Aβ peptide interactions with isoflurane, propofol, thiopental and combined thiopental with halothane: A NMR study

Aβ peptide is the major component of senile plaques (SP) which accumulates in AD (Alzheimer's disease) brain. Reports from different laboratories indicate that anesthetics interact with Aβ peptide and induce Aβ oligomerization. The molecular mechanism of Aβ peptide interactions with these anesthetics was not determined. We report molecular details for the interactions of uniformly 15N labeled Aβ40 with different anesthetics using 2D nuclear magnetic resonance (NMR) experiments. At high concentrations both isoflurane and propofol perturb critical amino acid residues (G29, A30 and I31) of Aβ peptide located in the hinge region leading to Aβ oligomerization. In contrast, these three specific residues do not interact with thiopental and subsequently no Aβ oligomerization was observed. However, studies with combined anesthetics (thiopental and halothane), showed perturbation of these residues (G29, A30 and I31) and subsequently Aβ oligomerization was found. Perturbation of these specific Aβ residues (G29, A30 and I31) by different anesthetics could play an important role to induce Aβ oligomerization.