[Role of basolateral amygdaloid nuclei in sleep and wakeful state regulation]

The role of basolateral amygdaloid nuclei (BLN) in sleep and wakeful state (W) was investigated with polysomnography. Electrical lesion of bilateral BLN increased slow wave sleep (SWS) and paradoxical sleep (PS), but decreased W. Bilateral injection of kainic acid (KA), which selectively destroyed the soma of neurons, resulted in biphasic effects. At d 1 after KA, insomnia occurred. At d 4, SWS increased while W decreased, but PS did not change. Unilateral injection of NO donor sodium nitroferricyanide (SNP) caused an enhancement of W and a decrease of SWS. Injection of nitric oxide synthase inhibitor N-nitro-L-arginine (L-NNA) led to opposite effects. L-arginine, a precursor of NO, had no direct effect on sleep and W, but blocked the effects of L-NNA. The results suggest that BLN plays an important role in regulating sleep and wakeful state. Destruction of BLN increases SWS, and NO in BLN has W-promoting and SWS-inhibiting effects, which may be mediated by activation of neurons in BLN.