title: Inducible, pharmacogenetic approaches to the study of learning and memory.
abstract: Here we introduce a strategy in which pharmacology is used to induce the effects of recessive mutations. For example, mice heterozygous for a null mutation of the K-ras gene (K-ras+/-) show normal hippocampal mitogen-activated protein kinase (MAPK) activation, long-term potentiation (LTP) and contextual conditioning. However, a dose of a mitogen-activated/extracellular-signal-regulated kinase (MEK) inhibitor, ineffective in wild-type controls, blocks MAPK activation, LTP and contextual learning in K-ras+/- mutants. These indicate that K-Ras/MEK/MAPK signaling is critical in synaptic and behavioral plasticity. A subthreshold dose of NMDA receptor antagonists triggered a contextual learning deficit in mice heterozygous for a point mutation (T286A) in the alphaCaMKII gene, but not in K-ras+/- mutants, demonstrating the specificity of the synergistic interaction between the MEK inhibitor and the K-ras+/- mutation. This pharmacogenetic approach combines the high temporal specificity that pharmacological manipulations offer, with the molecular specificity of genetic disruptions.
authors.affiliation: Departments of Neurobiology, Psychiatry and Psychology, Brain Research Institute, University of California, Los Angeles, California 90095-1761, USA.
authors.forename: M
authors.initials: M
authors.lastname: Ohno
authors.forename: P W
authors.initials: PW
authors.lastname: Frankland
authors.forename: A P
authors.initials: AP
authors.lastname: Chen
authors.forename: R M
authors.initials: RM
authors.lastname: Costa
authors.forename: A J
authors.initials: AJ
authors.lastname: Silva
mesh_terms: D000818:Animals; D001362:Avoidance Learning / Q000187:drug effects / Q000502:physiology; D001369:Axons / Q000187:drug effects / Q000378:metabolism; D054732:Calcium-Calmodulin-Dependent Protein Kinase Type 2; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000172:deficiency / Q000235:genetics; D003213:Conditioning, Psychological / Q000187:drug effects / Q000502:physiology; D004558:Electric Stimulation; D004791:Enzyme Inhibitors / Q000494:pharmacology; D018691:Excitatory Amino Acid Antagonists / Q000494:pharmacology; D019706:Excitatory Postsynaptic Potentials / Q000187:drug effects / Q000502:physiology; D005239:Fear / Q000187:drug effects / Q000502:physiology; D005260:Female; D011905:Genes, ras / Q000187:drug effects* / Q000502:physiology; D006579:Heterozygote; D006624:Hippocampus / Q000187:drug effects* / Q000378:metabolism; D007858:Learning / Q000187:drug effects* / Q000502:physiology; D017774:Long-Term Potentiation / Q000187:drug effects* / Q000502:physiology; D048369:MAP Kinase Kinase 1; D020935:MAP Kinase Signaling System / Q000187:drug effects* / Q000502:physiology; D008297:Male; D008568:Memory / Q000187:drug effects* / Q000502:physiology; D051379:Mice; D018345:Mice, Knockout; D020929:Mitogen-Activated Protein Kinase Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism; D020928:Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism; D009154:Mutation / Q000187:drug effects* / Q000502:physiology; D017346:Protein Serine-Threonine Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism; D016194:Receptors, N-Methyl-D-Aspartate / Q000037:antagonists & inhibitors / Q000378:metabolism
chemical_list: D004791:Enzyme Inhibitors; D018691:Excitatory Amino Acid Antagonists; D016194:Receptors, N-Methyl-D-Aspartate; D017346:Protein Serine-Threonine Kinases; D054732:Calcium-Calmodulin-Dependent Protein Kinase Type 2; D017871:Calcium-Calmodulin-Dependent Protein Kinases; D020928:Mitogen-Activated Protein Kinases; D048369:MAP Kinase Kinase 1; C482127:Map2k1 protein, mouse; D020929:Mitogen-Activated Protein Kinase Kinases