• Bulletin of the Korean Chemical Society
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• 제28권2호
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• pp.276-280
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• 2007

In this work, caffeine and some catechin compounds + C, EC, EGC, and EGCG were extracted from green tea by using molecular imprinted polymers (MIP) as sorbent materials in a solid-phase extraction (SPE) process known as MISPE (molecular imprinted solid-phase extraction). For synthesis of MIP, caffeine was employed as the template, MAA as the monomer, EGDMA as the crosslinker, and AIBN as the initiator. A solution of caffeine (0.2 mg/mL in methanol) was utilized in the solid extraction cartridges following loading, washing, and elution procedures with acetonitrile, methanol, and methanol-acetic acid (90/10, %v/v) as the solvents, respectively. This solid-phase extraction protocol was applied for the extraction of caffeine and some catechin compounds from green tea. A comparison was made between the results obtained with the MIP cartridges and a traditional C18 reversed-phase cartridge. It was thereupon found that the recovery of caffeine by the MIPbased sorbent used in this work was almost two and four times greater than that by a commercially available C18 material. A quantitative analysis was conducted by high performance liquid chromatography (HPLC) using a C18 column (5 μm, 250 × 4.6 mm) with methanol/water (40/60, %v/v) as the mobile phase at a flow rate of 0.5 mL/min.

• Archives of Pharmacal Research
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• 제14권1호
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• pp.55-67
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• 1991

The influence of caffeine on secretion of catecholamines (CA) was examined in the isolated perfused rat adrenal gland. Caffeine (0.3 mM) perfused into an adrenal vein of the gland produced a marked increase in secretion of CA. This secretory effect of CA evoked by perfusion of caffeine for one minute was considerably prolonged, lasting for more than 90 minutes. The tachyphylaxis to releasing effect of CA induced by caffeine was observed by repeated perfusion of this drug. The caffeine-evoked CA secretion was markedly inhibited by pretreatment with ouabain, trifluoperazine, TMB-8 and perfusion with calcium-free Krebs solution containing 5 mM EGTA, but was not affected by perfusion of calcium-free Krebs solution without other addition. CA secretion evoked by caffeine was not reduced significantly by pretreatment with chlorisondamine but after the first collection of perfusate for 3 min was clearly inhibited. Interestingly, the caffeine-evoked CA secretion was considerably potentiated by pretreatment with atropine or pirenzepine, but after the first collection for 3 min it was markedly decreased. These experimental results suggest that caffeine causes a marked increase in secretion of CA from the isolated perfused rat adrenal gland by an extracellular calcium-independent exocytotic mechanism. The secretory effect of caffeine may be mainly due to mobilization of calcium from an intracellular calcium pool in the rat chromaffin cells and partly due to stimulation of both muscarinic and nicotinic receptors.

• 한국엔터테인먼트산업학회논문지
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• 제14권8호
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• pp.197-202
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• 2020

본 연구에서는 20대 여성의 카페인 중독이 심장호흡기계 능력에 미치는 영향을 조사하였다. 본 연구의 대상자는 G 광역시 소재의 H 대학교 여학생 35명을 카페인 중독자(n=17)과 카페인 비중독자(n=18)가 참여하였다. 심장능력을 평가하기 위해 사이클 에르고미터를 사용하여 최대산소섭취량, 최대에너지소비량, METs를 측정하였으며, 호흡기계 능력은 파워브리드 K5를 사용하여 최대들숨압, 평균들숨압, 최대들숨유속, 평균들숨유속, 최대들숨량, 평균들숨량을 측정하였다. 본 연구의 결과는 심장능력에서 카페인 중독군은 카페인 비중독군에 비해 최대산소섭취량과 METs에서 통계학적으로 유의한 감소를 보였으며, 호흡기계 능력에서는 카페인 중독군이 비중독군에 비해 최대들숨압, 평균들숨압, 최대들숨유속, 평균들숨유속에서 통계학적으로 유의한 감소를 보였다. 본 연구의 결과를 종합하면, 카페인 중독은 20대 여성의 심장호흡기계 능력의 감소를 보였다. 따라서 본 연구의 결과는 20대 여성의 카페인 중독예방을 위한 기초자료로 활용할 수 있을 것이다.

