Читать книгу Canine and Feline Epilepsy - Luisa De Risio - Страница 41

Within a single neuron, prolonged depolarizations with sustained action-potential firing may be triggered by a brief depolarizing pulse, as in the paroxysmal depolarizing shift, or may be the result of sustained excitatory synaptic input from neighbouring neurons engaged in seizure activity (Ayala, 1983). Intrinsic mechanisms of seizure termination active in a single neuron, discussed below, include: the potassium currents activated by calcium and sodium entry; the loss of ionic gradients, particularly of potassium, leading first to depolarization with increased firing, followed by depolarization blockade of membrane firing and cessation of firing; and possibly the depletion of energy substrates locally, with the decline in adenosine triphosphate (ATP), resulting in cessation of neuronal firing.