Related Experiment Video
Updated: Aug 14, 2026

An Appetitive Spatial Working Memory Task for Mice in a Semi-Automated 8-Arm Radial Maze, Reducing Fearful Memory Association in the Maze
Published on: July 29, 2025
Histamine ameliorates spatial memory deficits induced by MK-801 infusion into ventral hippocampus as evaluated by
Li-Sha Xu1, Li-Xia Yang, Wei-Wei Hu
1Department of Pharmacology, School of Medicine, Zhejiang University, Hangzhou 310031, China.
Aim:
To investigate the role of histamine in memory deficits induced by MK-801 infusion into the ventral hippocampus in rats.
Methods:
An 8-arm radial maze (4 arms baited) was used to assess spatial memory.
Results:
Bilateral ventral intrahippocampal (ih) infusion of MK-801 (0.3 microg/site), an N-methyl-D-aspartate (NMDA) antagonist, impaired the retrieval process in both working memory and reference memory. Intrahippocampal injection of histamine (25 or 50 ng/site) or intraperitoneal (ip) injection of histidine (25, 50 or 100 mg/kg) markedly ameliorated the spatial memory deficits induced by MK-801. Both the histamine H1 antagonist pyrilamine (0.5 or 1.0 microg/site, ih) and the H2 antagonist cimetidine (2.5 microg/site, ih) abolished the ameliorating effect of histidine (100 mg/kg, ip) on reference memory deficits, but not that on working memory deficits induced by MK-801.
Conclusion:
The results indicate that histamine in the ventral hippocampus can ameliorate MK-801-induced spatial memory deficits, and that histamine's effect on reference memory is mediated by postsynaptic histamine H1 and H2 receptors.

