title: Acetyl-L-Carnitine selectively prevents post-ischemic LTP via a possible action on mitochondrial energy metabolism.
abstract: It has been hypothesized that Acetyl-L-Carnitine (ALC) contributes to mitochondrial ATP production through maintenance of key mitochondrial proteins and protects mitochondria against oxidative stress. We have investigated the role of ALC on the expression of two forms of synaptic plasticity in the striatum: (i) the physiological long-term potentiation (LTP) and (ii) the ischemic long-term potentiation (i-LTP), an aberrant form of synaptic plasticity occurring after in vitro ischemia. The application in vitro of ALC did not alter the induction or the maintenance of physiological activity-dependent LTP, while it prevented i-LTP in a dose-dependent manner. The ability of ALC to prevent i-LTP was not affected by previous application of scopolamine, a non-selective muscarinic receptors antagonist. Given the susceptibility of mitochondrial complex IV to ischemic oxidative insult, we investigated the role of this complex as possible target of ALC action. Thus, the application of a low dose of the mitochondrial toxin sodium azide, conventionally used as a model of hypoxia due to its capability to inhibit mitochondrial complex IV, induced a pathological synaptic potentiation that was fully prevented by ALC application. In the presence of a very low dose of the mitochondrial uncoupler FCCP, ALC no longer prevented i-LTP suggesting that neuroprotective effects of ALC require a compensatory activity of mitochondrial energy metabolism. Our data demonstrate that ALC exerts neuroprotective effects by preventing the expression of pathological synaptic plasticity induced by ischemia. These effects crucially depend on the ability on ALC to affect mitochondrial processes.
authors.affiliation: Laboratorio di Neurofisiologia, Fondazione Santa Lucia, IRCCS c/o CERC, Via del Fosso di Fiorano 64, 00143 Rome, Italy.
authors.forename: Vincenza
authors.initials: V
authors.lastname: Bagetta
authors.forename: Ilaria
authors.initials: I
authors.lastname: Barone
authors.forename: Veronica
authors.initials: V
authors.lastname: Ghiglieri
authors.forename: Massimiliano
authors.initials: M
authors.lastname: Di Filippo
authors.forename: Carmelo
authors.initials: C
authors.lastname: Sgobio
authors.forename: Giorgio
authors.initials: G
authors.lastname: Bernardi
authors.forename: Paolo
authors.initials: P
authors.lastname: Calabresi
authors.forename: Barbara
authors.initials: B
authors.lastname: Picconi
mesh_terms: D000108:Acetylcarnitine / Q000494:pharmacology*; D000818:Animals; D002259:Carbonyl Cyanide p-Trifluoromethoxyphenylhydrazone / Q000494:pharmacology; D015687:Cell Hypoxia / Q000187:drug effects*; D002540:Cerebral Cortex; D003342:Corpus Striatum; D004347:Drug Interactions; D004558:Electric Stimulation / Q000379:methods; D004734:Energy Metabolism / Q000187:drug effects* / Q000502:physiology; D066298:In Vitro Techniques; D007476:Ionophores / Q000494:pharmacology; D017774:Long-Term Potentiation / Q000187:drug effects* / Q000502:physiology; D008297:Male; D008928:Mitochondria / Q000378:metabolism*; D018697:Nootropic Agents / Q000494:pharmacology*; D018408:Patch-Clamp Techniques; D051381:Rats; D017208:Rats, Wistar
chemical_list: D007476:Ionophores; D018697:Nootropic Agents; D002259:Carbonyl Cyanide p-Trifluoromethoxyphenylhydrazone; D000108:Acetylcarnitine