Constitutive Activation of Gαs within Forebrain Neurons Causes Deficits in Sensorimotor Gating Because of PKA-Dependent Decreases in cAMP
| Autor: | David A. Rapoport, Gary S. Wand, Stephen J. Kanes, Xioaju Yang, Steven J. Siegel, Ted Abel, Michy P. Kelly, Sara A. Fabian, Michael F. Esposito, York Fong Cheung, Miles D. Houslay, Carolina Isiegas, Jan Tokarczyk |
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| Jazyk: | angličtina |
| Rok vydání: | 2006 |
| Předmět: |
Reflex
Startle Gs alpha subunit Mice Transgenic Gating Article Adenylyl cyclase chemistry.chemical_compound Mice Prosencephalon medicine Cyclic AMP GTP-Binding Protein alpha Subunits Gs Animals Protein kinase A Protein Kinase Inhibitors Rolipram Gait Disorders Neurologic Pharmacology Brain Chemistry Neurons Analysis of Variance Behavior Animal Phosphodiesterase Dose-Response Relationship Radiation Thionucleotides Cyclic AMP-Dependent Protein Kinases Mice Inbred C57BL Psychiatry and Mental health Amphetamine medicine.anatomical_structure chemistry Acoustic Stimulation Forebrain Dopamine Antagonists Haloperidol Neuron Neuroscience medicine.drug |
| Popis: | Sensorimotor gating, the ability to automatically filter sensory information, is deficient in a number of psychiatric disorders, yet little is known of the biochemical mechanisms underlying this critical neural process. Previously, we reported that mice expressing a constitutively active isoform of the G-protein subunit Galphas (Galphas(*)) within forebrain neurons exhibit decreased gating, as measured by prepulse inhibition of acoustic startle (PPI). Here, to elucidate the biochemistry regulating sensorimotor gating and to identify novel therapeutic targets, we test the hypothesis that Galphas(*) causes PPI deficits via brain region-specific changes in cyclic AMP (cAMP) signaling. As predicted from its ability to stimulate adenylyl cyclase, we find here that Galphas(*) increases cAMP levels in the striatum. Suprisingly, however, Galphas(*) mice exhibit reduced cAMP levels in the cortex and hippocampus because of increased cAMP phosphodiesterase (cPDE) activity. It is this decrease in cAMP that appears to mediate the effect of Galphas(*) on PPI because Rp-cAMPS decreases PPI in C57BL/6J mice. Furthermore, the antipsychotic haloperidol increases both PPI and cAMP levels specifically in Galphas(*) mice and the cPDE inhibitor rolipram also rescues PPI deficits of Galphas(*) mice. Finally, to block potentially the pathway that leads to cPDE upregulation in Galphas(*) mice, we coexpressed the R(AB) transgene (a dominant-negative regulatory subunit of protein kinase A (PKA)), which fully rescues the reductions in PPI and cAMP caused by Galphas(*). We conclude that expression of Galphas(*) within forebrain neurons causes PPI deficits because of a PKA-dependent decrease in cAMP and suggest that cAMP PDE inhibitors may exhibit antipsychotic-like therapeutic effects. |
| Databáze: | OpenAIRE |
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