TY - JOUR
T1 - Endogenous ouabain-like compounds in locus coeruleus modulate rapid eye movement sleep in rats
AU - Jaiswal, Manoj K.
AU - Dvela, Moran
AU - Lichtstein, David
AU - Mallick, Birendra N.
PY - 2010/3
Y1 - 2010/3
N2 - Summary Although the detailed mechanism of spontaneous generation and regulation of rapid eye movement sleep (REMS) is yet unknown, it has been reported that noradrenergic REM-OFF neurons in the locus coeruleus (LC) cease firing during REMS and, if they are kept active, REMS is significantly reduced. On the other hand, the activity as well as expression of Na-K ATPase has been shown to increase in the LC following REMS deprivation. Ouabain is a specific inhibitor of Na-K ATPase, and endogenous ouabain-like compounds are present in the brain. These findings led us to propose that a decrease in the level of ouabain-like compounds spontaneously available in and around the LC would stimulate and increase the REM-OFF neuronal activities in this region and thus would reduce REMS. To test this hypothesis, we generated anti-ouabain antibodies and then microinjected it bilaterally into the LC in freely moving chronically prepared rats and recorded electrophysiological signals for evaluation of sleep-wakefulness states; suitable control experiments were also conducted. Injection of anti-ouabain antibodies into the LC, but not into adjacent brain areas, significantly reduced percent REMS (mean ± SEM) from 7.12 (±0.74) to 3.63 (±0.65). The decrease in REMS was due to reduction in the mean frequency of REMS episode, which is likely due to increased excitation of the LC REM-OFF neurons. Control microinjections of normal IgG did not elicit this effect. These results support our hypothesis that interactions of naturally available endogenous ouabain-like compounds with the Na-K ATPase in the LC modulate spontaneous REMS.
AB - Summary Although the detailed mechanism of spontaneous generation and regulation of rapid eye movement sleep (REMS) is yet unknown, it has been reported that noradrenergic REM-OFF neurons in the locus coeruleus (LC) cease firing during REMS and, if they are kept active, REMS is significantly reduced. On the other hand, the activity as well as expression of Na-K ATPase has been shown to increase in the LC following REMS deprivation. Ouabain is a specific inhibitor of Na-K ATPase, and endogenous ouabain-like compounds are present in the brain. These findings led us to propose that a decrease in the level of ouabain-like compounds spontaneously available in and around the LC would stimulate and increase the REM-OFF neuronal activities in this region and thus would reduce REMS. To test this hypothesis, we generated anti-ouabain antibodies and then microinjected it bilaterally into the LC in freely moving chronically prepared rats and recorded electrophysiological signals for evaluation of sleep-wakefulness states; suitable control experiments were also conducted. Injection of anti-ouabain antibodies into the LC, but not into adjacent brain areas, significantly reduced percent REMS (mean ± SEM) from 7.12 (±0.74) to 3.63 (±0.65). The decrease in REMS was due to reduction in the mean frequency of REMS episode, which is likely due to increased excitation of the LC REM-OFF neurons. Control microinjections of normal IgG did not elicit this effect. These results support our hypothesis that interactions of naturally available endogenous ouabain-like compounds with the Na-K ATPase in the LC modulate spontaneous REMS.
KW - Anti-ouabain antibody
KW - Brain excitability
KW - Microinjection
KW - Na-K ATPase
KW - REM sleep
UR - http://www.scopus.com/inward/record.url?scp=77950661897&partnerID=8YFLogxK
U2 - 10.1111/j.1365-2869.2009.00781.x
DO - 10.1111/j.1365-2869.2009.00781.x
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C2 - 19878449
AN - SCOPUS:77950661897
SN - 0962-1105
VL - 19
SP - 183
EP - 191
JO - Journal of Sleep Research
JF - Journal of Sleep Research
IS - 1 PART. 2
ER -