Differential physiologic responses of alpha7 nicotinic acetylcholine receptors to beta-amyloid1-40 and beta-amyloid1-42.

The beta-amyloid peptides (Abeta), Abeta(1-40) and Abeta(1-42), have been implicated in Alzheimer's disease (AD) pathology. Although Abeta(1-42) is generally considered to be the pathological peptide in AD, both Abeta(1-40) and Abeta(1-42) have been used in a variety of experimental models without discrimination. Here we show that monomeric or oligomeric forms of the two Abeta peptides, when interact with the neuronal cation channel, alpha7 nicotinic acetylcholine receptors (alpha7nAChR), would result in distinct physiologic responses as measured by acetylcholine release and calcium influx experiments. While Abeta(1-42) effectively attenuated these alpha7nAChR-dependent physiology to an extent that was apparently irreversible, Abeta(1-40) showed a lower inhibitory activity that could be restored upon washings with physiologic buffers or treatment with alpha7nAChR antagonists. Our data suggest a clear pharmacological distinction between Abeta(1-40) and Abeta(1-42).

Lee DH ，Wang HY 《journal of neurobiology》

Inhibitory effects of beta-amyloid on the nicotinic receptors which stimulate glutamate release in rat hippocampus: the glial contribution.

We investigated on the neuronal nicotinic acetylcholine receptor subtypes involved in the cholinergic control of in vivo hippocampal glutamate (GLU), aspartate (ASP) and inhibitory γ-aminobutyric acid (GABA) overflow. We also investigated on the possible contribution of nicotinic acetylcholine receptors subtypes present on astrocytes in the regulation of the three neurotransmitter amino acids overflow using hippocampal gliosomes and on the effects of beta-amyloid (Aβ) 1-40 on the nicotinic control of amino acid neurotransmitter release. Nicotine was able to enhance the in vivo overflow of the three amino acids being more potent in stimulating GLU overflow. The α7 selective agonist PHA543613 induced an overflow very similar to that of nicotine. The α4β2 selective agonist 5IA85380 was significantly less potent in inducing GLU overflow while the overflow of ASP and GABA were almost inconsistent. Aβ1-40 inhibited the neurotransmitter overflow stimulated by PHA543613 but not the one evoked by 5IA85380. In hippocampal gliosomes nicotine elicited selectively GLU overflow which was also evoked by 5IA85380 and by the α7 selective agonist choline. Nicotine- and choline-induced glutamate overflow in gliosomes was inhibited by Aα1-40. In conclusion nicotine administration in vivo elicits hippocampal GLU release mostly through α7 nicotinic acetylcholine receptors likely present both on neurons and astrocytes. Aβ inhibitory effect on the nicotinic-control of GLU release seems to depend primarily to the inhibition of α7 nicotinic acetylcholine receptors functional responses.

Salamone A ，Mura E ，Zappettini S ，Grilli M ，Olivero G ，Preda S ，Govoni S ，Marchi M ... -  《-》

Presynaptic alpha7 and non-alpha7 nicotinic acetylcholine receptors modulate [3H]d-aspartate release from rat frontal cortex in vitro.

Rousseau SJ ，Jones IW ，Pullar IA ，Wonnacott S ... -  《NEUROPHARMACOLOGY》

beta-Amyloid(1-42) binds to alpha7 nicotinic acetylcholine receptor with high affinity. Implications for Alzheimer's disease pathology.

Wang HY ，Lee DH ，D'Andrea MR ，Peterson PA ，Shank RP ，Reitz AB ... -  《JOURNAL OF BIOLOGICAL CHEMISTRY》

Role of Ca2+ ions in nicotinic facilitation of GABA release in mouse thalamus.

Léna C ，Changeux JP 《-》