• Fisheries and Aquatic Sciences
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• 제17권1호
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• pp.13-18
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• 2014

Sleep is vital to maintain health and well-being; however, insomnia is currently a widespread health complaint worldwide. In particular, caffeine, a psychoactive component of coffee, tea, and caffeine beverages may lead to sleep disorders such as insomnia. In this study, our primary objective was to investigate the inhibitory effect of high-purity phlorotannin preparation (HP-PRT) on caffeine-induced wakefulness. The sleep test of pentobarbital-induced mice was used as an in vivo animal model. Caffeine (50 and 100 mg/kg) showed significant arousal effects (an increase in sleep latency and a decrease in sleep duration). Co-administration of caffeine (50 mg/kg) and the sedative-hypnotic diazepam (DZP, 1 mg/kg) did not result in similar arousal activity. HP-PRT (500 mg/kg) also inhibited caffeine-induced wakefulness. Our results suggest that HP-PRT would be a useful additive for developing coffee products without the arousal effect.

• 한국수정란이식학회지
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• 제7권2호
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• pp.73-79
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• 1992

Effects of caffeine, heparin and caffeine-heparin treatments for in vitro capacitation of Korean Native Cattle sperm on acrosorne reaction and viability were studied using the methods of Wells-Awa and Dual stain. The results were summerized as follows: 1. The acrosome reaction of sperm when treated with caffeine after 0 to 4 hrs of preincubation were 11.0~75.7% for Wells-Awa stain, and 14.3~75.55% for Dual stain. True acrosome reaction of sperm for Dual stain was 3.0~29.2%. The viability of sperm was 62. 2~27.2%. 2. The acrosome reaction of sperm when treated with heparin after 0 to 4 hrs of preincubation were 17.0~81.2% for Wells-Awa, and 14.3~75.5% for Dual Stain. True acrosome reaction of sperm for Dual stain was 1.5~26.6%. The viability of sperm was 58.6~35. 8%. 3. The acrosome reaction of sperm when treated with caffeine-heparin after 0 to 4 hrs of preincubation were 13.0~83.2% for Wells Awa, and 11.0~78.5% for Dual stain. True acrosome reaction of for Dual stain was 5.1~26.3%. The viability of sperm was 60.5~30.1%.

• Journal of Audiology & Otology
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• 제24권1호
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• pp.10-16
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• 2020

Background and Objectives:The blockage of adenosine receptors by caffeine changes the levels of neurotransmitters. These receptors are present in all parts of the body, including the auditory and vestibular systems. This study aimed to evaluate the effect of caffeine on evoked potentials using auditory brainstem responses (ABRs) and cervical vestibular-evoked myogenic potentials (cVEMPs) in a double-blind placebo-controlled study. Subjects and Methods: Forty individuals (20 females and 20 males; aged 18-25 years) were randomly assigned to two groups: the test group (consuming 3 mg/kg pure caffeine powder with little sugar and dry milk in 100 mL of water), and the placebo group (consuming only sugar and dry milk in 100 mL water as placebo). The cVEMPs and ABRs were recorded before and after caffeine or placebo intake. Results: A significant difference was observed in the absolute latencies of I and III (p<0.010), and V (p<0.001) and in the inter-peak latencies of III-V and I-V (p<0.001) of ABRs wave. In contrast, no significant difference was found in cVEMP parameters (P13 and N23 latency, threshold, P13-N23 amplitude, and amplitude ratio). The mean amplitudes of P13-N23 showed an increase after caffeine ingestion. However, this was not significant compared with the placebo group (p>0.050). Conclusions: It seems that the extent of caffeine's effects varies for differently evoked potentials. Latency reduction in ABRs indicates that caffeine improves transmission in the central brain auditory pathways. However, different effects of caffeine on auditory- and vestibular-evoked potentials could be attributed to the differences in sensitivities of the ABR and cVEMP tests.

• 대한청각학회지
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• 제24권1호
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• pp.10-16
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• 2020

Background and Objectives:The blockage of adenosine receptors by caffeine changes the levels of neurotransmitters. These receptors are present in all parts of the body, including the auditory and vestibular systems. This study aimed to evaluate the effect of caffeine on evoked potentials using auditory brainstem responses (ABRs) and cervical vestibular-evoked myogenic potentials (cVEMPs) in a double-blind placebo-controlled study. Subjects and Methods: Forty individuals (20 females and 20 males; aged 18-25 years) were randomly assigned to two groups: the test group (consuming 3 mg/kg pure caffeine powder with little sugar and dry milk in 100 mL of water), and the placebo group (consuming only sugar and dry milk in 100 mL water as placebo). The cVEMPs and ABRs were recorded before and after caffeine or placebo intake. Results: A significant difference was observed in the absolute latencies of I and III (p<0.010), and V (p<0.001) and in the inter-peak latencies of III-V and I-V (p<0.001) of ABRs wave. In contrast, no significant difference was found in cVEMP parameters (P13 and N23 latency, threshold, P13-N23 amplitude, and amplitude ratio). The mean amplitudes of P13-N23 showed an increase after caffeine ingestion. However, this was not significant compared with the placebo group (p>0.050). Conclusions: It seems that the extent of caffeine's effects varies for differently evoked potentials. Latency reduction in ABRs indicates that caffeine improves transmission in the central brain auditory pathways. However, different effects of caffeine on auditory- and vestibular-evoked potentials could be attributed to the differences in sensitivities of the ABR and cVEMP tests.

