• 제목/요약/키워드: GABAergic terminals

검색결과 5건 처리시간 0.019초

Effects of Zinc on Spontaneous Miniature GABA Release in Rat Hippocampal CA3 Pyramidal Neurons

  • Choi, Byung-Ju;Jang, Il-Sung
    • The Korean Journal of Physiology and Pharmacology
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    • 제10권2호
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    • pp.59-64
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    • 2006
  • The effects of $Zn^{2+}$ on spontaneous glutamate and GABA release were tested in mechanically dissociated rat CA3 pyramidal neurons which retained functional presynaptic nerve terminals. The spontaneous miniature excitatory and inhibitory postsynaptic currents (mEPSCs and mIPSCs, respectively) were pharmacologically isolated and recorded using whole-cell patch clamp technique under voltage-clamp conditions. $Zn^{2+}$ at a lower concentration $(30{\mu}M)$ increased GABAergic mIPSC frequency without affecting mIPSC amplitude, but it decreased both mIPSC frequency and amplitude at higher concentrations $({\ge}300{\mu}M)$. In contrast, $Zn^{2+}$ (3 to $100{\mu}M$) did not affect glutamatergic mEPSCs, although it slightly decreased both mIPSC frequency and amplitude at $300{\mu}M$ concentration. Facilitatory effect of $Zn^{2+}$ on GABAergic mIPSC frequency was occluded either in $Ca^{2+}$-free external solution or in the presence of $100{\mu}M$ 4-aminopyridine, a non-selective $K^{+}$ channel blocker. The results suggest that $Zn^{2+}$ at lower concentrations depolarizes GABAergic nerve terminals by blocking $K^{+}$ channels and increases the probability of spontaneous GABA release. This $Zn^{2+}$-mediated modulation of spontaneous GABAergic transmission is likely to play an important role in the regulation of neuronal excitability within the hippocampal CA3 area.

Nitric Oxide Modulation of GABAergic Synaptic Transmission in Mechanically Isolated Rat Auditory Cortical Neurons

  • Lee, Jong-Ju
    • The Korean Journal of Physiology and Pharmacology
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    • 제13권6호
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    • pp.461-467
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    • 2009
  • The auditory cortex (A1) encodes the acquired significance of sound for the perception and interpretation of sound. Nitric oxide (NO) is a gas molecule with free radical properties that functions as a transmitter molecule and can alter neural activity without direct synaptic connections. We used whole-cell recordings under voltage clamp to investigate the effect of NO on spontaneous GABAergic synaptic transmission in mechanically isolated rat auditory cortical neurons preserving functional presynaptic nerve terminals. GABAergic spontaneous inhibitory postsynaptic currents (sIPSCs) in the A1 were completely blocked by bicuculline. The NO donor, S-nitroso-N-acetylpenicillamine (SNAP), reduced the GABAergic sIPSC frequency without affecting the mean current amplitude. The SNAP-induced inhibition of sIPSC frequency was mimicked by 8-bromoguanosine cyclic 3',5'-monophosphate, a membrane permeable cyclic-GMP analogue, and blocked by 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide, a specific NO scavenger. Blockade of presynaptic $K^+$ channels by 4-aminopyridine, a $K^+$ channel blocker, increased the frequencies of GABAergic sIPSCs, but did not affect the inhibitory effects of SNAP. However, blocking of presynaptic $Ca^{2+}$ channels by $Cd^{2+}$, a general voltage-dependent $Ca^{2+}$ channel blocker, decreased the frequencies of GABAergic sIPSCs, and blocked SNAP-induced reduction of sIPSC frequency. These findings suggest that NO inhibits spontaneous GABA release by activation of cGMP-dependent signaling and inhibition of presynaptic $Ca^{2+}$ channels in the presynaptic nerve terminals of A1 neurons.

흰쥐 시각교차위핵(suprachiasmatic nucleus)의 출생직후 GABA성 신경종말의 분포양상 (The postnatal distribution pattern of GABAergic terminals of the suprachiasmatic nucleus in rat)

  • 이성준
    • 대한수의학회지
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    • 제40권4호
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    • pp.661-664
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    • 2000
  • The present study was carried out to reveal the role of ${\gamma}$-aminobutylic acid(GABA) during postnatal period in rat. The suprachiasmatic nucleus(SCN) of hypothalamus has been known as the regulation center of circadian rhythm in the mammalians. In this study, we could find many GABAergic terminals in the SCN from day 1 to day 7 after birth. On the basis of these results, it can be said there are some kinds of inhibitory effects by GABA to the light stimulation of newborn rat.

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개의 교핵내 GABA성 신경세포 성분의 미세구조적 위치관찰 (Ultrastructural Localization of GABAergic Neuronal Components in the Dog Basilar Pons)

  • 이현숙
    • Applied Microscopy
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    • 제25권1호
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    • pp.65-74
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    • 1995
  • 개의 교핵내의 GABA를 함유한 억제성 신경세포의 연접부위를 전자현미경을 이용한 면역세포화학적 방법으로 조사하였다. 반응산물은 신경원의 핵부위나 가지돌기에서 관찰되었으며, 반응산물을 포함하고 있지 않은 신경종말이 이들과 비대칭형 연접을 형성하였다. 그 외에도 많은 수의 GABA성 신경종말이 관찰되었으며, 이들은 반응산물을 함유하지 않은 가지돌기와 대칭형 또는 비대칭형 연접을 형성하였다. 한편 축삭돌기-축삭돌기 연접에서는 연접후 유축사돌기 (axon-like processes)가 GABA-양성이었다. 이와 같은 관찰은 개의 교핵에 존재하는 억제성 개재신경원이 여러 수입계로부터의 정보를 통합하고, 이를 소뇌피질이나 소뇌핵에 전달함으로써, 대뇌-교핵-소뇌계의 신경경로에서 조절기능을 담당함을 뒷받침하는 것이다.

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The Electrophysiological Identification of the Cone- and the Rod- HCs Dissociated from Goldfish Retina

  • Paik, Sun-Sook;Park, Jin-Su;Song, Min-Su;Bai, Sun-Ho;Jung, Chang-Sub
    • 한국생물물리학회:학술대회논문집
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    • 한국생물물리학회 2003년도 정기총회 및 학술발표회
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    • pp.36-36
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    • 2003
  • Goldfish retina has been well studied to a great extent. In spite of that, electrical characteristics of dissociated horizontal cells(HCs) have not been identified in detail. Thus the cone-and the rod- HCs dissociated from goldfish retina were investigated electrophysiologically using whole-cell patch-clamping recording. To explore the basic electrical property, We examined voltage-dependent channels in all types of HCs. For the futher understanding of GABAergic pathway, the localization and distribution of GABA receptors was examined in cone- HCs including HC axon terminals(ATs).

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