The Voltage-Gated Sodium Channel Na(v)1.8 Is Expressed in Human Sperm

The role of Na+ fluxes through voltage-gated sodium channels in the regulation of sperm cell function remains poorly understood. Previously, we reported that several genes encoding voltage-gated Na+ channels were expressed in human testis and mature spermatozoa. In this study, we analyzed the presence and function of the TTX-resistant VGSC a subunit Na(v)1.8 in human capacitated sperm cells. Using an RT-PCR assay, we found that the mRNA of the gene SCN10A, that encode Na-v1.8, was abundantly and specifically expressed in human testis and ejaculated spermatozoa. The Na-v1.8 protein was detected in capacitated sperm cells using three different specific antibodies against this channel. Positive immunoreactivity was mainly located in the neck and the principal piece of the flagellum. The presence of Na-v1.8 in sperm cells was confirmed by Western blot. Functional studies demonstrated that the increases in progressive motility produced by veratridine, a voltage-gated sodium channel activator, were reduced in sperm cells preincubated with TTX (10 mu M), the Na-v1.8 antagonist A-803467, or a specific Na-v1.8 antibody. Veratridine elicited similar percentage increases in progressive motility in sperm cells maintained in Ca2+-containing or Ca2+-free solution and did not induce hyperactivation or the acrosome reaction. Veratridine caused a rise in sperm intracellular Na+, [Na+](i), and the sustained phase of the response was inhibited in the presence of A-803467. These results verify that the Na+ channel Na-v1.8 is present in human sperm cells and demonstrate that this channel participates in the regulation of sperm function.

Estudio filológico-literario comparativo del relato del funeral de Augusto contado por el biógrafo Suetonio ("Aug."100) y por el historiador Tácito ("Ann."1.8-10)

[ES] Este trabajo se propone el análisis comparativo, bajo el punto de vista filológico y literario, del relato del funeral de Augusto en el biógrafo Suetonio ("Aug."100) y en el historiador Tácito ("Ann."1.8-10). En primer lugar se remarca la importancia política y social del "funus publicum" en Roma, objeto del relato. Sigue un detenido y minucioso análisis en el que se trata de poner de relieve las semejanzas y, sobre todo, las diferencias entre el relato de Suetonio y el de Tácito en cuanto a los datos aportados, la secuenciación de los mismos y, especialmente, en cuanto a la focalización que sobre ellos y sobre el conjunto del relato muestran uno y otro autor. Finalmente se trata de explicar las diferencias, importantes, entre ambos relatos en virtud del género literario (biografía-historia), de la intención y propósito concretos de cada una de las dos obras ("Vita Augusti" de Suetonio y "Annales" de Tácito) y de la distinta personalidad intelectual de cada uno de los dos autores.