Ultrastructural identification of neuropeptides in the central nervous system.
A number of different neuropeptides have been described within presynaptic terminals at the ultrastructural level in the central nervous system. The majority of these neuropeptides share a common morphology with one another. Terminals containing neuropeptides have a population of small, clear vesicles associated with the active zone of the synapse and a lesser number of large, granular vesicles that are located at a distance from the active site of the synapse. It is believed that the large, granular vesicles act as a mechanism for the transport/storage of the neuropeptides, while the small, clear vesicles are thought to be acting as structures responsible for the release of the neurotransmitter/neuropeptide into the synaptic cleft. The neuropeptide containing terminals most often have asymmetrical junctions associated with their presynaptic membranes, although symmetrical junctions have been described with peptide containing terminals in a number of areas in the central nervous system. Neuropeptide containing terminals contact every part of the neuronal membrane; however, the majority of synaptic contacts involve portions of the dendritic shafts. Evidence is beginning to accumulate to indicate that for certain neuropeptides there is a specific spatial arrangement to their termination along the neuronal membrane.
Maley
B E
BE
Department of Anatomy and Neurobiology, University of Kentucky Medical Center, Lexington 40536.
D000818:Animals; D001921:Brain / Q000648:ultrastructure*; D001923:Brain Chemistry; D015740:Calcitonin Gene-Related Peptide / Q000032:analysis*; D002766:Cholecystokinin / Q000032:analysis*; D004745:Enkephalins / Q000032:analysis*; D006801:Humans; D009474:Neurons / Q000032:analysis; D009496:Neurotensin / Q000032:analysis*; D013004:Somatostatin / Q000032:analysis*; D013373:Substance P / Q000032:analysis*
D004745:Enkephalins; D013373:Substance P; D009496:Neurotensin; D013004:Somatostatin; D002766:Cholecystokinin; D015740:Calcitonin Gene-Related Peptide