5-hydroxytryptamine synthesis in HL-1 cells and neonatal rat cardiocytes.
Some reports showed that serotonergic system might have existed and that 5-hydroxytryptamine (5-HT) was detected in the hamster heart. The source of 5-HT in the heart, however, remains to be fully elucidated. So the present study was designed to define serotonergic system and to clarify which cell could produce 5-HT in the heart. As a result, 5-HT was detected in homogenates of HL-1 cardiomyocytes by high performance liquid chromatography with fluorescence detection, but not in those of neonatal rat non-cardiomyocytes (NMCs). And TPH and AADC mRNAs were expressed in HL-1 cardiomyocytes and neonatal rat cardiomyocytes (MCs), not in NMCs. mRNAs of 5-HT(2A) receptor were detected in both MCs and NMCs, and those of 5-HT(2B) receptor in NMCs. These findings definitively demonstrate that 5-HT is secreted from the myocytes of the heart and strongly implied that 5-HT might play a certain role in cardiac physiology.
Ikeda
Keiichi
K
Department of Pharmacology I, Jikei University School of Medicine, Minato-ku, Tokyo 105-8461, Japan. ikedak@jikei.ac.jp
Tojo
Katsuyoshi
K
Otsubo
Chikara
C
Udagawa
Takashi
T
Kumazawa
Kensuke
K
Ishikawa
Masahiro
M
Tokudome
Goro
G
Hosoya
Tatsuo
T
Tajima
Naoko
N
Claycomb
William C
WC
Nakao
Kazuwa
K
Kawamura
Masahiro
M
D000818:Animals; D000831:Animals, Newborn; D002460:Cell Line; D002478:Cells, Cultured; D032383:Myocytes, Cardiac / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D012701:Serotonin / Q000096:biosynthesis*
D012701:Serotonin