/jn.2001.85.6.2423 ◽

2001 ◽

Vol 85 (6) ◽

pp. 2423-2431 ◽

Cited By ~ 393

Author(s):

J. S. Snyder ◽

N. Kee ◽

J. M. Wojtowicz

Keyword(s):

Synaptic Plasticity ◽

Dentate Gyrus ◽

Adult Neurogenesis ◽

Long Term Potentiation ◽

Receptor Blocker ◽

Granule Neurons ◽

Term Potentiation ◽

Cell Recording ◽

Similar Preparation ◽

Nmda Receptor Blocker

Ongoing neurogenesis in the adult hippocampal dentate gyrus (DG) generates a substantial population of young neurons. This phenomenon is present in all species examined thus far, including humans. Although the regulation of adult neurogenesis by various physiologically relevant factors such as learning and stress has been documented, the functional contributions of the newly born neurons to hippocampal functions are not known. We investigated possible contributions of the newly born granule neurons to synaptic plasticity in the hippocampal DG. In the standard hippocampal slice preparation perfused with artificial cerebrospinal fluid (ACSF), a small (10%) long-term potentiation (LTP) of the evoked field potentials is seen after tetanic stimulation of the afferent medial perforant pathway (MPP). The induction of this ACSF-LTP is resistant to a N-methyl-d-aspartate (NMDA) receptor blocker,d,l-2-amino-5-phosphonovaleric acid (APV), but is completely prevented by ifenprodil, a blocker of NR2B subtype of NMDA receptors. In contrast, slices perfused with picrotoxin (PICRO), a GABA-receptor blocker, revealed a larger (40–50%), APV-sensitive but ifenprodil-insensitive LTP. The ACSF-LTP required lower frequency of stimulation and fewer stimuli for its induction than the PICRO-LTP. All these characteristics of ACSF-LTP are in agreement with the properties of the putative individual new granule neurons examined previously with the use of the whole cell recording technique in a similar preparation. A causal relationship between neurogenesis and ACSF-LTP was confirmed in experiments using low dose of gamma radiation applied to the brain 3 wk prior to the electrophysiological experiments. In these experiments, the new cell proliferation was drastically reduced and ACSF-LTP was selectively blocked. We conclude that the young, adult-generated granule neurons play a significant role in synaptic plasticity in the DG. Since DG is the major source of the afferent inputs into the hippocampus, the production and the plasticity of new neurons may have an important role in the hippocampal functions such as learning and memory.

Download Full-text

Reduced GluN1 in mouse dentate gyrus is associated with CA3 hyperactivity and psychosis-like behaviors

Molecular Psychiatry ◽

10.1038/s41380-018-0124-3 ◽

2018 ◽

Vol 25 (11) ◽

pp. 2832-2843 ◽

Cited By ~ 6

Author(s):

Amir Segev ◽

Masaya Yanagi ◽

Daniel Scott ◽

Sarah A. Southcott ◽

Jacob M. Lister ◽

...

Keyword(s):

Dentate Gyrus ◽

Basolateral Amygdala ◽

Pyramidal Neurons ◽

Mossy Fibers ◽

Model Systems ◽

Memory Processing ◽

Hippocampal Subfields ◽

Whole Cell Patch Clamp ◽

Hippocampal Activity

Abstract Recent findings from in vivo-imaging and human post-mortem tissue studies in schizophrenic psychosis (SzP), have demonstrated functional and molecular changes in hippocampal subfields that can be associated with hippocampal hyperexcitability. In this study, we used a subfield-specific GluN1 knockout mouse with a disease-like molecular perturbation expressed only in hippocampal dentate gyrus (DG) and assessed its association with hippocampal physiology and psychosis-like behaviors. First, we used whole-cell patch-clamp recordings to measure the physiological changes in hippocampal subfields and cFos immunohistochemistry to examine cellular excitability. DG-GluN1 KO mice show CA3 cellular hyperactivity, detected using two approaches: (1) increased excitatory glutamate transmission at mossy fibers (MF)-CA3 synapses, and (2) an increased number of cFos-activated pyramidal neurons in CA3, an outcome that appears to project downstream to CA1 and basolateral amygdala (BLA). Furthermore, we examined psychosis-like behaviors and pathological memory processing; these show an increase in fear conditioning (FC), a reduction in prepulse inhibition (PPI) in the KO animal, along with a deterioration in memory accuracy with Morris Water Maze (MWM) and reduced social memory (SM). Moreover, with DREADD vectors, we demonstrate a remarkably similar behavioral profile when we induce CA3 hyperactivity. These hippocampal subfield changes could provide the basis for the observed increase in human hippocampal activity in SzP, based on the shared DG-specific GluN1 reduction. With further characterization, these animal model systems may serve as targets to test psychosis mechanisms related to hippocampus and assess potential hippocampus-directed treatments.

Download Full-text

Levetiracetam Reduced the Basal Excitability of the Dentate Gyrus without Restoring Impaired Synaptic Plasticity in Rats with Temporal Lobe Epilepsy

Brain Sciences ◽

10.3390/brainsci10090634 ◽

2020 ◽

Vol 10 (9) ◽

pp. 634

Author(s):

Guillermo González-H ◽

Itzel Jatziri Contreras-García ◽

Karla Sánchez-Huerta ◽

Claudio M. T. Queiroz ◽

Luis Ricardo Gallardo Gudiño ◽

...

Keyword(s):

Synaptic Plasticity ◽

Temporal Lobe Epilepsy ◽

Dentate Gyrus ◽

Temporal Lobe ◽

Focal Epilepsy ◽

Chronic Phase ◽

Long Term Potentiation ◽

Excitatory Postsynaptic Potential ◽

Output Curve

Temporal lobe epilepsy (TLE), the most common type of focal epilepsy, affects learning and memory; these effects are thought to emerge from changes in synaptic plasticity. Levetiracetam (LEV) is a widely used antiepileptic drug that is also associated with the reversal of cognitive dysfunction. The long-lasting effect of LEV treatment and its participation in synaptic plasticity have not been explored in early chronic epilepsy. Therefore, through the measurement of evoked field potentials, this study aimed to comprehensively identify the alterations in the excitability and the short-term (depression/facilitation) and long-term synaptic plasticity (long-term potentiation, LTP) of the dentate gyrus of the hippocampus in a lithium–pilocarpine rat model of TLE, as well as their possible restoration by LEV (1 week; 300 mg/kg/day). TLE increased the population spike (PS) amplitude (input/output curve); interestingly, LEV treatment partially reduced this hyperexcitability. Furthermore, TLE augmented synaptic depression, suppressed paired-pulse facilitation, and reduced PS-LTP; however, LEV did not alleviate such alterations. Conversely, the excitatory postsynaptic potential (EPSP)-LTP of TLE rats was comparable to that of control rats and was decreased by LEV. LEV caused a long-lasting attenuation of basal hyperexcitability but did not restore impaired synaptic plasticity in the early chronic phase of TLE.

Download Full-text