| Budget Amount *help |
¥2,200,000 (Direct Cost: ¥2,200,000)
Fiscal Year 1988: ¥400,000 (Direct Cost: ¥400,000)
Fiscal Year 1987: ¥400,000 (Direct Cost: ¥400,000)
Fiscal Year 1986: ¥1,400,000 (Direct Cost: ¥1,400,000)
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| Research Abstract |
To investigate the effect of extrinsic MHBAA (1-methy1 hepty1-gamma-bromoaceto-acetate) on the feline sleep-wakefulness cycle, especially on REM sleep, 10 adult male cats, each weighing 3 to 5 Kg, were implanted with recording electrodes and microinjection guide tubes. All animals were kept in individual cages under an automated daily light-dark cycle (12:12), with lights on from 06:00 to 18:00; food and water were freely available before surgery and the animals were exposed to the same conditions throughout the course of this experiment.
Before microinjection of MHBAA into the dorsal pontine tegmentum region, the administration site was confirmed using neostigmine bromide to obtain enhanced desynchronized sleep signs. After the adminstration of 250 nl of saline and 200 nl (683 nmol) of MHBAA, behavior and brain activities were monitored for more than 24 hours by polysomnography. The animals were divided into 2 groups, according to the time of microinjection: the L group, 5 cats, was injected at 10:00, and the D group, 5 cats, was injected at 22:00.
The L group showed a significant increase in REM sleep and a decrease in wakefulness after MHBAA injection, compared to the saline injection. Maximum increase in REM sleep occurred at 6 hours after injection. The D group, however, showed no overall effects on either REM sleep or wakefulness during the 24-hour period, although REM sleep significantly increased 5 hours after MHBAA injection and did decrease 21 hours after injection, compared to the saline injection.
Considering our previous investigations of intrinsic MHBAA levels in the human blood and in the cat CSF and blood, extrinsic MHBAA, which shows an anticholinesterase action in vitro, clearly enhanced REM sleep, affecting the intrinsic MHBAA level in vivo.
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