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Low frequency stimulation induces NMDA receptor dependent perforant path-dentate gyrus synaptic potentiation
| Content Provider | Semantic Scholar |
|---|---|
| Author | Miyamoto, Daisuke Nomura, Hiroshi Matsuki, Norio |
| Copyright Year | 2011 |
| Abstract | s / Neuroscience Research 71S (2011) e108–e415 e113 deprivation on the development of GABAergic innervation is not thoroughly examined, although previous works have demonstrated that sensory deprivation during critical period reduces the number of parvalbumin-positive (PV) interneurons and the inhibitory perisomatic boutons in the layer 4. Here, we examined whether the maturation of the PV interneurons and their perisomatic innervations in the barrel cortex are influenced by different length of sensory deprivation. All major vibrissae (whiskers) on the right side of the snout were trimmed within 1 mm of the skin every day using scissors from the day of birth (P0) to P14, P0–P21, P0–P28 or P21–P28, and counted the number of glutamic acid decarboxylase 67 (GAD67)-positive perisomatic boutons and PV interneurons. Whisker trimming did not reduce the number of PV interneurons and GAD67-positive perisomatic boutons in any layers of the barrel cortex at P14 and P21. On the other hand, the number of PV interneurons reduced at P28 in layer 4, but not in layers 2/3 and 5. Furthermore, the number of GAD67-positive boutons per one neuron reduced in layer 4, but not in layers 2/3 and 5. To examine the role of sensory experience in the later period of development on the maturation of PV interneurons, we trimmed whiskers from P21 to P28. There was no difference in the number of PV interneurons between sensory-deprived and non-deprived barrel cortices. However, the density of GAD67-positive boutons increased in layers 4 and 2/3. The reduction of PV interneurons and GAD67-positive boutons in layer 4 by whisker trimming from P0 to P28 is consistent with the previous studies. However, our results suggest that sensory deprivation in the later period of development exert different effect on the development of laminar specific GABAergic innervation in the barrel cortex. doi:10.1016/j.neures.2011.07.478 P2-b03 Low frequency stimulation induces NMDA receptor dependent perforant path-dentate gyrus synaptic potentiation Daisuke Miyamoto , Hiroshi Nomura, Norio Matsuki Lab Chem Pharmacol, Grad Sch Pharm Sci, Univ of Tokyo, Tokyo, Japan For investigation of synaptic plasticity, high frequency stimulation, like 100 Hz tetanus stimulation, is widely used for induction of synaptic potentiation. However, mean firing rate of the dentate granule cell is much lower. The purpose of our experiments is to reveal the synaptic potentiation induced by low frequency stimulation. In urethane anesthetized rats, medial perforant path was stimulated and evoked synaptic inputs were recorded as fEPSP in the dentate gyrus. Baseline synaptic transmission was stably recorded with stimuli per 20 s (0.05 Hz). Decreasing the stimulation frequency from once per 20 s to once per 300 s (0.0033 Hz) for 3 h potentiated fEPSP slope. Cessation of the stimulation for 3 hours and then restarted the stimulation with once per 20 s did not modify fEPSP slope. Synaptic potentiation was dependent on low frequency evoked inputs. The synaptic potentiation was blocked by intrahippocampal injection of AP5, an antagonist of NMDA receptors. This result indicates that NMDA receptors are important for synaptic potentiation induced by low frequency stimulation. This new type of synaptic potentiation adds the diversity of the synaptic plasticity. doi:10.1016/j.neures.2011.07.479 P2-b04 Correlated activation of dopamine receptor is an essential for associative synaptic plasticity relevant to olfactory aversive memory Kohei Ueno 1 , Shintaro Naganos 1,2, Minoru Saitoe 1 1 Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan 2 Department of Biological Sciences, Tokyo Metropolitan University, Tokyo, Japan During olfactory aversive learning in Drosophila melanogaster, odor and shock information are delivered by the projection neurons (PNs) and ascending fiber from ventral nerve code (AFV), respectively, and associated in the mushroom body (MB) to form olfactory memory. Using Ca++ imaging analyses in isolated brain, we have previously demonstrated that simultaneous stimulation of PNs and AFV forms long-term facilitation (LTF) of PN-induced Ca++ responses in the MBs and suggest that this LTF at PN-MB synapse is relevant to olfactory aversive memory. However, molecular and physiological basis of PN-MB LTF remains unclear. We report here that the PNand AFVinduced MB responses are mediated by acetylcholine receptors (AChRs) and NMDA receptors (dNRs), respectively, and inhibition of these receptors during induction of LTF, simultaneous stimulation of PN and AFV, suppressed formation of PN-MB LTF. Type I dopamine receptor (D1R) plays