Impaired hippocampal-dependent learning and functional abnormalities in the hippocampus in mice lacking serotonin1A receptors

Sarnyai, Zoltán, Sibille, Etienne, Pavlides, Constantine, Fenster, Robert J., McEwen, Bruce S., and Tóth, Miklós (2000) Impaired hippocampal-dependent learning and functional abnormalities in the hippocampus in mice lacking serotonin1A receptors. Proceedings of the National Academy of Sciences of the United States of America, 97 (26). pp. 14731-14736.

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Abstract

The hippocampus is a major limbic target of the brainstem serotonergic neurons that modulate fear, anxiety, and learning through postsynaptic serotonin1A receptors (5-HT1A receptors). Because chronic stress selectively down-regulates the 5-HT1A receptors in the hippocampus, we hypothesized that mice lacking these receptors may exhibit abnormalities reminiscent of symptoms of stress-related psychiatric disorders. In particular, a hippocampal deficit in the 5-HT1A receptor could contribute to the cognitive abnormalities often seen in these disorders. To test whether a deficit in 5-HT1A receptors impairs hippocampus-related functions, we studied hippocampal-dependent learning and memory, synaptic plasticity in the hippocampus, and limbic neuronal excitability in 5-HT1A-knockout (KO) mice. 5-HT1A-KO animals showed a deficit in hippocampal-dependent learning and memory tests, such as the hidden platform (spatial) version of the Morris water maze and the delayed version of the Y maze. The performance of KO mice was not impaired in nonhippocampal memory tasks such as the visible platform (nonspatial) version of the Morris water maze, the immediate version of the Y maze, and the spontaneous-alternation test of working memory. Furthermore, paired-pulse facilitation in the dentate gyrus of the hippocampus was impaired in 5-HT1A-KO mice. Finally, 5-HT1A-KO mice, as compared with wild-type animals, displayed higher limbic excitability manifested as lower seizure threshold and higher lethality in response to kainic acid administration. These results demonstrate that 5-HT1A receptors are required for maintaining normal hippocampal functions and implicate a role for the 5-HT1A receptor in hippocampal-related symptoms, such as cognitive disturbances, in stress-related disorders.

Item ID: 35110
Item Type: Article (Research - C1)
ISSN: 1091-6490
Funders: National Alliance for Research on Schizophrenia and Depression (NARSAD), Pharmaceutical Research and Manufacturers of America, National Institute of Health (NIH), USA
Projects and Grants: NIH MH58669, NIH NS34151, NIH MH41256
Date Deposited: 29 Aug 2014 05:36
FoR Codes: 11 MEDICAL AND HEALTH SCIENCES > 1109 Neurosciences > 110903 Central Nervous System @ 60%
11 MEDICAL AND HEALTH SCIENCES > 1103 Clinical Sciences > 110319 Psychiatry (incl Psychotherapy) @ 10%
17 PSYCHOLOGY AND COGNITIVE SCIENCES > 1701 Psychology > 170101 Biological Psychology (Neuropsychology, Psychopharmacology, Physiological Psychology) @ 30%
SEO Codes: 92 HEALTH > 9201 Clinical Health (Organs, Diseases and Abnormal Conditions) > 920111 Nervous System and Disorders @ 100%
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