title: Prostaglandin E2-mediated upregulation of neuroexcitation and persistent tetrodotoxin-resistant Na(+) currents in Ah-type trigeminal ganglion neurons isolated from adult female rats.
abstract: Prostaglandin-E2 (PGE2) is a very important inflammatory mediator and PGE2-mediated neuroexcitation in sex-specific distribution of Ah-type trigeminal ganglion neurons (TGNs) isolated from adult female rats is not fully addressed. The whole-cell patch-clamp experiment was performed to verify the effects of PGE2, forskolin, and GPR30-selective agonist (G-1) on action potential (AP) and tetrodotoxin-resistant (TTX-R) Na(+) currents in identified Ah-type TGNs. The results showed that the firing frequency was increased in Ah- and C-types by PGE2, which was simulated by forskolin and inhibited by Rp-cyclic adenosine monophosphate (cAMP), while G-1 mimicked this effect only in Ah-types, which was abolished by GPR30-selective antagonist (G-15). Although the amplitude of AP was increased in Ah- and C-types, increased maximal upstroke velocity was confirmed only in Ah-types, suggesting distinct alternations in current density and/or voltage-dependent property of Na(+) channels. With 1.0 μM PGE2, TTX-R Na(+) currents were upregulated without changing the current-voltage relationship and voltage-dependent activation in C-types, however, the TTX-R Na(+) current was augmented in Ah-types, peaked voltage and the voltage-dependent activation were both shifted toward hyperpolarized direction with faster slope. Intriguingly, the low-threshold persistent TTX-R component was activated from -60 mV and increased almost double at -30 mV compared with ∼30-40% increment of TTX-R component being activated at ∼-10 mV. Additionally, the change in TTX-R component of Ah-types was equivalent well with that in C-type TGNs. Taken these data together, we conclude that PGE2 modulates the neuroexcitation via cAMP-mediated upregulation of TTX-R Na(+) currents in both cell-types with hormone-dependent feature, especially persistent TTX-R Na(+) currents in sex-specific distribution of myelinated Ah-type TGNs.
authors: Department of Neurology, The Fourth Affiliated Hospital of Harbin Medical University, Harbin, China. Electronic address: liuhuahyd@sina.com.
authors: H
authors: H
authors: Liu
authors: Department of Neurology, The First Affiliated Hospital of Harbin Medical University, Harbin, China.
authors: S-R
authors: SR
authors: Duan
mesh_terms: D000200:Action Potentials / Q000502:physiology; D000818:Animals; D015232:Dinoprostone / Q000378:metabolism*; D005260:Female; D018408:Patch-Clamp Techniques; D051381:Rats; D017207:Rats, Sprague-Dawley; D012727:Sex Characteristics; D026941:Sodium Channel Blockers / Q000494:pharmacology; D015222:Sodium Channels / Q000378:metabolism*; D013779:Tetrodotoxin / Q000494:pharmacology; D012668:Trigeminal Ganglion / Q000378:metabolism*; D015854:Up-Regulation
chemical_list: D026941:Sodium Channel Blockers; D015222:Sodium Channels; D013779:Tetrodotoxin; D015232:Dinoprostone
keywords: myelinated afferent; neuroexcitation; persistent tetrodotoxin-resistant sodium current; prostaglandin E(2); trigeminal ganglion neuron