Microwave fixation and localization of calcium in synaptic terminals using x-ray microanalysis and electron energy loss spectroscopy imaging.
The distribution of calcium ions is demonstrated in synaptic terminals by means of a two-step chemical precipitation of calcium ions in the rat brain. K-oxalate/K-antimonate chemical replacement with simultaneous computerized microwave irradiation was used. This precipitate in nerve cell structures was investigated by computerized electron probe x-ray microanalysis (EDX) and electron energy loss spectroscopic (EELS) imaging. The values obtained by EDX agreed with those of the standard sample and theoretical values of Ca-antimonate. Typical EELS spectra of Ca:L, O:K, and Sb:M were obtained from nerve terminals in the same tissue block as that used for EDX analysis. Excellent net Ca:L and Sb:M EELS digital images were obtained after their background images were subtracted. Calcium ions were distributed in the nerve terminals, synaptic vesicles, mitochondria, and synaptic membranes.
Mizuhira
V
V
Medical Research Institute, Tokyo Medical and Dental University, Japan.
Hasegawa
H
H
D000818:Animals; D002118:Calcium / Q000032:analysis*; D011232:Chemical Precipitation; D004577:Electron Probe Microanalysis; D008854:Microscopy, Electron / Q000379:methods*; D008872:Microwaves; D017729:Presynaptic Terminals / Q000737:chemistry / Q000528:radiation effects*; D051381:Rats; D012815:Signal Processing, Computer-Assisted
D002118:Calcium