|Excitability wave reaction-diffusion chicken neuron glia potassium nitric oxide glycolysis|
Spreading Depression (SD) is a transient depolarization of cells that coexists with temporary loss of neuronal functions and propagates with a velocity of 3 mm/min through neuronal tissue. All neuronal activity is suppressed during this time. However, total tissue recovery is observed after about 20 minutes. Pathophysiological processes, that take place during SD wave propagation are related to neurological disorders such as migraine aura and stroke. Not only neurologists and physiologists have been fascinated by this phenomenon, but biophysicists investigate this phenomenon as an example of self-organized pattern formation in neuronal tissue. SD propagation in chicken retina is accompanied by an intrinsic optical signal (IOS). This allows optical registration of the SD waves and focusing on spatiotemporal dynamics. The spatial resolution of this quasi non-invasive method cannot be reached by any other physiological method. Processes that take place during the second phase of IOS and their role in tissue recovery are investigated in this work. Changes in IOS under the standard conditions and in the presence of different pharmacological substances are analyzed with the help of a special parameterization, that was also developed here. According to the observed results the following hypothesis was formulated: the second phase of the IOS reflects changes in metabolic processes that supply cells with energy needed after SD wave propagation. In future investigations additional methods (for example microdyalysis sonds) should be combined with optical imaging to prove the formulated hypothesis.