摘要：Relative reactivities of histamine and indoleamines such as tryptamine, 5-hydroxytryptamine and 5-methoxytryptamine with acetaldehyde (AA) under physiological conditions were investigated. AA was found to have much higher reactivity towards histamine than towards indoleamines. For example, when a reaction mixture of AA (1 m M ) and histamine or tryptamine (5 m M ) in 0.1 M phosphate buffer (pH 7.4) was incubated at 37 °C for 24 h, AA decreased by 11% in the case of tryptamine, while in the case of histamine, it decreased 88%. In addition, the reaction product of AA with histamine was investigated. Mixtures of a fixed amount of histamine (5 m M ) and various amounts of AA (1—20 m M ) in phosphate buffer (pH 7.4) were incubated for 5 h at 37 °C. In all cases, only one product, 4-methylspinaceamine (4-MSPA), was observed. The yield of 4-MSPA was in approximate agreement with the losses of histamine and AA, indicating that the loss of histamine caused by the reaction of AA was quantatively converted to 4-MSPA. These results show that the reaction of AA with histamine easily takes place to produce 4-MSPA in an aqueous medium close to physiological conditions.
