Role Of Dorsal Raphe Nucleus In The Regulati On Of Deep Slow Wave Sleep

The role and mechanism of serotonin (5-HT) in dorsal raphe nuclei (DRN) and basolateral amygdaloid nuclei (BLA) on sleep were investigated with polysomnography, steotaxic, surgery, lesions of nuclei, microinjection, immunohistochemical method and electrophsiologic technique. Results as follows: 1 The role of serotonergic neurons in DRN on sleep: (1) When kainic acid (KA O.5~gI~.tl) was microinjected into DRN, SWS2 was promoted, W was reduced; (2) Microinjection of L-glutamate (L-Glu O.S~g4il) into DRN decreased SWS2 and REMS, increased W; (3) After microinjection of p-chlorophenylalanine (PCPA lOj.Lg4LI) into DRN depressed synthesize of endogenous 5-HT in DRN, W was enhanced while SWS2 and REMS were reduced, (4) After microinjection of PCPA (1O~g4tI) into DRN, the results of immuno- histochemistry showed that serotonin-positive neurons in DRN were decreased compared with control group. 2. The effect of serotonergic nerve fiber of BLA from DRN on sleep: (1) When L-Glu was microinjected into DRN, MS which is the non-selective 5-HT antiagonist was microinjected bilateral BLA. We found that SWS2 and R.EMS of rats was not changed. (2) Microinjection of 5-HTP which can convert to 5-FIT by the enzyme tryptophane hydroxylase and enhance 5-HI into bilateral BLA could block the effect of microinjection of PCPA into DRN on sleep. 3. The electrophsiologic characters of normal neurons of BLA: (1) The current of Na~~ K~ and Ca2~ of normal neurons in BLA 3 (2) The current of glycine and GABA of normal neurons in BLA. The results showed that (1) Excitation of cell bodies of neurons in DRN reduced SWS2 and REMS, increased W;however destruction of cell bodies of neurons in DRN or blocking synthesize of endogenous serotonin in DR.N had revers roles: enhanced SWS2 and REMS, decreased W. This suggested that DRN was an important nucleus in regulation of sleep and this mechanism was mediated by serotonin.(2) Blocking the receptoe of serotonin in BLA could prevent the effect of L-Glu in DRN on sleep, while enhancement of 5-HTP in BLA could prohibit the role of microinjection of PCPA into DRN on sleep. This showed that it was through serotonergic nerve fiber into BLA that DRN regulated sleep.