• Investigative Magnetic Resonance Imaging
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• 제21권4호
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• pp.199-209
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• 2017

Purpose: Caffeine is the most widely consumed psychostimulant. It is often adopted as a tool to modulate brain activations in fMRI studies. However, its pharmaceutical effect on task-induced deactivation has not been fully examined in fMRI. Therefore, the purpose of this study was to examine the effect of caffeine on both activation and deactivation under sustained attention. Materials and Methods: Task fMRI was acquired from 26 caffeine naive healthy volunteers before and after taking caffeine pill (200 mg). Results: Statistical analysis showed an increase in cognition-load dependent task activation but a decrease in load dependent de-activation after caffeine ingestion. Increase of attention and memory task activation and its load-dependence suggest a beneficial effect of caffeine on the brain even though it has no overt behavior improvement. The reduction of deactivation by caffeine and its load-dependence indicate reduced facilitation from task-negative networks. Conclusion: Caffeine affects brain activity in a load-dependent manner accompanied by a disassociation between task-positive network and task-negative network.

• 생명과학회지
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• 제11권1호
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• pp.1-7
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• 2001

The caffeine intake cause a local or wide ranges of convulsion and it is associated with release of dopamine (DA) receptors into the brain striatum. However, the effect of caffeine addiction on expression of DA receptors gene in the rat caudate-putamen (CPu), nucleus accumbens (NAc), and olfactory tubercle (OTu) has not been elucidated. In this study, we examined the influence of caffeine addiction on DA D $_1$and D$_2$receptor mRNAs after the treatment of caffeine for four weeks. Using the specific antisense ribo-probes for DA D$_1$and D$_2$receptor cDNAs, in situ hybridization was performed on the CPu, NAc, and OTu of the adult male Sprague Dawely rats. In caffeine-treated group, DA D$_1$and D$_2$receptor mRNAs were highly increased in CPu, NAc, and OTu. The expression density of DA D$_1$receptor mRNAs were 2.52${\pm}$1.40 (CPu), 2.78${\pm}$1.69 (NAc), and 3.91${\pm}$1.28 (OTu) in control group and 7.76${\pm}$2.09 (CPu), 4.2 ${\pm}$1.85 (NAc), and 8.21${\pm}$1.72 (OTu) in caffeine-treated group. The expression density of DA D$_2$receptor mRNA was 2.32${\pm}$1.52 (CPu), 2.63${\pm}$2.11 (NAc), and 3.61${\pm}$1.43 (OTu) in control group, and 6.41${\pm}$1.82 (CPu), 6.89${\pm}$1.32 (NAc), and 6.82${\pm}$1.18 (OTu) in caffeine-treated group. DA D$_1$receptor mRNA was higher expressed than DA D$_2$ receptor mRNA in CPu and NAc. These results suggest that caffeine reacts as a upregulator of the expression of DA D$_1$and D$_2$receptor mRNA among the neurotransmitters.

• 생명과학회지
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• 제12권4호
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• pp.375-382
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• 2002

운동이 수면에 미치는 효과를 보다 명확하게 검증하기 위해 일반상태가 아닌 카페인으로 인한 수면장애 상태에서 운동의 효과를 조사하였다. 본 연구의 피험자는 3회의 실험 조건(1. 평상시, 2. 카페인 섭취, 3. 카페인섭취 $\times$운동)에 참여해서 이들의 수면변수와 수면시 뇌파를 측정하였다. 카페인은 고용량으로 1200mg(400mg$\times$3)을 투여하였으며, 운동강도는 60% V $O_{2peak}$에서 60분을 사이클 에르고미터를 이용해 실시하였다. 본 실험결과 카페인 섭취로 입면시간 연장과 수면효율성 감소 그리고 서파수면(SWS)의 감소로 수면에 불리한 효과를 유발시켰다. 하지만 카페인 섭취와 운동을 병행했을 때 카페인 투여시 발생된 효과를 상쇄시키는 효과가 나타났다. 이러한 결과로써 고용량의 카페인 섭취가 수면장애 유발 효과가 있었지만 운동을 병행해서 실시했을 때 수면촉진과 수면효율성 그리고 숙면인 서파수면의 증가가 나타남으로써 운동이 수면방해를 완화시키고 수면 향상에 효과가 있는 것으로 생각된다.