The application of energy-filtering electron microscopy for the cytochemical localization of Ca(2+)-ATPase activity in synaptic terminals.
The energy-filtering electron microscopical modes of electron energy-loss spectroscopy (EELS) and electron spectroscopic imaging (ESI) have been applied to the cytochemical detection of Ca(2+)-ATPase activity in synaptic terminals in the brain of a cichlid fish. Using a recently developed modification of an enzyme-histochemical method, cerium phosphate was precipitated as a marker of high-affinity Ca(2+)-ATPase activity. This is considered to be a marker for the plasmalemma-bound calcium pump, an enzyme which plays a crucial role in the regulation of the cytoplasmic calcium concentrations and therefore of the reactivity of nerve cells. High-affinity Ca(2+)-ATPase activity is located preferentially at the inner side of synaptic plasma membranes and enables a discrimination of different types of synapse. It is only by using EELS and ESI that the very small amounts of high-affinity Ca(2+)-ATPase reaction product can be analysed reliably and located precisely. These new electron microscopical techniques offer powerful tools for cytochemical studies.
Körtje
K H
KH
Institute of Zoology, University Stuttgart-Hohenheim, Germany.
Körtje
D
D
Rahmann
H
H
D000818:Animals; D001921:Brain / Q000201:enzymology* / Q000648:ultrastructure; D000252:Calcium-Transporting ATPases / Q000032:analysis*; D002563:Cerium / Q000032:analysis; D006651:Histocytochemistry; D008854:Microscopy, Electron; D010471:Perches; D010710:Phosphates / Q000032:analysis; D013057:Spectrum Analysis; D013569:Synapses / Q000201:enzymology*
D010710:Phosphates; D002563:Cerium; D000252:Calcium-Transporting ATPases; C048083:cerium phosphate