It is tacitly assumed that the biological role of acetylcholinesterase is termination of synaptic transmission at cholinergic synapses. However, together with its structural homolog, butyrylcholinesterase, it is widely distributed both within and outside the nervous system, and, in many cases, the role of both enzymes remains obscure. The transient appearance of the cholinesterases in embryonic tissues is especially enigmatic. The two enzymes' extra-synaptic roles, which are known as ‘non-classical’ roles, are the topic of this review. Strong evidence has been presented that AChE and BChE play morphogenetic roles in a variety of eukaryotic systems, and they do so either by acting as adhesion proteins, or as trophic factors. As trophic factors, one mode of action is to directly regulate morphogenesis, such as neurite outgrowth, by poorly understood mechanisms. The other mode is by regulating levels of acetylcholine, which acts as the direct trophic factor. Alternate substrates have been sought for the cholinesterases. Quite recently, it was shown that levels of the aggression hormone, ghrelin, which also controls appetite, are regulated by butyrylcholinesterase. The rapid hydrolysis of acetylcholine by acetylcholinesterase generates high local proton concentrations. The possible biophysical and biological consequences of this effect are discussed. The biological significance of the acetylcholinesterases secreted by parasitic nematodes is reviewed, and, finally, the involvement of acetylcholinesterase in apoptosis is considered.

人们默认乙酰胆碱酯酶的生物学作用是终止胆碱能突触的突触传递。然而，与其结构同源物丁酰胆碱酯酶一起广泛分布于神经系统内外，并且在许多情况下，这两种酶的作用仍不清楚。胚胎组织中胆碱酯酶的短暂出现尤其令人费解。这两种酶的突触外作用，被称为“非经典”作用，是本综述的主题。强有力的证据表明 AChE 和 BChE 在各种真核系统中发挥形态发生作用，它们通过充当粘附蛋白或营养因子来发挥作用。作为营养因子，一种作用方式是直接调节形态发生，如轴突生长、由知之甚少的机制。另一种模式是通过调节乙酰胆碱的水平，乙酰胆碱是直接的营养因子。已经为胆碱酯酶寻找替代底物。最近，有研究表明，控制食欲的攻击性激素生长素释放肽的水平受丁酰胆碱酯酶的调节。乙酰胆碱酯酶对乙酰胆碱的快速水解产生高局部质子浓度。讨论了这种效应可能产生的生物物理和生物学后果。综述了寄生线虫分泌的乙酰胆碱酯酶的生物学意义，最后考虑了乙酰胆碱酯酶在细胞凋亡中的作用。已经为胆碱酯酶寻找替代底物。最近，有研究表明，控制食欲的攻击性激素生长素释放肽的水平受丁酰胆碱酯酶的调节。乙酰胆碱酯酶对乙酰胆碱的快速水解产生高局部质子浓度。讨论了这种效应可能产生的生物物理和生物学后果。综述了寄生线虫分泌的乙酰胆碱酯酶的生物学意义，最后考虑了乙酰胆碱酯酶在细胞凋亡中的作用。已经为胆碱酯酶寻找替代底物。最近，有研究表明，控制食欲的攻击性激素生长素释放肽的水平受丁酰胆碱酯酶的调节。乙酰胆碱酯酶对乙酰胆碱的快速水解产生高局部质子浓度。讨论了这种效应可能产生的生物物理和生物学后果。综述了寄生线虫分泌的乙酰胆碱酯酶的生物学意义，最后考虑了乙酰胆碱酯酶在细胞凋亡中的作用。乙酰胆碱酯酶对乙酰胆碱的快速水解产生高局部质子浓度。讨论了这种效应可能产生的生物物理和生物学后果。综述了寄生线虫分泌的乙酰胆碱酯酶的生物学意义，最后考虑了乙酰胆碱酯酶在细胞凋亡中的作用。乙酰胆碱酯酶对乙酰胆碱的快速水解产生高局部质子浓度。讨论了这种效应可能产生的生物物理和生物学后果。综述了寄生线虫分泌的乙酰胆碱酯酶的生物学意义，最后考虑了乙酰胆碱酯酶在细胞凋亡中的作用。