Molecular ontogeny of major neurotransmitter receptor systems in the mammalian central nervous system: Norepinephrine, dopamine, serotonin, acetylcholine, and glycine

Neurotransmitter receptors are critical elements in intercellular signaling within the central nervous system and are divided into two major types bas ed on their molecular structure and biophysical properties. The first are i onotropic receptors-ligand-gated ion channels that directly affect the memb rane potential via passage of permeant ions (such as sodium and calcium) an d mediate fast synaptic transmission. The second type are slower metabotrop ic receptors that are also ligand gated but depend on an interaction with g uanine nucleotide-binding proteins and mediate signal transduction by activ ating second-messenger systems within the cell. In the past two decades, a wealth of information has emerged regarding the molecular biology and pharm acology of classic neurotransmitter receptors (including adrenergic, dopami nergic, serotonergic, cholinergic, glycine, gamma -aminobutyric acid [GABA( A)], and glutamate receptors). Further, the distribution of subunits compri sing these receptors has been extensively studied. This review focuses on t he molecular ontogeny of several of the major neurotransmitter receptor sys tems in the mammalian central nervous system, highlighting the role that so me of these may play during brain development and in certain pathologic sta tes.