Regulation of pyridoxal-5'-phosphate level by biogenic amines in mouse brain.
We investigated the relationship between the concentration of pyridoxal-5'-phosphate (PLP) and biogenic amine in mouse brain. The production of PLP from pyridoxal (PL) by pyridoxal kinase (PLK) was inhibited by the addition of dopamine (DA), norepinephrine (NE) and 5-hydroxytryptamine (5-HT), but not by that of epinephrine and N-acetyl-serotonin. DA and NE were combined with PLP by a non-enzymatic reaction, whereas 5-HT was bound only slightly with PLP. The conjugated product of PLP with DA was also detected by HPLC analysis when PLK activity was assayed using PL as a substrate in the presence of DA. In an in vivo investigation, the depletion of DA and 5-HT in mouse brain after an intraperitoneal injection of 5 mg/kg reserpine, led to slight elevation of the PLP level to 120% of the control level. By contrast, the increase in DA in the brain caused by intraperitoneal administration of 150 mg/kg L-DOPA caused the PLP concentration to decrease to 70% of the control level. However, no change in PLK activity in the brain was observed when the mice were treated with either reserpine or L-DOPA. These results suggested that the level of PLP in mouse brain was partly regulated by the concentration of biogenic amines, such as DA, NE and 5-HT, without apparent induction of PLK.
Asakura
T
T
Department of Biochemistry 1, Jikei University School of Medicine, Minato-ku, Tokyo, Japan.
Takahashi
N
N
Hirakawa
T
T
Ohkawa
K
K
Hibi
N
N
D000818:Animals; D001679:Biogenic Amines / Q000737:chemistry / Q000378:metabolism / Q000502:physiology*; D001921:Brain / Q000378:metabolism*; D004298:Dopamine / Q000737:chemistry / Q000378:metabolism*; D008297:Male; D051379:Mice; D008813:Mice, Inbred ICR; D009638:Norepinephrine / Q000378:metabolism; D011732:Pyridoxal Phosphate / Q000737:chemistry / Q000378:metabolism*; D012701:Serotonin / Q000378:metabolism
D001679:Biogenic Amines; D012701:Serotonin; D011732:Pyridoxal Phosphate; D004298:Dopamine; D009638:Norepinephrine