Erb C, Klein J
Pharmakologisches Institut der Universitat Mainz, Germany.
Neurosci Lett. 1998 Jun 19;249(2-3):111-4. doi: 10.1016/s0304-3940(98)00418-2.
Following the subcutaneous (s.c.) administration of nicotinamide (10 mmol/kg), the brain and CSF levels of nicotinamide were increased to millimolar concentrations, but the concentrations of N-methylnicotinamide (NMN) in the CSF, and of NMN and NAD+ in brain tissue were not significantly altered. Concomitantly, nicotinamide caused increases of the choline levels in the venous brain blood. In hippocampal slices, nicotinamide (1-10 mM) induced choline release in a calcium- and mepacrine-sensitive manner and, in [3H]choline-labelled slices, increased the levels of [3H]lyso-phosphatidylcholine and [3H]glycerophosphocholine. We conclude that nicotinamide enhances brain choline concentrations by mobilising choline from choline-containing phospholipids, presumably via activation of phospholipase A2, while the formation of NMN does not contribute to this effect.
皮下注射烟酰胺（10 mmol/kg）后，烟酰胺在脑和脑脊液中的水平升高至毫摩尔浓度，但脑脊液中N-甲基烟酰胺（NMN）以及脑组织中NMN和NAD+的浓度未发生显著变化。同时，烟酰胺导致脑静脉血中胆碱水平升高。在海马切片中，烟酰胺（1-10 mM）以钙和米帕林敏感的方式诱导胆碱释放，并且在[3H]胆碱标记的切片中，增加了[3H]溶血磷脂酰胆碱和[3H]甘油磷酸胆碱的水平。我们得出结论，烟酰胺可能通过激活磷脂酶A2从含胆碱的磷脂中动员胆碱来提高脑胆碱浓度，而NMN的形成对此效应没有作用。
