Freeze-fracture study of synaptic contacts in the neuropil of the tuberal hypothalamus of the rainbow trout (Salmo gairdneri Rich.).
Synaptic contacts in the neuropil of the tuberal hypothalamus of the rainbow trout were examined by the freeze-fracture technique. Three types of synaptic boutons, rounded, flattened and cup-shaped were characterized. In addition, a fourth type of nerve bouton did not exhibit membrane active sites. The round and cup-shaped synaptic boutons had vesicles of 50 nm in size, but flattened boutons contained both small (50 nm) and large sized (100 nm) vesicles. The active sites at the presynaptic membrane showed pits in the P-face and craters in the corresponding E-face; the postsynaptic membranes showed clusters of IMPs in both P- and E-faces. The postsynaptic cytoplasms had clustered particles directly apposed to the active sites corresponding to the postsynaptic density; sometimes, other particle clusters appeared in the presynaptic cytoplasm corresponding here to the presynaptic grid. There also were particles in the synaptic clefts that seemed to connect the pre- and postsynaptic membranes.
Caruncho
H J
HJ
Departamento de Biología Fundamental, Universidad de Santiago de Compostela, Spain.
Rodriguez-Moldes
I
I
Lamas
J
J
Anadón
R
R
D000818:Animals; D001921:Brain / Q000648:ultrastructure; D005614:Freeze Fracturing; D007031:Hypothalamus / Q000648:ultrastructure*; D008854:Microscopy, Electron; D009474:Neurons / Q000648:ultrastructure*; D010316:Particle Size; D013569:Synapses / Q000648:ultrastructure*; D013570:Synaptic Membranes / Q000648:ultrastructure; D014337:Trout / Q000033:anatomy & histology*