机体的一切生命现象都依赖细胞内、外的信息传递和调控,信号传递始于细胞外信号与细胞膜上受体结合,故神经递质、激素或药物称为第一信使。大多数第一信使与受体结合后,经鸟苷酸调节蛋白(G蛋白)在细胞内产生其它化学物质,称为第二信使,再磷酸化相应的蛋白质,最终引起细胞功能性 All the body’s life phenomena are dependent on intracellular and extracellular information transmission and regulation. Signal transmission begins when extracellular signals are bound to receptors on the cell membrane. Therefore, neurotransmitters, hormones or drugs are called first messengers. After the first messenger binds to the receptor, the first messenger, a second messenger, is produced by the guanylin-regulating protein (G-protein) that re-phosphorylates the corresponding protein, ultimately resulting in cellular functionality