Feline 'C'-type terminals possess synaptic sites associated with a hypolemmal cistern and Nissl body.
Previous findings suggest that axosomatic 'C'-type terminals on rat spinal motoneurones possess 'active' synaptic sites associated with the characteristic subsynaptic cistern and postsynaptic Nissl body, but 'C'-terminals in cat do not. A re-examination of feline 'C'-terminals undertook to compare the synaptic ultrastructure in aldehyde-fixed material stained by either osmium or ethanolic phosphotungstic acid (E-PTA). In agreement with previous findings osmicated cat 'C'-terminals failed to reveal synaptic complexes in regions possessing the subsynaptic cistern ('cisternal regions'). In contrast, cisternal regions of E-PTA stained 'C'-terminals exhibited a linear array of presynaptic dense projection all opposed by a single extended postsynaptic density which abutted directly onto both postsynaptic membrane and the cistern. This close topographical relationship is suggested to be functionally significant in the trans-synaptic trophism previously demonstrated for feline 'C'-terminals.
Pullen
A H
AH
Sobell Department of Neurophysiology, Institute of Neurology, London U.K.
D000818:Animals; D001369:Axons / Q000648:ultrastructure*; D002415:Cats / Q000033:anatomy & histology*; D006652:Histological Techniques; D009562:Nissl Bodies / Q000648:ultrastructure*; D013569:Synapses / Q000648:ultrastructure*; D013570:Synaptic Membranes / Q000648:ultrastructure