Supravital microwave experiments support that the formation of "dark" neurons is propelled by phase transition in an intracellular gel system

Ferenc Gallyas, József Pál, Péter Bukovics

Research output: Contribution to journalArticle

6 Citations (Scopus)


Background: Based on circumstantial evidences, we (Gallyas, F., Farkas, O., Mázló, M., 2004. Gel-to-gel phase transition may occur in mammalian cells: Mechanism of formation of "dark" (compacted) neurons. Biol. Cell 96, 313-324.) proposed that the formation of "dark" neurons (striking compaction of visibly normal ultrastructural elements accompanied with large-scale fluid excretion), which occur in many neurological diseases such as ischemia, proceeds with a non-enzymatic mechanism. Objective: To support this proposition, the present paper deals with the results of supravital experiments using microwave irradiation. Method: After transcardial glutaraldehyde fixation followed by decapitation, a pin was stuck into rat brains just before and just after they were warmed up to 80 °C and maintained at this temperature for various periods of time by controlled microwave irradiation. Results: Independently of the duration of irradiation, the pre-irradiation pin sticking produced numerous "dark" neurons in an approximating 500-μm-wide zone around its track whereas the post-irradiation pin sticking did the same only when the irradiation was shorter than 55 s. The excreted fluid was present in neighbouring astrocytic processes but not in the extracellular space. Conclusions: The formation of "dark" neurons is completed in less than 55 s under the circumstances of the experiment. As neurons are poor in readily consumable chemical energy in the absence of blood circulation, this rapid and massive fluid excretion cannot be explained by any enzyme-mediated membrane-related pump mechanism. An osmotic mechanism can also be discounted. In contrast, it is in conformity with the above mentioned non-enzymatic (physicochemical) phenomenon, the phase transition of a supra-cytoskeletal gel network storing free energy in the form of non-covalent interactions.

Original languageEnglish
Pages (from-to)152-156
Number of pages5
JournalBrain research
Publication statusPublished - May 13 2009


  • Gel-to-gel phase transition
  • Neuron
  • Non-covalent free energy
  • Physicochemical mechanism
  • Rat
  • Ultrastructural compaction

ASJC Scopus subject areas

  • Neuroscience(all)
  • Molecular Biology
  • Clinical Neurology
  • Developmental Biology

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