The Durk Pearson & Sandy Shaw®
Life Extension NewsTM
Volume 13 No.
1 • February 2010
A vulture boards an airplane, carrying two dead raccoons. The stewardess looks at him and says, “I’m sorry, sir, only one carrion allowed per passenger.”
A woman has twins and gives them up for adoption. One of them goes to a family in Egypt and is named “Ahmal.” The other goes to a family in Spain, they name him “Juan.” Years later, Juan sends a picture of himself to his birth mother. Upon receiving the picture, she tells her husband that she wishes she also had a picture of Ahmal. Her husband responds, “They’re twins! If you’ve seen Juan, you’ve seen Ahmal.”
—Patriot Humor, patriotpost.us
Melatonin Preserves Longevity Protein SIRT1
Expression in the Hippocampus and Cognitive
Function of Total Sleep-Deprived Rats
A new neuroprotective effect of melatonin has been reported recently, suggesting that “melatonin may serve as a novel therapeutic strategy directed for preventing the memory deficits resulting from TSD [total sleep deprivation], possibly by effectively preserving the metabolic function and neuronal plasticity engaged in maintaining cognitive activity.” SIRT1 is known to play an important role in maintaining metabolic homestasis and neuronal plasticity.
Adult Wistar rats were prevented from sleeping for five days (!) by a diabolical device that had the rats in a platform above a rectangular tray filled with water to a depth of 5 cm. Rats have an aversion to water. As the authors described it, when sleep onset was detected in the sleep-deprived rat, the device rotated a disc carrying the rat toward the water, which required the rat to both stay awake and to walk against the direction of the disc rotation to avoid being forced into the water.
After five days of this treatment with no sleep, the amount of SIRT1 activity in the hippocampus was drastically decreased. The rats’ performance on the Morris water maze (where the animals have to find a hidden submerged platform that allows them to discontinue swimming without drowning) was also considerably decreased (taking the TSD rats 47 ± 5.62 sec. to find the platform compared to 35 ± 2.51 sec. by the normal not-sleep-deprived rats). A test of memory, in which the submerged platform is removed and the time that rats spend in the area of the former location is determined, showed that the TSD rats spent less percentage of time in the target quadrant (19 ± 0.83% as compared to 38 ± 1.25% by the non sleep-deprived rats).
In TSD rats that were given melatonin treatment, the relative protein levels of SIRT1 in the hippocampus were preserved, with greater effects at higher doses of melatonin. The time to find the submerged platform in the Morris water maze was also decreased by melatonin treatment in the TSD rats. In the rats receiving 100 mg/kg of melatonin, time to find the hidden platform was 36 ± 2.50 sec. as compared to the 47 ± 5.62 sec. for the TSD rats not receiving melatonin. When the hidden platform was removed, rats given 5 mg/kg of melatonin spent much more time in the target quadrant (31 ± 2.08 sec.) as compared to the untreated TSD rats (19 ± 0.83 sec.).
Isn’t it nice to know that the next time you plan (or not) to get no sleep for five days, you can (assuming it works similarly as in the rats) prevent much of the cognitive impairment that would otherwise occur?
- Chang et al. Melatonin preserves longevity protein (sirtuin 1) expression in the hippocampus of total sleep-deprived rats. J Pineal Res 47:211-20 (2009).