D-aspartate modulates melatonin synthesis in rat pinealocytes.
It has been known that pinealocytes contain the highest level of D-aspartate among various neuroendocrine cells in the rat. Here, we report that exogenous D-aspartate strongly inhibited norepinephrine-dependent melatonin synthesis in the rat pineal gland, the concentration required for 50% inhibition being 75 microM. This inhibition was due at least partly to decreased norepinephrine-dependent serotonin N-acetyltransferase activity. Upon incubation, D-aspartate was gradually released from pinealocytes and accumulated in the incubation medium as determined by high-performance liquid chromatography on a Pirkle-type chiral column. These results suggest that D-aspartate acts as a negative regulator for melatonin synthesis in the pineal gland.
Institute of Scientific and Industrial Research, Osaka University, Ibaraki, Japan.
S
S
Ishio
H
H
Yamada
M
M
Hayashi
S
S
Yatsushiro
T
T
Noumi
A
A
Yamaguchi
Y
Y
Moriyama
D000818:Animals; D001191:Arylamine N-Acetyltransferase / Q000378:metabolism; D001224:Aspartic Acid / Q000378:metabolism / Q000494:pharmacology*; D003994:Bucladesine / Q000494:pharmacology; D002478:Cells, Cultured; D002851:Chromatography, High Pressure Liquid; D017077:Culture Media, Conditioned / Q000378:metabolism; D000242:Cyclic AMP / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D018698:Glutamic Acid / Q000494:pharmacology; D008550:Melatonin / Q000096:biosynthesis*; D009924:Organ Culture Techniques; D010870:Pineal Gland / Q000187:drug effects / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D013997:Time Factors
D017077:Culture Media, Conditioned; D001224:Aspartic Acid; D018698:Glutamic Acid; D003994:Bucladesine; D000242:Cyclic AMP; D001191:Arylamine N-Acetyltransferase; D008550:Melatonin