Forskning

January 4, 2012

Caffeine-induced synaptic potentiation in hippocampal CA2 neurons

S B Simons et al,  Caffeine-induced synaptic potentiation in hippocampal CA2 neurons, Nature Neuroscience, 2012, Volume 15, Number 1.

Caffeine enhances cognition, but even high non-physiological doses have modest effects on synapses. A1 adenosine receptors (A1Rs) are antagonized by caffeine and are most highly enriched in hippocampal CA2, which has not been studied in this context. We found that physiological doses of caffeine in vivo or A1R antagonists in vitro induced robust, long-lasting potentiation of synaptic transmission in rat CA2 without affecting other regions of the hippocampus.

Adenosine in the brain is thought to rise throughout the day and to be cleared during sleep2. Our results support the hypothesis that the use of caffeine provides temporary increases in mental acuity by blocking the normal inhibitory effects of adenosine. The role of CA2 in brain function is unknown, but clues may be gleaned by the finding that the number of nonpyramidal (inhibitory) neurons is reduced in the CA2 of individuals with schizophrenia and that caffeine has been observed to worsen symptoms of psychosis. Notably, knockout of a vasopressin receptor enriched in CA2 produces mice with impairments in social recognition memory and caffeine enhances this kind of memory in rodents. Thus, the robust potentiation induced by caffeine exposure both in vivo and in vitro strongly suggests that A1R-P in CA2 is the physiological substrate for the cognitive enhancement provided by caffeine consumption.