crucial role for olfactory aversive learning and thought to mediate shock information to the MBs. However, neither genetical nor pharmacological inhibition of D1R suppressed AFV-induced MB responses. Notwithstanding, inhibition of D1R during LTF induction also blocked formation of PN-MB LTF, although synergistic increase in Ca++ responses during simultaneous stimulation of PN and AFV is not attenuated. Our results suggest that correlated activation of D1R during induction phase is required for formation of PN-MB LTF. Research fund: KAKENHI 20115006 and 40332556. doi:10.1016/j.neures.2011.07.480 P2-b05 Stratum oriens stimulation-induced enhancement of long-term potentiation at Schaffer collaterals-CA1 synapses shows a dependency on intensity of stimuli to the stratum oriens in rat hippocampus Etsuko Suzuki , Takashi Okada Dept. Psychol., Sophia Univ., Tokyo, Japan Activation of acetylcholine receptors modulates hippocampal neurotransmission and synaptic plasticity, which is important for learning and memory. In particular, muscarinic acetylcholine receptor (mAChR) activation enhances hippocampal long-term potentiation (LTP) in vivo and in vitro. Previously, it is reported that the preceding electrical stimulation to the stratum oriens, which activates mAChRs results in the enhancement of tetanus-induced LTP and lowers the threshold of LTP induction at hippocampal Schaffer collaterals (SC)-CA1 synapses. Here, we examined whether this enhancement of SC-CA1 LTP depends on the intensity of stimuli to the stratum oriens. Hippocampal slices were obtained from three-week-old male Wistar rats and field excitatory postsynaptic potentials (fEPSPs) were recorded from SC-CA1 synapses. Stimuli to the stratum oriens were set to intensities that evoked fEPSPs at the maximal value or about 50% of the maximal value of the initial slope of fEPSPs at the stratum oriens-CA1 synapses. The tetanic stimulation (100 Hz, 1 s) to SC induced stable LTP at SC-CA1 synapses. When electrical stimulation (40 Hz, 0.5 s) with maximal intensity was applied to the stratum oriens 30 s before tetanic stimulation to SC, the magnitude of SC-CA1 LTP was significantly enhanced compare to that of those without stratum oriens stimulation. However, if the intensity of stimuli to the stratum oriens was set to elicit about 50% of the maximal value of the initial slope, the magnitude of tetanus-induced LTP was almost the same as that of tetanus-induced LTP without stratum oriens stimulation. Furthermore, electrical stimulation to the stratum oriens without tetanic stimulation to SC could not induce LTP at the SC-CA1 synapses. Taken together, the enhancement of LTP by stimulation to the stratum oriens is dependent on stimulus intensity and stimulation to stratum oriens itself cannot induce LTP at SC-CA1 synapses. doi:10.1016/j.neures.2011.07.481 P2-b06 Sigma-1 receptor stimulation by dehydroepiandeosterone (DHEA) ameliorates the cognitive deficits via CaMKII, PKC and ERK activities in olfactory bulbectomized mice Shigeki Moriguchi , Yui Yamamoto, Kohji Fukunaga Dept. Pharmacol., Grad. Sch. of Pharmaceut. Sci., Tohoku Univ. Sendai, Japan Dehydroepiandrosterone (DHEA) is the most abundant neurosteroid synthesized de novo in the central nervous system. We here demonstrated that sigma-1 receptor stimulation by DHEA improves cognitive function through activation of protein kinases in olfactory bulbectomized (OBX) mice. Repeat treatments with DHEA at 30 or 60 mg/kg p.o. for 7 days significantly improved spatial reference and fear-conditioned memory behaviors as assessed by Y-maze, novel object recognition and passive avoidance task in OBX mice. DHEA restored hippocampal LTP injured in OBX mice. DHEA treatment restored PKC (Ser-657) and NR1 (Ser-896) phosphorylation to the control levels in the hippocampal CA1 region in OBX mice. Likewise, DHEA treatment improved CaMKII (Thr-286) autophosphorylation and GluR1 (Ser-831) phosphorylation to the control levels. Furthermore, DHEA treatment stimulated and restored ERK and CREB (Ser-133) phosphorylation to the control levels. Finally, pretreatment with NE-100, sigma-1 receptor antagonist, significantly inhibited DHEA-induced memory-related behaviors and CaMKII, PKC and ERK activities in CA1. Taken together, sigma-1 receptor stimulation by DHEA ameliorates OBX-induced deficits in memory-related behaviors and impairment of LTP through activation of CaMKII, PKC and ERK in the hippocampal CA1 region. doi:10.1016/j.neures.2011.07.482 |
| File Format | PDF HTM / HTML |
| DOI | 10.1016/j.neures.2011.07.479 |
| Volume Number | 71 |
| Alternate Webpage(s) | https://api.elsevier.com/content/article/pii/S0168010211006626 |
| Alternate Webpage(s) | https://www.sciencedirect.com/science/article/pii/S0168010211006626?dgcid=api_sd_search-api-endpoint |
| Journal | Neuroscience Research |
| Language | English |
| Access Restriction | Open |
| Content Type | Text |
| Resource Type | Article |
