Final answer:
The accumulation inside neurons in affected areas, notably during ischemic events like a stroke, is an excessive amount of sodium and water, leading to a sodium/potassium imbalance and contributing to cellular dysfunction and potential irreversible damage.Option 1 is the correct answer.
Step-by-step explanation:
The accumulation inside the neurons in the affected area is primarily of sodium and water. When astrocytes become reactive, perhaps due to a stroke or other ischemic events, they impair their ability to maintain the local chemical environment. This impairment leads to the loss of their potassium (K+) buffering ability, and the Na+/K+ pump that ordinarily helps maintain the balance of ions inside and outside of neurons is compromised.
This can result in a sodium/potassium imbalance, with sodium ions 'leaking' into body cells and negatively impacting cellular function. During ischemic events such as a stroke, extracellular potassium levels are elevated, and if the imbalance is severe, it can lead to irreversible cellular damage. Furthermore, an excessive accumulation of calcium inside the neurons also plays a critical role in the excitotoxicity that leads to neuronal death in acute and chronic neurodegenerative diseases.