The laser microprobe mass analysis technique in the studies of the inner ear

Laser microprobe mass analysis (LAMMA) has been used to investigate cation and anion concentration in shock frozen, freeze-dried and plastic embedded inner ear tissue. Dissected inner ear specimens were prepared in various media of known ionic compositions and the influence on the K/Na ratio was measured in the lateral cochlea wall (spiral ligament, stria vascularis). For control purposes of the various procedures employed, muscle specimens (external standard) were processed in parallel. It was found that there is a good correlation between the K/Na ratio and the preservation of the tissue fine structure by comparing the results in tissues with different degrees of freezing damage.