Rapid changes in glutamate levels in the posterior hypothalamus across sleep-wake states in freely behaving rats.
|Title||Rapid changes in glutamate levels in the posterior hypothalamus across sleep-wake states in freely behaving rats.|
|Publication Type||Journal Article|
|Year of Publication||2008|
|Authors||John J, Ramanathan L, Siegel JM|
|Journal||Am J Physiol Regul Integr Comp Physiol|
|Date Published||2008 Dec|
|Keywords||Animals, Biosensing Techniques, Glutamic Acid, Histamine, Hypothalamic Area, Lateral, Hypothalamus, Posterior, Male, Microdialysis, Rats, Rats, Sprague-Dawley, Sleep Deprivation, Sleep, REM, Time Factors, Wakefulness|
The histamine-containing posterior hypothalamic region (PH-TMN) plays a key role in sleep-wake regulation. We investigated rapid changes in glutamate release in the PH-TMN across the sleep-wake cycle with a glutamate biosensor that allows the measurement of glutamate levels at 1- to 4-s resolution. In the PH-TMN, glutamate levels increased in active waking (AW) and rapid eye movement (REM) sleep compared with quiet waking and nonrapid eye movement (NREM) sleep. There was a rapid (0.6 +/- 1.8 s) and progressive increase in glutamate levels at REM sleep onset. A reduction in glutamate levels consistently preceded the offset of REM sleep by 8 +/- 3 s. Short-duration sleep deprivation resulted in a progressive increase in glutamate levels in the PH-TMN, perifornical-lateral hypothalamus (PF-LH), and cortex. We found that in the PF-LH, glutamate levels took a longer time to return to basal values compared with the time it took for glutamate levels to increase to peak values during AW onset. This is in contrast to other regions we studied in which the return to baseline values after AW was quicker than their rise with waking onset. In summary, we demonstrated an increase in glutamate levels in the PH-TMN with REM/AW onset and a drop in glutamate levels before the offset of REM. High temporal resolution measurement of glutamate levels reveals dynamic changes in release linked to the initiation and termination of REM sleep.
|Alternate Journal||Am. J. Physiol. Regul. Integr. Comp. Physiol.|
|PubMed Central ID||PMC2685298|
|Grant List||HL-41370 / HL / NHLBI NIH HHS / United States |
MH-64109 / MH / NIMH NIH HHS / United States