[Role of histological fixation of the brain in the detection of functional changes in the size of neurons].
In the experiments performed on frogs using vital and fixed preparations, the size and structure of the spinal motoneurons have been studied. In both cases the neighbouring neurons differ in size, form and staining intensity. After the brain is fixed in Carnoy fluid and in 96% alcohol, the neuron size decreases by 34%, cytoplasm--by 35%, nucleus--by 33% and nucleolus--by 22%. The nucleus--cytoplasm ratio does not change in the neurons after fixation. After fixation the neighboring neurons decrease to various degree (from 18 up to 54%). There is no correlation between the neuron size and degree of its decreasing after the brain fixation. In the vital preparations studied the size of the motoneurons subjected to an intensive, prolonged synaptic activation does not differ from that of the control. However, after the brain fixation, their size decreases by 49%. Thus, the degree of the neuron decrease after the brain fixation surves as an index of the vital activation intensity. The neurons injured or subjected to an intensive and prolonged activation only after fixation shrink and acquire a pyknomorphous appearance.
D000200:Action Potentials; D000818:Animals; D004558:Electric Stimulation; D005404:Fixatives; D009046:Motor Neurons / Q000166:cytology* / Q000502:physiology; D011896:Rana temporaria; D013048:Specimen Handling; D013116:Spinal Cord / Q000166:cytology
D005404:Fixatives
Rol' fiksatsii mozga v vyiavlenii funktsional'no-obuslovlennykh izmeneniĭ razmerov neĭronov.