title: Effects of HMG-CoA reductase inhibitors on learning and memory in the guinea pig.
abstract: Statins reduce the risk of death from cardiovascular disease in millions of people worldwide. Recent pharmacovigilance data has suggested that people taking statins have an increased risk of psychiatric adverse events such as amnesia and anxiety. This study aimed to investigate the possibility of statin-induced amnesia through animal models of memory and learning. We conducted extracellular field recordings of synaptic transmission in area CA1 of hippocampal slices to examine the effects of acute cholesterol lowering with lipid lowering drugs. We also assessed the effect of six weeks of simvastatin (2mg/kg/d) and atorvastatin (1mg/kg/d) treatment using the Morris water maze. Long Term Potentiation (LTP) was significantly diminished in the presence of 3µM atorvastatin or simvastatin and by the cholesterol sequestering agent methyl-β-cyclodextrin (MBCD). The effects were reversed in the MBCD but not the statin treated slices by the addition of cholesterol. In the water maze, statin treatment did not cause any deficits in the first five days of reference memory testing, but statin treated guinea pigs preformed significantly worse than control animals in a working memory test. The deficits observed in our experiments in water maze performance and hippocampal LTP are suggestive of statin induced changes in hippocampal plasticity. The effects on LTP are independent of cholesterol regulation, and occur at concentrations that may be relevant to clinical use. Our results may help to explain some of the behavioural changes reported in some people after beginning statin treatment.
authors.affiliation: Department of Pharmacology and Toxicology, School of Medical Sciences, University of Otago, P.O. Box 913, Dunedin, New Zealand.
authors.forename: Simran
authors.initials: S
authors.lastname: Maggo
authors.affiliation: Department of Pharmacology and Toxicology, School of Medical Sciences, University of Otago, P.O. Box 913, Dunedin, New Zealand. Electronic address: john.ashton@otago.ac.nz.
authors.forename: John C
authors.initials: JC
authors.lastname: Ashton
mesh_terms: D000647:Amnesia / Q000139:chemically induced / Q000503:physiopathology; D000818:Animals; D000069059:Atorvastatin; D001522:Behavior, Animal / Q000187:drug effects; D006168:Guinea Pigs; D006538:Heptanoic Acids / Q000009:adverse effects / Q000494:pharmacology*; D006624:Hippocampus / Q000187:drug effects / Q000502:physiology; D019161:Hydroxymethylglutaryl-CoA Reductase Inhibitors / Q000009:adverse effects / Q000494:pharmacology*; D017774:Long-Term Potentiation / Q000187:drug effects; D008297:Male; D018782:Maze Learning / Q000187:drug effects*; D008568:Memory / Q000187:drug effects*; D011758:Pyrroles / Q000009:adverse effects / Q000494:pharmacology*; D019821:Simvastatin / Q000009:adverse effects / Q000494:pharmacology*; D009435:Synaptic Transmission / Q000187:drug effects
chemical_list: D006538:Heptanoic Acids; D019161:Hydroxymethylglutaryl-CoA Reductase Inhibitors; D011758:Pyrroles; D000069059:Atorvastatin; D019821:Simvastatin
keywords: Guinea pig; Hippocampus; Long-term potentiation; Memory; Morris water maze; Statin