Isoflurane-induced neuronal apoptosis in developing hippocampal neurons

Area of Science:

• Neuroscience
• Anesthesiology
• Cell Biology

Background:

• Isoflurane is a widely used anesthetic agent.
• Neuronal apoptosis and calcium overload are potential adverse effects of anesthetics.
• The precise mechanisms underlying isoflurane-induced neurotoxicity are not fully understood.

Purpose of the Study:

• To investigate the role of the P2X7 receptor and inositol triphosphate receptor in isoflurane-induced neuronal apoptosis.
• To elucidate the mechanisms of intracellular calcium overload caused by isoflurane in cultured rat hippocampal neurons.

Main Methods:

• Primary cultures of embryonic rat hippocampal neurons were used.
• Isoflurane exposure was administered to induce apoptosis and calcium overload.
• Pharmacological blockers for P2X7 and inositol triphosphate receptors were employed.
• Extracellular calcium levels were manipulated.
• Patch-clamp electrophysiology was used to assess P2X7 channel activity.
• Western blotting was used to evaluate P2X7 receptor protein expression.

Main Results:

• Isoflurane induced significant neuronal apoptosis and increased cytoplasmic calcium levels.
• Blockade of P2X7 receptors or combined blockade of inositol triphosphate receptors and removal of extracellular calcium completely prevented isoflurane's effects.
• Isoflurane directly activated P2X7-gated channels, leading to inward currents, without altering P2X7 receptor protein expression.

Conclusions:

• Isoflurane-induced neuronal apoptosis in developing rat brains is mediated by intracellular calcium overload.
• This calcium overload results from P2X7 receptor-mediated calcium influx and inositol triphosphate receptor-mediated calcium release.
• The P2X7 receptor is a key target involved in the neurotoxic effects of isoflurane.