paroxysmal depolarization shift
Also written as: PDS — paroxysmal depolarization shift
A prolonged depolarization of neurons that underlies epileptic seizure activity, characterized by sustained calcium influx.
Full Definition
A paroxysmal depolarization shift (PDS) is a large, prolonged depolarization of neuronal membrane potential that serves as the cellular basis of epileptic activity. During a PDS, neurons experience sustained depolarization lasting 50-200 milliseconds, accompanied by a burst of action potentials followed by a prolonged afterhyperpolarization. This event is mediated by voltage-gated calcium channels and NMDA receptors, leading to excessive calcium influx. PDSs are the fundamental building blocks of epileptic seizures and can be recorded both intracellularly and extracellularly during seizure activity.
Usage
Usage note: Commonly abbreviated as PDS in epilepsy literature.
In Context
- "Intracellular recordings revealed paroxysmal depolarization shifts preceding seizure onset." — Epilepsy research paper
- "The antiepileptic drug reduced the frequency of paroxysmal depolarization shifts in the hippocampal slice preparation." — Pharmacological study