A nasal spray made with the immune molecule interleukin-6 was found to improve certain kinds of memory after a good night's sleep.
Article from ScienceDaily.com:
Scientists Develop Nasal Spray That Improves Memory
ScienceDaily (Oct. 1, 2009) — Good news for procrastinating students: a nasal spray developed by a team of German scientists promises to give late night cram sessions a major boost, if a good night's sleep follows. In a research report featured as the cover story of the October 2009 print issue of The FASEB Journal, these scientists show that a molecule from the body's immune system (interleukin-6) when administered through the nose helps the brain retain emotional and procedural memories during REM sleep.
"Sleep to remember, a dream or reality?" said Lisa Marshall, co-author of the study, from the Department of Neuroendocrinology at the University of Lubeck in Germany. "Here, we provide the first evidence that the immunoregulatory signal interleukin-6 plays a beneficial role in sleep-dependent formation of long-term memory in humans."
To make this discovery, Marshall and colleagues had 17 healthy young men spend two nights in the laboratory. On each night after reading either an emotional or neutral short story, they sprayed a fluid into their nostrils which contained either interleukin-6 or a placebo fluid. The subsequent sleep and brain electric activity was monitored throughout the night. The next morning subjects wrote down as many words as they could remember from each of the two stories. Those who received the dose of IL-6 could remember more words.
"If a nasal spray can improve memory, perhaps we're on our way to giving some folks a whiff of common sense, such as accepting the realities of evolution," said Gerald Weissmann, M.D., Editor-in-Chief of The FASEB Journal. "This is exciting piece of interdisciplinary science, since IL-6 had previously been considered a by-product of inflammation
Study abstract:
Enhancing influence of intranasal interleukin-6 on slow-wave activity and memory consolidation during sleep
The cytokine IL-6 has been considered to exert neuromodulating influences on the brain, with promoting influences on sleep. Sleep enhances the consolidation of memories, and, in particular, late nocturnal sleep also represents a period of enhanced IL-6 signaling, due to a distinctly enhanced availability of soluble IL-6 receptors during this period, enabling trans-signaling of IL-6 to neurons. Thus, a contribution of IL-6 to sleep-dependent memory consolidation is hypothesized. To test this hypothesis, we compared effects of intranasally administered IL-6 (vs. placebo) on sleep-dependent consolidation of declarative (neutral and emotional texts, 2-dimensional object location) and procedural (finger sequence tapping) memories in 17 healthy young men. IL-6 distinctly improved the sleep-related consolidation of emotional text material (P<0.03), which benefits mostly from sleep in the second night-half, in which rapid eye movement sleep (REM) dominates the non-REM-REM sleep cycle. During this second night-half, the amount of electroencephalogram slow-wave activity (0.5–4 Hz) distinctly increased after IL-6 (P<0.01). Other types of memory were not affected. The ability of IL-6 to enhance sleep-associated emotional memory consolidation highlights an example of a functional interaction between the central nervous and immune system.—Benedict, C., Scheller, J., Rose-John, S., Born, J., Marshall, L. Enhancing influence of intranasal interleukin-6 on slow-wave activity and memory consolidation during sleep.
