P- and R-type Ca2+ channels regulating spinal glycinergic nerve terminals

Nonaka, Kiku; Murayama, Nobuki; Maeda, Megumi; Shoudai, Kiyomitsu; Shin, Min Chul; Akaike, Norio

doi:10.1016/j.toxicon.2010.01.020

Cited by 8 publications

(9 citation statements)

References 33 publications

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“…Effects of -agatoxin IVA. It is known that -AgTX inhibits P-and Q-type Ca 2ϩ channels at a very low concentration (2 nM) and at concentrations higher than 200 nM, respectively (Murakami et al 2002;Nonaka et al 2010;Reid et al 1997). At very high concentration (1 M), -AgTX also nonselectively blocks other Ca 2ϩ channel subtypes (Sidach and Mintz 2000).…”

Section: Resultsmentioning

confidence: 99%

Calcium channel subtypes on glutamatergic mossy fiber terminals synapsing onto rat hippocampal CA3 neurons

Shin

Nonaka

Yamaga

et al. 2018

Journal of Neurophysiology

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The current electrophysiological study investigated the functional roles of high- and low-voltage-activated Ca channel subtypes on glutamatergic small mossy fiber nerve terminals (SMFTs) that synapse onto rat hippocampal CA3 neurons. Experiments combining both the "synapse bouton" preparation and single-pulse focal stimulation technique were performed using the conventional whole cell patch configuration under voltage-clamp conditions. Nifedipine, at a high concentration, and BAY K 8644 inhibited and facilitated the glutamatergic excitatory postsynaptic currents (eEPSCs) that were evoked by 0.2-Hz stimulation, respectively. However, these drugs had no effects on spontaneous EPSCs (sEPSCs). Following the use of a high stimulation frequency of 3 Hz, however, nifedipine markedly inhibited eEPSCs at the low concentration of 0.3 µM. Moreover, ω-conotoxin GVIA and ω-agatoxin IVA significantly inhibited both sEPSCs and eEPSCs. Furthermore, SNX-482 slightly inhibited eEPSCs. R(-)-efonidipine had no effects on either sEPSCs or eEPSCs. It was concluded that glutamate release from SMFTs depends largely on Ca entry through N- and P/Q-type Ca channels and, to a lesser extent, on R-type Ca channels. The contribution of L-type Ca channels to eEPSCs was small at low-firing SMFTs but more significant at high-firing SMFTs. T-type Ca channels did not appear to be involved in neurotransmission at SMFTs. NEW & NOTEWORTHY Action potential-evoked glutamate release from small mossy fiber nerve terminals (SMFTs) that synapse onto rat hippocampal CA3 neurons is regulated by high-threshold but not low-threshold Ca channel subtypes. The functional contribution mainly depends on N- and P/Q-type Ca channels and, to a lesser extent, on R-type Ca channels. However, in SMFTs stimulated at a high 3-Hz frequency, L-type Ca channels contributed significantly to the currents. The present results are consistent with previous findings from fluorometric studies of large mossy fiber boutons.

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Section: Resultsmentioning

confidence: 99%

Calcium channel subtypes on glutamatergic mossy fiber terminals synapsing onto rat hippocampal CA3 neurons

Shin

Nonaka

Yamaga

et al. 2018

Journal of Neurophysiology

Self Cite

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“…As indicated above, the selective activation of a single excitatory glutamatergic (Yamamoto et al, 2011;Akaike et al, 2010) The depolarization of the nerve terminals triggered by Na channel activation results in subsequent Ca 2+ influx passing through voltage-dependent Ca channels (Nonaka et al, 2010;Jackson & Zhang, 1995). The application of 0.3μM TTX reversibly abolished GABAergic eIPSCs.…”

Section: General Properties Of Spontaneous and Evoked Transmitter Relmentioning

confidence: 95%

“…The L-, N-and P/Q subtypes of Ca 2+ channels were identified on the CA1 GABAergic nerve terminals and P-and R Ca 2+ channel subtypes on the SDCN glycinergic terminals (Nonaka et al, 2010). There is some Ca 2+ channel cooperativity in the individual terminals, and the different subtypes present all contribute to determining the total Ca 2+ influx associated with synaptic vesicle release.…”

Section: General Properties Of Spontaneous and Evoked Transmitter Relmentioning

confidence: 99%

“…These adherent synaptic boutons contain functional voltage-dependent ionic channels, various chemoreceptors, transporters, and 2nd messenger pathways, as also found in the postsynaptic neuron. To date, this 'synaptic bouton' preparation has been obtained from various brain regions in our laboratory, including: the Meynert's nuclei Arima et al, 2001), the basolateral amygdala (Koyama et al, 1999), the hippocampal CA1 and CA3 (Yamamoto et al, 2011) regions, the periaqueductal gray , the ventromedial hypothalamus (Jang et al, 2001), and the spinal sacral dorsal commissural nucleus (Akaike et al, 2010) and many other regions. A, B: Schematic illustration of the mechanical dissociation of rat hippocampal CA1 pyramidal neurons.…”

Section: Mechanical Dissociation Of Mammalian Cns Neuronsmentioning

confidence: 99%

“…Therefore, it is of interest to study the effects of BoNTs on fast neurotransmission at mammalian CNS terminals. Below, we describe the effects of A2 type botulinum toxin (A2NTX) on spontaneous and evoked neurotransmitter release at inhibitory (glycinergic or GABAergic) and excitatory (glutamatergic) synapses in rat spinal neurons using 'synaptic bouton' preparations (Akaike et al, 2010;Sakaguchi et al, 1981).…”

Section: Modulation Of Excitatory and Inhibitory Presynaptic Terminalmentioning

confidence: 99%

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