RESUMEN
Because a rank-ordered recruitment of motor units occurs during isometric contraction of jaw-closing muscles, jaw-closing motoneurons (MNs) may be recruited in a manner dependent on their soma sizes or input resistances (IRs). In the dorsolateral part of the trigeminal motor nucleus (dl-TMN) in rats, MNs abundantly express TWIK (two-pore domain weak inwardly rectifying K channel)-related acid-sensitive-K(+) channel (TASK)-1 and TASK3 channels, which determine the IR and resting membrane potential. Here we examined how TASK channels are involved in IR-dependent activation/recruitment of MNs in the rat dl-TMN by using multiple methods. The real-time PCR study revealed that single large MNs (>35 µm) expressed TASK1 and TASK3 mRNAs more abundantly compared with single small MNs (15-20 µm). The immunohistochemistry revealed that TASK1 and TASK3 channels were complementarily distributed in somata and dendrites of MNs, respectively. The density of TASK1 channels seemed to increase with a decrease in soma diameter while there were inverse relationships between the soma size of MNs and IR, resting membrane potential, or spike threshold. Dual whole-cell recordings obtained from smaller and larger MNs revealed that the recruitment of MNs depends on their IRs in response to repetitive stimulation of the presumed Ia afferents. 8-Bromoguanosine-cGMP decreased IRs in small MNs, while it hardly changed those in large MNs, and subsequently decreased the difference in spike-onset latency between the smaller and larger MNs, causing a synchronous activation of MNs. These results suggest that TASK channels play critical roles in rank-ordered recruitment of MNs in the dl-TMN.
Asunto(s)
Neuronas Motoras/metabolismo , Canales de Potasio de Dominio Poro en Tándem/metabolismo , Canales de Potasio/metabolismo , Núcleo Motor del Nervio Trigémino/metabolismo , Animales , Tamaño de la Célula , GMP Cíclico/metabolismo , Dendritas/metabolismo , Femenino , Células HEK293 , Humanos , Masculino , Potenciales de la Membrana/fisiología , Ratones , Neuronas Motoras/citología , Proteínas del Tejido Nervioso , Oocitos , Canales de Potasio/genética , Canales de Potasio de Dominio Poro en Tándem/genética , ARN Mensajero/metabolismo , Ratas Wistar , Técnicas de Cultivo de Tejidos , Núcleo Motor del Nervio Trigémino/citología , Xenopus laevisRESUMEN
The characteristics of municipal wastewater treatment by electrolysis, ozonation, and combination processes of electrolysis and aeration using three gaseous species (nitrogen [N2], oxygen [O2], and ozone [O3]) were discussed in this research using ruthenium oxide (RuO2)-coated titanium anodes and stainless-steel (SUS304) cathodes. Electrolysis and electrolysis with nitrogen aeration were characterized by a rapid decrease in 5-day biochemical oxygen demand (BODs) and total nitrogen and a slow decrease in chemical oxygen demand (COD). In contrast, ozonation, electrolysis with oxygen aeration, and electrolysis with ozone aeration were characterized by transformation of persistent organic matter to biodegradable matter and preservation of total nitrogen. The best energy efficiency in removing BOD5 and total nitrogen was demonstrated by electrolysis, as a result of direct anodic oxidation and indirect oxidation with free chlorine produced from the chloride ion (Cl-) at the anodes. However, electrolysis with ozone aeration was found to be superior to the other processes, in terms of its energy efficiency in removing COD and its ability to remove COD completely, as a result of hydroxyl radical (*OH) production via cathodic reduction of ozone.
Asunto(s)
Electrólisis , Residuos Industriales , Ozono/química , Eliminación de Residuos Líquidos/métodos , Cloruros/química , Ciudades , Electroquímica , Electrodos , Radical Hidroxilo/química , Nitrógeno/química , Nitrógeno/aislamiento & purificación , Compuestos Orgánicos/química , Compuestos Orgánicos/aislamiento & purificación , Oxígeno/química , Oxígeno/metabolismo , Compuestos de Rutenio/química , Factores de Tiempo , Titanio/químicaRESUMEN
The advanced oxidation effect of ozonation combined with electrolysis (electrolysis-ozonation) was discussed through the treatment of 4-chlorobenzoic acid (4-CBA) as a hydroxyl radical probe. The mechanism of hydroxyl radical production by electrolysis-ozonation process was also estimated with a mathematical model. The experimental results revealed that the electrolysis-ozonation process had a synergistic effect on the degradation of 4-CBA. The advanced oxidation effect of electrolysis-ozonation was inferred from standard potentials of relevant electrochemical reactions and mathematical model analysis to be mainly attributed to ()O(3)(-) promotion of O(3) at the cathodes. An increase in electric current improved the degradation rate of 4-CBA. However, the pseudo-first order degradation rate constant reached a plateau at high electric current densities, as ()O(3)(-) promotion of O(3) at the cathodes was regulated by O(3) transport process from the bulk to the cathodes in the range exceeding an electric current density of 10 Am(-2). Accordingly, the balance of O(3) transport flux and electric current is important for the efficient operation of the electrolysis-ozonation reactor.