Issue Archive

Excess nicotinamide increases plasma serotonin and histamine levels

TIAN Yan-Jie, Li Da, Ma Qiang, GU Xin-Yi, GUO Ming, LUN Yong-Zhi, SUN Wu-Ping, WANG Xin-Yuan, CAO Yu, ZHOU Shi-Sheng

Institute of Basic Medical Sciences, Medical College, Dalian University, Dalian 116622, China； Department of Neurology, Zhongshan Hospital Affiliated to Dalian University, Dalian 116001, China； College of Environmental and Chemical Engineering, Dalian University, Dalian 116622, China； Department of Physiology, Institute of Basic Medical Sciences, China Medical University, Shenyang 110001, China

Abstract

Methylation, a methyl group-consuming reaction, plays a key role in the degradation (i.e., inactivation) of monoamine neurotransmitters, including catecholamines, serotonin and histamine. Without labile methyl groups, the methylation-mediated degradation cannot take place. Although high niacin (nicotinic acid and nicotinamide) intake, which is very common nowadays, is known to deplete the body's methyl-group pool, its effect on monoamine-neurotransmitter degradation is not well understood. The aim of this article was to investigate the effect of excess nicotinamide on the levels of plasma serotonin and histamine in healthy subjects. Urine and venous blood samples were collected from nine healthy male volunteers before and after oral loading with 100 mg nicotinamide. Plasma N(1)-methylnicotinamide, urinary N(1)-methyl-2-pyridone-5-carboxamide (2-Py), and plasma betaine levels were measured by using high-performance liquid chromatography (HPLC). Plasma concentrations of choline, serotonin and histamine were measured using commercial kits. The results showed that the plasma N(1)-methylnicotinamide level and the urinary excretion of 2-Py significantly increased after oral loading with 100 mg nicotinamide, which was accompanied with a decrease in the methyl-group donor betaine. Compared with those before nicotinamide load, five-hour postload plasma serotonin and histamine levels significantly increased. These results suggest that excess nicotinamide can disturb monoamine-neurotransmitter metabolism. These findings may be of significance in understanding the etiology of monoamine-related mental diseases, such as schizophrenia and autism (a neurodevelopmental disorder).

Key words: nicotinamide; serotonin; histamine; monoamine neurotransmitters; mental disorders; autism

Received: 2012-06-06　　Accepted: 2012-07-13

Corresponding author: 周士胜　　E-mail: zhouss@dlu.edu.cn

Citing This Article：

TIAN Yan-Jie, Li Da, Ma Qiang, GU Xin-Yi, GUO Ming, LUN Yong-Zhi, SUN Wu-Ping, WANG Xin-Yuan, CAO Yu, ZHOU Shi-Sheng. Excess nicotinamide increases plasma serotonin and histamine levels. Acta Physiol Sin 2013; 65 (1): 33-38 (in Chinese with English abstract).