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Caffeine links dopamine and serotonin release during passive heat loading

Tae-Wook Kim1*, Jeong-Beom Lee2, Hyung-Seok Seo3, Young-Ki Min2 and Hun-Mo Yang2
  • 1 Soonchunhyang University, Health Care, Republic of Korea
  • 2 Soonchunhyang University, Physiolog, Republic of Korea
  • 3 Konyang, Seo, Republic of Korea

The aim of this study was to investigate the serum serotonin (5-HT), prolactin (PRL) and plasma dopamine (DA) levels in humans with and without caffeine ingestion during and after passive heat loading (half immersion in 42°C hot water). Eleven male volunteers participated in the randomized experiment (CON, n=15, 200 mL of tap water vs. CAFF, n=15, 3 mg•kg-1 and 200 mL tap water). After 60 min, passive heat loading was conducted for 30 min. Blood samples were collected and assessed for 5-HT, DA and PRL with and without caffeine during and after passive heat loading. 5-HT was significantly lower in the CAFF group compared to the CON group after passive heat loading for 30 min (Post) (p < 0.05) and also after 60 min of resting (p < 0.01). DA and PRL were significantly higher in the CAFF group than in the CON group at the Post time point (p < 0.001). In conclusion, 3 mg•kg-1 caffeine ingestion prior to passive heat loading can alter central serotonergic and dopaminergic activity, which may contribute to reduced central fatigue and subsequently, to reduced general fatigue. Prolactin responses during passive heat loading were also significantly related to caffeine ingestion in this study. However, the inhibitory effects of DA on PRL by caffeine remain to be elucidated.

Acknowledgements

of the authors have any conflicts of financial interest to declare.

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Keywords: Caffeine, Dopamine, Passvie heat loading, Prolactin, Serotonin

Conference: Neuroinformatics 2015, Cairns, Australia, 20 Aug - 22 Aug, 2015.

Presentation Type: Poster, not to be considered for oral presentation

Topic: Clinical neuroscience

Citation: Kim T, Lee J, Seo H, Min Y and Yang H (2015). Caffeine links dopamine and serotonin release during passive heat loading. Front. Neurosci. Conference Abstract: Neuroinformatics 2015. doi: 10.3389/conf.fnins.2015.91.00040

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Received: 01 Mar 2015; Published Online: 05 Aug 2015.

* Correspondence: Prof. Tae-Wook Kim, Soonchunhyang University, Health Care, Asan, 336-745, 336-745, Republic of Korea, kimtw@sch.ac.kr