BackgroundIn various studies in adults, caffeine may increase wakefulness and relieve pain, but caffeine overdose can cause many adverse serious effects on health. Caffeine intake has recently been increasing in adolescents. In spite of importance of caffeine effects on Korean adolescents, there are lack of scientific and systematic studies. The purpose of our study was to identify the relationship between caffeine consumption and effects on adolescents.MethodsWe performed study on 234 middle school students at one middle school in Daegu using a self-report questionnaire. We divided students to quartiles according to amount of caffeine intake. We used Beck Depression Inventory (BDI) to evaluate the degree of depression and Beck Anxiety Inventory (BAI) to evaluate the degree of anxiety. We also used Insomnia Severity Scale (ISI) to evaluate the degree of insomnia and Global Assessment of Recent Stress (GARS) to evaluate the stress in students. We used logistic regression analysis to identify the relationship between caffeine consumption and effects.ResultsHigher caffeine intake was associated with higher weight, height, lower academic achievement, and higher score in BDI, BAI, ISI, and GARS (P for trend <0.005). Higher caffeine intake quartile was associated with greater odds of having significant depression (BDI ≥10, P for trend=0.011), and insomnia (ISI ≥8, P for trend=0.015) after adjustment for factors that can affect the psychological status.ConclusionWe found that caffeine intake is associated weight, height, academic achievement, and higher score in BDI, BAI, ISI, and GARS. Caffeine intake was positively associated with the severity of depression and the severity of insomnia among adolescents in Korean.

The subunit composition of the AMPA receptor is critical to its function. AMPA receptors that display very low calcium permeability include the GluR2 subunit, while AMPA receptors that contain other subunits, such as GluR1, display high calcium permeability. We have studied the distribution and morphology of neurons containing GluR1 in the hamster visual cortex with antibody immunocytochemistry. We compared this labeling to that for calbindin D28K, parvalbumin, and GABA. Anti-GluR1-immunoreactive (IR) neurons were located in all layers. The highest density of GluR1-IR neurons was found in layers II/III. The labeled neurons were non-pyramidal neurons, but were varied in morphology. The majority of the labeled neurons were round or oval cells. However, stellate, vertical fusiform, pyriform, and horizontal neurons were also labeled with the anti-GluR1 antibody. Two-color immunofluorescence revealed that many of the GluR1-IR neurons in the hamster visual cortex were double-labeled with either calbindin D28K (31.50%), or parvalbumin (22.91%), or GABA (63.89%). These results indicate that neurons in the hamster visual cortex express GluR1 differently according to different layers and selective cell types, and that many of the GluR1-IR neurons are limited to neurons that express calbindin D28K, parvalbumin, or GABA. The present study elucidates the neurochemical structure of GluR1, a useful clue in understanding the differential vulnerability of GluR1-containing neurons with regard to calcium-dependent excitotoxic mechanisms.

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