Monoaminergic influences on the cholinergic waking active neurons in the mesopontine tegmentum

s220

455

THE ROLE OF MATERNAL MELATONIN

HITOKI OHTSUKA,YOSHIAKI

MIYAKEJCHIRO

IN THE ENTRAINME NT OF FETAL CIRCADIAN

MURAI’,KAzUO

RHYTHMS

SATOH ’

KATSUJ3IKO SAKAMOTO,NORIO ISHIDA2 ’Dept.&f Obstetrics and Gynecology,Nihon Univ.School

of Med. ’National Institute of Bioscience and Human Technology,MITI,Tukuba ’Dept.of Biochemistry,Nihon Univ. School of Med.

0bjective)Maternal melatonin is an important hormone to transport information about photopeiod during fetal developement. we examined the role of melatonin in matemo-fetal enmiinment. Method)All pregnant Wistar rats were pinealectomized at gestational day 7 and the effect of pinealectomy on the melatonin binding sites in suprachiasmatic nucleus(SCN) and the serotonin-N-acethyl transferase(NAT) mRNA in Retina were examined througtlr the fetal(EDl8-2 1) and postnatal period(PD3-30). Simultaneously ,the serum levels of melatonin were measured at day(cT6) and night(CT18) in each peirod. Results)The melatonin binding sites were increased after delivery and reached to maternal level at PD7 ,when the serum level of melatonin begin to incraese and the diurnal variation also appeared.The melatonin binding sites in fetal SCN were upregulated at ED2 1 -PD3 , and diurnal rhythm of the serotonin-NAT mRNA in retina were disappeared by maternal pinelectomy. Conclusion)The maternal derived melatonin may affect the entrainment of circadian rhythms during fetal developement. CHOLINE

456 YAEKO

NUCLEUS NINOMIYA

Dept. of Physiol., Chohnergic paradoxical

ACETYLTRANSFERASE

ACTIVITY

OF THE DEVELOPING AND YOSHIMASA

Fat. of Medicine,

RAT.

Medical College,

tegmental

sleep or waking and acetylcholine

neonatal rats and it decreases

TEGMENTAL

KOYAMA

Fukushima

neurons in the laterodorsal

IN THE LATERODORSAL

nucleus(LDT)

Hikarigaoka,

Fukushima

960-1295

have an important role inthe regulation

may trigger this sleep. The amount of paradoxical

as they get older.

To clarify the relation between the development

of

sleep is higher in of cholinergic

nature

of the LDT neurons and the change of sleep pattern from neonatal to adult, we measured the activity of choline acetyhransferase(ChAT), immunohistochemically

a synthetic enzyme for acetylcholine, from postnatal day 1 to adult.

in the LDT of rats biochemically

and

In the first postnatal week, ChAT activity in the LDT was less

than 10% of that in adult rats. In the second postnatal week, the activity increased rapidly and in the third postnatal week, it reached to the same level as that in adult rats. The activity was maintained results suggest that cholinergic enough amount of acetylcholine

MESOPONTINE

YOSHIMASA

Department

KOYAMA,

of Physiology,

to adulthood.

These produce

after 3 weeks of birth.

MONOAMINERGIC

457

thereafter

neurons in the LDT are immature in early postnatal period and consistently

INFLUENCES

ON THE CHOLINERGIC

WAKING ACTIVE

NEURONS

IN THE

TEGMENTUM.

YUKIHIKO

Fukushima

KAYAMA

Medical University,

The cholinergic neurons in the laterodorsal sleep (PS) or waking. A group of neurons

tegmental

School of Medicine,

Fukushima

960-1295

nucleus (LDT) have a crucial role in the regulation

in this area are specifically

active during PS and virtually

of paradoxical

silent during waking

(PS-on neurons),

while another one are active both during PS and waking

(Type I-S or WP neurons).

these cholinergic

neurons are interacted

neurons, all of which are active during waking

and silent during PS (PS-off neurons). the monoaminergic unanesthetized,

(NA) and serotonin

rats. The cholinergic

of the Type I-S neurons so far examined by non-noradrenergic

or serotonergic

It is proposed

To know how the activity of Type I-S (WP) neurons during waking are regulated

neurons, noradrenaline

head-restrained

may be maintained

with noradrenergic

(5HT) were applied iontophoretically

nature of the neurons was postulated

that

by

to the LDT neurons of

by width of action potentials.

All

were inhibited by NA and 5HT. In rats, activity of Type I-S neurons during waking and non-serotonergic

neurons