title: Nonclassical neuronal communications.
abstract: Examples from classical neuronal communications are discussed in the light of biochemical and anatomical data. These are the nonsynaptic axo-axonic interactions of the enkephalinergic neurons on nerve terminals of peptidergic primary sensory afferents and dopaminergic nigrostriatal fibers. Examples of dendrites as presynaptic sites are discussed in three very different situations, namely, the dopaminergic dendrites of the substantia nigra neurons, the gamma-aminobutyric acid--ergic dendrites involved in reciprocal dendro-dendritic synapses in the olfactory bulb, and the peripheral branches of the substance P-containing primary sensory neurons.
mesh_terms: D000818:Animals; D001369:Axons / Q000502:physiology; D001921:Brain / Q000166:cytology; D002450:Cell Communication; D003712:Dendrites / Q000502:physiology; D004298:Dopamine / Q000502:physiology; D004723:Endorphins / Q000502:physiology; D004745:Enkephalins / Q000378:metabolism; D006651:Histocytochemistry; D006801:Humans; D007158:Immunologic Techniques; D008854:Microscopy, Electron; D009411:Nerve Endings / Q000502:physiology; D009474:Neurons / Q000502:physiology* / Q000648:ultrastructure; D009475:Neurons, Afferent / Q000502:physiology; D009830:Olfactory Bulb / Q000166:cytology; D013116:Spinal Cord / Q000166:cytology; D013373:Substance P / Q000378:metabolism; D013378:Substantia Nigra / Q000166:cytology; D009435:Synaptic Transmission; D005680:gamma-Aminobutyric Acid / Q000502:physiology
chemical_list: D004723:Endorphins; D004745:Enkephalins; D013373:Substance P; D005680:gamma-Aminobutyric Acid; D004298:Dopamine