Prussian blue technique is prone to yield false negative results in magnetoreception research

Abstract

Overview

Perls's Prussian blue staining technique has been traditionally used in magnetoreception research to identify iron-rich structures in tissues as potential indicators of magnetoreceptor structures.

Findings

• The technique has identified structures in the upper beak of birds, but these were either irreproducible or located in non-neuronal cells.
• In night-migratory songbirds, significant staining was found, though these were not associated with nerve fiber terminals.
• No staining was observed in the lamina propria of rainbow trout or in magnetotactic bacteria, even though these are known locations for magnetoreceptors.

Conclusion

The inability to effectively stain single-domain magnetite in control samples points to a significant limitation of this technique. It suggests that past influential studies may have been compromised, limiting their effectiveness in detecting true magnetic receptors. Despite this, the technique may still be useful for identifying tissue contamination by iron-rich dust.