Phospholipase A2 activation by melittin enhances spontaneous glutamatergic excitatory transmission in rat substantia gelatinosa neurons

Yue, Haosong; Fujita, Teizo; Kumamoto, Eiichi

doi:10.1016/j.neuroscience.2005.05.040

Cited by 32 publications

(33 citation statements)

References 51 publications

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“…These sEPSCs and sIPSCs were not significantly affected in both frequency and amplitude by the voltage-gated Na ϩ channel blocker TTX (0.5 M), as reported previously (Fujita et al 2009;Liu et al 2008;Luo et al 2002b;Yue et al 2005). This indicated that all of them occurred without the propagation of spikes from cell soma, whose neuron is presynaptic to SG neurons, to the terminals, resulting in spontaneous releases.…”

Section: Methodssupporting

confidence: 85%

“…vitro for more than 12 h, and recordings could be made from single SG neurons for up to 4 h. All SG neurons tested had resting membrane potentials that were more negative than Ϫ55 mV (when measured in a current-clamp mode) and exhibited glutamatergic sEPSCs and GABAergic and glycinergic sIPSCs, as shown previously (see Fujita et al 2009;Fujita and Kumamoto 2006;Lao et al 2001;Liu et al 2008;Luo et al 2002b;Yang et al 2004;Yue et al 2005). These sEPSCs and sIPSCs were not significantly affected in both frequency and amplitude by the voltage-gated Na ϩ channel blocker TTX (0.5 M), as reported previously (Fujita et al 2009;Liu et al 2008;Luo et al 2002b;Yue et al 2005).…”

Section: Methodssupporting

confidence: 58%

“…Superfusing nominally Ca 2ϩ -free, high-Mg 2ϩ (5 mM) Krebs solution itself reduced the sEPSC frequency, as observed in the superficial spinal dorsal horn (Hori et al 1992;Yue et al 2005). sEPSC frequency and amplitude in the Ca 2ϩ -free Krebs solution were, respectively, 86 Ϯ 2% (P Ͻ 0.01) and 100 Ϯ 1% (P Ͼ 0.05) of those (10.9 Ϯ 2.2 Hz and 10.9 Ϯ 0.5 pA, n ϭ 10) in normal Krebs solution.…”

Section: Methodsmentioning

confidence: 93%

“…Adult rat spinal cord slice preparations were obtained in a manner similar to that described previously (Fujita et al 2009;Fujita and Kumamoto 2006;Yue et al 2005). In brief, adult male Sprague-Dawley rats (6 -8 wk old, 200 -300 g) were anesthetized with urethane (1.5 g/kg body wt ip), and a laminectomy was performed to extract a lumbosacral spinal cord enlargement (L1-S3).…”

Section: Methodsmentioning

confidence: 99%

“…The SG was identified as a translucent band under a binocular microscope with light transmitted from below, as shown previously (Fujita et al 2009;Fujita and Kumamoto 2006;Yue et al 2005). Blind whole cell voltage-clamp recordings were performed from neurons located at the center of SG to avoid recordings from the laminae I and III neurons.…”

Section: Methodsmentioning

confidence: 99%

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Biphasic modulation by galanin of excitatory synaptic transmission in substantia gelatinosa neurons of adult rat spinal cord slices

Yue

Fujita

Kumamoto

2011

Journal of Neurophysiology

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Yue HY, Fujita T, Kumamoto E. Biphasic modulation by galanin of excitatory synaptic transmission in substantia gelatinosa neurons of adult rat spinal cord slices. J Neurophysiol 105: 2337-2349, 2011. First published March 16, 2011 doi:10.1152/jn.00991.2010.-Although intrathecally administrated galanin modulates nociceptive transmission in a biphasic manner, this has not been fully examined previously. In the present study, the action of galanin on synaptic transmission in the substantia gelatinosa (SG) neurons of adult rat spinal cord slices was examined, using the whole cell patch-clamp technique. Galanin concentration-dependently increased the frequency of spontaneous excitatory postsynaptic current (EPSC; EC 50 ϭ 2.0 nM) without changing the amplitude, indicating a presynaptic effect. This effect was reduced in a Ca 2ϩ -free, or voltage-gated Ca 2ϩ channel blocker La 3ϩ -containing Krebs solution and was produced by a galanin type-2/3 receptor (GalR2/R3) agonist, galanin 2-11, but not by a galanin type-1 receptor (GalR1) agonist, M617. Galanin also concentration-dependently produced an outward current at Ϫ70 mV (EC 50 ϭ 44 nM), although this appeared to be contaminated by a small inward current. This outward current was mimicked by M617, but not by galanin 2-11. Moreover, galanin reduced monosynaptic A␦-fiber-and C-fiber-evoked EPSC amplitude; the former reduction was larger than the latter. A similar action was produced by galanin 2-11, but not by M617. Spontaneous and focally evoked inhibitory (GABAergic and glycinergic) transmission was unaffected by galanin. These findings indicate that galanin at lower concentrations enhances the spontaneous release of L-glutamate from nerve terminals by Ca 2ϩ entry from the external solution following GalR2/R3 activation, whereas galanin at higher concentrations also produces a membrane hyperpolarization by activating GalR1. Moreover, galanin reduces L-glutamate release onto SG neurons from primary afferent fibers by activating GalR2/R3. These effects could partially contribute to the behavioral effect of galanin. pain; patch clamp; spinal dorsal horn GALANIN, a 29/30-amino acid peptide, was first extracted from porcine upper intestines in 1983 (Tatemoto et al. 1983). Subsequently, this peptide was reported to extensively exist in the peripheral and central nervous systems (CNS) (Lang et al. 2007). Recently, it was established that galanin serves as a neurotransmitter or neuromodulator in various physiological functions, including feeding and pain (Hökfelt 2005;Lang et al. 2007;Liu and Hökfelt 2002). There are three types of G protein-coupled metabotropic receptors (GalR1, GalR2, GalR3) for galanin (Lang et al. 2007).There is much evidence demonstrating that galanin plays a role in regulating nociceptive transmission to the spinal dorsal horn from the periphery. First, galanin-immunoreactivity, GalR1, GalR2, and GalR3 mRNAs and proteins exist in the rat The substantia gelatinosa (SG; lamina II of Rexed) of the spinal dorsal horn is thought to play an important role in ...

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Section: Methodssupporting

confidence: 85%