Association between Chronic Mental Stress and Academic Performance among Korean Adolescents / Asociación entre estrés mental crónico y desempeño académico en adolescentes koreanos

En este estudio se examinó si el estrés mental crónico se asocia con el rendimiento académico en adolescentes coreanos. La muestra estuvo constituida por los 74.186 adolescentes de entre el 7 y el 12 ° grado (12-18 años) que participaron en la 8va encuesta en internet sobre Comportamiento de Riesgo en Jóvenes en 2012. Se utilizó el análisis de regresión logística multivariante para aclarar cómo el estrés crónico mental se relacionaba con el rendimiento académico después del ajuste por edad, índice de masa corporal, posición económica de la familia, el nivel de educación de los padres, la frecuencia de fumar, la frecuencia de ingesta de alcohol, y la frecuencia de la actividad física vigorosa y moderada y ejercicios de fuerza musculares. Para los varones, las personas con estrés mental crónico muy alto tenían menos probabilidades de lograr un rendimiento académico promedio o superior (odds ratio [OR] = 0.738, 95% intervalo de confianza [IC]: 0.629 a 0.867, p <0,001) que aquellos con muy estrés mental baja. Para las niñas, las que tenían estrés mental muy alto tenían menos probabilidades (OR = 0.668; IC del 95%: 0.521 - 0.857, p = 0.002), mientras que aquellas con estrés mental bajo tenían más probabilidades (OR IC = 1.324, 95%: 1.029 -1.704; p = 0.029) para tener un rendimiento promedio académico o superior, en comparación con las niñas con estrés muy bajo. Los grados (pruebas, exámenes de ingreso) fueron la principal causa de estrés mental crónico tanto en varones (51.7%) y niñas (54.,8%). Los varones y las niñas de la República de Corea de estrés mental crónico muy alto mostraron una disminución del rendimiento académico.

We examined whether chronic mental stress is associated with academic performance in Korean adolescents. Our sample consisted of the 74,186 adolescents between the 7th and 12th grades (aged 12-18 years) who participated in the 8th Korean Youth Risk Behavior Web-based Survey in 2012. We used multivariate logistic regression analysis to clarify how chronic mental stress was related to academic performance after adjustment for age, body mass index, family economic status, parents' education level, smoking frequency, alcohol intake frequency, and frequency of vigorous and moderate physical activity and muscular strength exercises. For boys, those with very high chronic mental stress were less likely to achieve average academic performance or higher (odds ratio [OR] = 0.738, 95% confidence interval [CI]: 0.629-0.867, p < 0.001) than were those with very low mental stress. For girls, those with very high mental stress were less likely (OR = 0.668, 95% CI: 0.521-0.857, p = 0.002), while those with low mental stress were more likely (OR = 1.324, 95% CI: 1.029-1.704; p = 0.029) to have average academic performance or hig-her, compared with girls with very low stress. Grades (tests, entrance examinations) were the primary cause of chronic mental stress in both boys (51.7%) and girls (54.8%). Republic of Korean boys and girls with very high chronic mental stress showed decreased academic performance.

Serotonin contracts the rat mesenteric artery by inhibiting 4-aminopyridine-sensitive Kv channels via the 5-HT2A receptor and Src tyrosine kinase

Serotonin (5-hydroxytryptamine (5-HT)) is a neurotransmitter that regulates a variety of functions in the nervous, gastrointestinal and cardiovascular systems. Despite such importance, 5-HT signaling pathways are not entirely clear. We demonstrated previously that 4-aminopyridine (4-AP)-sensitive voltage-gated K+ (Kv) channels determine the resting membrane potential of arterial smooth muscle cells and that the Kv channels are inhibited by 5-HT, which depolarizes the membranes. Therefore, we hypothesized that 5-HT contracts arteries by inhibiting Kv channels. Here we studied 5-HT signaling and the detailed role of Kv currents in rat mesenteric arteries using patch-clamp and isometric tension measurements. Our data showed that inhibiting 4-AP-sensitive Kv channels contracted arterial rings, whereas inhibiting Ca2+-activated K+, inward rectifier K+ and ATP-sensitive K+ channels had little effect on arterial contraction, indicating a central role of Kv channels in the regulation of resting arterial tone. 5-HT-induced arterial contraction decreased significantly in the presence of high KCl or the voltage-gated Ca2+ channel (VGCC) inhibitor nifedipine, indicating that membrane depolarization and the consequent activation of VGCCs mediate the 5-HT-induced vasoconstriction. The effects of 5-HT on Kv currents and arterial contraction were markedly prevented by the 5-HT2A receptor antagonists ketanserin and spiperone. Consistently, alpha-methyl 5-HT, a 5-HT2 receptor agonist, mimicked the 5-HT action on Kv channels. Pretreatment with a Src tyrosine kinase inhibitor, 4-amino-5-(4-chlorophenyl)-7-(t-butyl)pyrazolo[3,4-d]pyrimidine, prevented both the 5-HT-mediated vasoconstriction and Kv current inhibition. Our data suggest that 4-AP-sensitive Kv channels are the primary regulator of the resting tone in rat mesenteric arteries. 5-HT constricts the arteries by inhibiting Kv channels via the 5-HT2A receptor and Src tyrosine kinase pathway.