Catechol-O-methyltransferase inhibition improves set-shifting performance and elevates stimulated dopamine release in the rat prefrontal cortex
The Val 158 Met polymorphism of the human catechol-O-methyltransferase (COMT) gene affects activity of the enzyme and influences performance and efficiency of the prefrontal cortex (PFC); however, although catecholaminergic neurotransmission is implicatedm the underlying mechanisms remain elusive be...
| Main Authors: | , , , |
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| Format: | Journal article |
| Language: | English |
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Society for Neuroscience
2004
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| _version_ | 1797057852850831360 |
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| author | Tunbridge, E Bannerman, D Sharp, T Harrison, P |
| author_facet | Tunbridge, E Bannerman, D Sharp, T Harrison, P |
| author_sort | Tunbridge, E |
| collection | OXFORD |
| description | The Val 158 Met polymorphism of the human catechol-O-methyltransferase (COMT) gene affects activity of the enzyme and influences performance and efficiency of the prefrontal cortex (PFC); however, although catecholaminergic neurotransmission is implicatedm the underlying mechanisms remain elusive because studies of the role of COMT in PFC function are sparse. This study investigated the effect of tolcapone, a brain-penetrant COMT inhibitor, on a rat model of attentional set shifting, which is dependent on catecholamines and the medial PFC (MPFC). Additionally, we investigated the effect of tolcapone on extracellular catecholamines in the mPFC using microdialysis in awake rats. Tolcapone significantly and specifically improved extradimensional (ED) set shifting. Tolcapone did not affect basal extracellular catecholamines, but significantly potentiated the increase in extracellular dopamine (DA) elicited by either local administration of the depolarizing agent potassium chloride or systematic administration of the antipsychotic agent clozapine. Although extracellular norepinephrine (NE) was also elevated by local depolarization and clozapine, the increase was not enhanced by tolcapone. We conclude that COMT activity specifically affects ED set shifting and is a significant modulator of mPFC DA but not NE under conditions of increased catecholaminergic transmission. These data suggest that the links between COMT activity and PFC function can be modeled in rats and may be specifically mediated by DA. The interaction between clozapine and tolcapone may have implications for the treatment of schizophrenia. |
| first_indexed | 2024-03-06T19:42:17Z |
| format | Journal article |
| id | oxford-uuid:2116fa24-71fb-4371-901c-93b314c9a695 |
| institution | University of Oxford |
| language | English |
| last_indexed | 2024-03-06T19:42:17Z |
| publishDate | 2004 |
| publisher | Society for Neuroscience |
| record_format | dspace |
| spelling | oxford-uuid:2116fa24-71fb-4371-901c-93b314c9a6952022-03-26T11:31:19ZCatechol-O-methyltransferase inhibition improves set-shifting performance and elevates stimulated dopamine release in the rat prefrontal cortexJournal articlehttp://purl.org/coar/resource_type/c_dcae04bcuuid:2116fa24-71fb-4371-901c-93b314c9a695PsychiatryPharmacologyExperimental psychologyEnglishOxford University Research Archive - ValetSociety for Neuroscience2004Tunbridge, EBannerman, DSharp, THarrison, PThe Val 158 Met polymorphism of the human catechol-O-methyltransferase (COMT) gene affects activity of the enzyme and influences performance and efficiency of the prefrontal cortex (PFC); however, although catecholaminergic neurotransmission is implicatedm the underlying mechanisms remain elusive because studies of the role of COMT in PFC function are sparse. This study investigated the effect of tolcapone, a brain-penetrant COMT inhibitor, on a rat model of attentional set shifting, which is dependent on catecholamines and the medial PFC (MPFC). Additionally, we investigated the effect of tolcapone on extracellular catecholamines in the mPFC using microdialysis in awake rats. Tolcapone significantly and specifically improved extradimensional (ED) set shifting. Tolcapone did not affect basal extracellular catecholamines, but significantly potentiated the increase in extracellular dopamine (DA) elicited by either local administration of the depolarizing agent potassium chloride or systematic administration of the antipsychotic agent clozapine. Although extracellular norepinephrine (NE) was also elevated by local depolarization and clozapine, the increase was not enhanced by tolcapone. We conclude that COMT activity specifically affects ED set shifting and is a significant modulator of mPFC DA but not NE under conditions of increased catecholaminergic transmission. These data suggest that the links between COMT activity and PFC function can be modeled in rats and may be specifically mediated by DA. The interaction between clozapine and tolcapone may have implications for the treatment of schizophrenia. |
| spellingShingle | Psychiatry Pharmacology Experimental psychology Tunbridge, E Bannerman, D Sharp, T Harrison, P Catechol-O-methyltransferase inhibition improves set-shifting performance and elevates stimulated dopamine release in the rat prefrontal cortex |
| title | Catechol-O-methyltransferase inhibition improves set-shifting performance and elevates stimulated dopamine release in the rat prefrontal cortex |
| title_full | Catechol-O-methyltransferase inhibition improves set-shifting performance and elevates stimulated dopamine release in the rat prefrontal cortex |
| title_fullStr | Catechol-O-methyltransferase inhibition improves set-shifting performance and elevates stimulated dopamine release in the rat prefrontal cortex |
| title_full_unstemmed | Catechol-O-methyltransferase inhibition improves set-shifting performance and elevates stimulated dopamine release in the rat prefrontal cortex |
| title_short | Catechol-O-methyltransferase inhibition improves set-shifting performance and elevates stimulated dopamine release in the rat prefrontal cortex |
| title_sort | catechol o methyltransferase inhibition improves set shifting performance and elevates stimulated dopamine release in the rat prefrontal cortex |
| topic | Psychiatry Pharmacology Experimental psychology |
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