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Espadas I, Ortiz O, García-Sanz P, Sanz-Magro A, Alberquilla S, Solis O, Delgado-García JM, Gruart A, Moratalla R. Dopamine D2R is Required for Hippocampal-dependent Memory and Plasticity at the CA3-CA1 Synapse. Cereb Cortex 2021; 31:2187-2204. [PMID: 33264389 PMCID: PMC7945019 DOI: 10.1093/cercor/bhaa354] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2020] [Revised: 10/04/2020] [Accepted: 10/23/2020] [Indexed: 12/24/2022] Open
Abstract
Dopamine receptors play an important role in motivational, emotional, and motor responses. In addition, growing evidence suggests a key role of hippocampal dopamine receptors in learning and memory. It is well known that associative learning and synaptic plasticity of CA3-CA1 requires the dopamine D1 receptor (D1R). However, the specific role of the dopamine D2 receptor (D2R) on memory-related neuroplasticity processes is still undefined. Here, by using two models of D2R loss, D2R knockout mice (Drd2-/-) and mice with intrahippocampal injections of Drd2-small interfering RNA (Drd2-siRNA), we aimed to investigate how D2R is involved in learning and memory as well as in long-term potentiation of the hippocampus. Our studies revealed that the genetic inactivation of D2R impaired the spatial memory, associative learning, and the classical conditioning of eyelid responses. Similarly, deletion of D2R reduced the activity-dependent synaptic plasticity in the hippocampal CA1-CA3 synapse. Our results demonstrate the first direct evidence that D2R is essential in behaving mice for trace eye blink conditioning and associated changes in hippocampal synaptic strength. Taken together, these results indicate a key role of D2R in regulating hippocampal plasticity changes and, in consequence, acquisition and consolidation of spatial and associative forms of memory.
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Affiliation(s)
- Isabel Espadas
- Neurobiologia Funcional y de Sistemas, Instituto Cajal, CSIC, Madrid 28002, Spain
- CIBERNED, ISCIII, Madrid 28002, Spain
| | - Oscar Ortiz
- Neurobiologia Funcional y de Sistemas, Instituto Cajal, CSIC, Madrid 28002, Spain
- CIBERNED, ISCIII, Madrid 28002, Spain
| | - Patricia García-Sanz
- Neurobiologia Funcional y de Sistemas, Instituto Cajal, CSIC, Madrid 28002, Spain
- CIBERNED, ISCIII, Madrid 28002, Spain
| | - Adrián Sanz-Magro
- Neurobiologia Funcional y de Sistemas, Instituto Cajal, CSIC, Madrid 28002, Spain
- CIBERNED, ISCIII, Madrid 28002, Spain
| | - Samuel Alberquilla
- Neurobiologia Funcional y de Sistemas, Instituto Cajal, CSIC, Madrid 28002, Spain
- CIBERNED, ISCIII, Madrid 28002, Spain
| | - Oscar Solis
- Neurobiologia Funcional y de Sistemas, Instituto Cajal, CSIC, Madrid 28002, Spain
- CIBERNED, ISCIII, Madrid 28002, Spain
| | | | - Agnès Gruart
- División de Neurociencias, Univ. Pablo de Olavide, Sevilla 41013, Spain
| | - Rosario Moratalla
- Neurobiologia Funcional y de Sistemas, Instituto Cajal, CSIC, Madrid 28002, Spain
- CIBERNED, ISCIII, Madrid 28002, Spain
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