Moore R Y
Department of Psychiatry, University of Pittsburgh, Pennsylvania 15261.
Ann N Y Acad Sci. 1993 Sep 24;695:1-9. doi: 10.1111/j.1749-6632.1993.tb23018.x.
Neurons in the central nervous system communicate almost exclusively by the production and release at synapses of a series of molecules that are designated transmitters. Three such molecules make up the major transmitters, GABA, glutamate, and acetylcholine. GABA neurons are the principal inhibitory neurons and, as such, are the major local circuit neurons of the brain. They also are projection neurons in a number of systems. Glutamate neurons are excitatory projection neurons, particularly of the cerebral cortex, thalamus and retina. Acetylcholine neurons are excitatory neurons in ascending brainstem and basal forebrain systems and in cranial and spinal motor neurons and neurons of the sympathetic and parasympathetic systems. The catecholamines, dopamine and norepinephrine, are transmitters in several systems in brain. Dopamine is present in midbrain neurons projecting to the neostriatum, basal forebrain and cerebral cortex. It is also produced by hypothalamic neurons projecting to the median eminence and pituitary. These systems are highly topographically organized in contrast to the norepinephrine systems. The locus coeruleus norepinephrine system projects principally to thalamus, cerebral cortex and cerebellar cortex whereas the lateral tegmental system projects primarily to basal forebrain, hypothalamus, brainstem and spinal cord. The serotonin neurons of the brainstem raphe also project widely over the neuraxis, midbrain raphe neurons primarily to diencephalon and telencephalon and pontine medullary neurons to brainstem and spinal cord. There are smaller neuronal groups that produce glycine or histamine. At the present time, it appears that most, if not all, CNS neurons produce one of these small molecule transmitters. In many instances, these molecules are colocalized with one or more peptides that appear to modify the postsynaptic action of the small molecule transmitter.
中枢神经系统中的神经元几乎完全通过在突触处产生和释放一系列被指定为递质的分子来进行通信。三种这样的分子构成了主要递质，即γ-氨基丁酸（GABA）、谷氨酸和乙酰胆碱。GABA能神经元是主要的抑制性神经元，因此是大脑中主要的局部回路神经元。它们在许多系统中也是投射神经元。谷氨酸能神经元是兴奋性投射神经元，特别是在大脑皮层、丘脑和视网膜中。乙酰胆碱能神经元是脑干和基底前脑上行系统以及颅神经和脊髓运动神经元以及交感和副交感神经系统神经元中的兴奋性神经元。儿茶酚胺类，多巴胺和去甲肾上腺素，是大脑中几个系统的递质。多巴胺存在于投射到新纹状体、基底前脑和大脑皮层的中脑神经元中。它也由投射到正中隆起和垂体的下丘脑神经元产生。与去甲肾上腺素系统相比，这些系统具有高度的拓扑组织。蓝斑去甲肾上腺素系统主要投射到丘脑、大脑皮层和小脑皮层，而外侧被盖系统主要投射到基底前脑、下丘脑、脑干和脊髓。脑干中缝的5-羟色胺能神经元也广泛投射到神经轴上，中脑缝际神经元主要投射到间脑和端脑，脑桥延髓神经元投射到脑干和脊髓。有较小的神经元群产生甘氨酸或组胺。目前看来，即使不是全部，大多数中枢神经系统神经元都会产生这些小分子递质中的一种。在许多情况下，这些分子与一种或多种肽共定位，这些肽似乎会改变小分子递质的突触后作用。
