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Effect of a hallucinogenic serotonin 5‐HT 2A receptor agonist on visually guided, hippocampal‐dependent spatial cognition in C57BL/6J mice
Author(s) -
Zhang Gongliang,
Cinalli David,
Stackman Robert W.
Publication year - 2017
Publication title -
hippocampus
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.767
H-Index - 155
eISSN - 1098-1063
pISSN - 1050-9631
DOI - 10.1002/hipo.22712
Subject(s) - neuroscience , serotonergic , hippocampal formation , psychology , morris water navigation task , agonist , hippocampus , water maze , serotonin , context (archaeology) , chemistry , receptor , biology , biochemistry , paleontology
By acting on serotonin 5‐HT 2A receptors (5‐HT 2A Rs), serotonergic psychedelic drugs induce perceptual and visual hallucinations by increasing neuronal excitability and altering visual‐evoked neuronal responses. The present study was designed to examine whether the perceptual alterations induced by a serotonergic psychedelic drug would affect the integrity of hippocampal‐dependent, visually guided spatial cognition. phenylalkylamine hallucinogen TCB‐2 is a selective agonist of 5‐HT 2A Rs. Mice received TCB‐2 (1.0 mg kg −1 , i.p.), and spatial behaviors and hippocampal electrophysiological responses were measured with water maze tasks and in vivo single‐unit recording, respectively. TCB‐2 did not affect visual cue approach behavior in the visible platform water maze, but increased the latency of trained mice to initiate goal‐directed swimming during a probe test in the hidden platform Morris water maze, which could be prevented by 5‐HT 2A R antagonist MDL 11,939. Interestingly, TCB‐2 did not affect the efficiency of the swim path or the proper use of distal visual cues during the probe test. Hippocampal place cell activity is considered to represent spatial and context‐specific episodic memory. Systemic TCB‐2 did not affect previously established place fields of CA1 neurons in mice exploring a familiar environment, or the remapping of place cells when the mice explored a novel environment. However, TCB‐2 impaired the long‐term stability of place fields for the novel environment initially encoded under the influence of TCB‐2, which could be prevented by 5‐HT 2A R antagonist MDL 11,939. Our data indicate that hallucinogenic 5‐HT 2A R agonist delays the initiation of spatial search behavior, but does not impair the use of visual cues to guide goal‐directed spatial behavior. Moreover, activation of 5‐HT 2A Rs does not impair the coding and retrieval of spatial information, but impairs the long‐term stability of new formed place fields of CA1 neurons. © 2017 Wiley Periodicals, Inc.