Related Experiment Video
Updated: Mar 25, 2026

The Double-H Maze: A Robust Behavioral Test for Learning and Memory in Rodents
Published on: July 8, 2015
The Role of Hippocampal 5HT3 Receptors in Harmaline-Induced Memory Deficit
1Department of Biology, Faculty of Basic Sciences, Garmsar Branch, Islamic Azad University, Garmsar, Iran.
Introduction:
The plethora of studies indicated that there is a cross talk relationship between harmaline and serotonergic (5-HT) system on cognitive and non-cognitive behaviors. Thus, the purpose of this study is to assess the effects of hippocampal 5-HT4 receptor on memory acquisition deficit induced by harmaline.
Methods:
Harmaline was injected peritoneally, while 5-HT4 receptor agonist (RS67333) and antagonist (RS23597-190) were injected intra-hippocampal. A single-trial step-down passive avoidance, open field and tail flick tasks were used for measurement of memory, locomotor activity and pain responses, respectively.
Results:
The data revealed that pre-training injection of higher dose of harmaline (1 mg/kg), RS67333 (0.5 ng/mouse) and RS23597-190 (0.5 ng/mouse) decreased memory acquisition process in the adult mice. Moreover, concurrent pre-training administration of subthreshold dose of RS67333 (0.005 ng/mouse) or RS23597-190 (0.005 ng/mouse) with subthreshold dose of harmaline (0.5 mg/kg, i.p.) intensify impairment of memory acquisition. All above interventions did not change locomotion and tail flick behaviors.
Discussion:
The results demonstrated that the synergistic effect between both hippocampal 5-HT4 receptor agonist and antagonist with impairment of memory acquisition induced by harmaline, indicating a modulatory effect for hippocampal 5HT4 receptor on Harmaline induced amnesia.
Related Concept Videos
Role of Hippocampus in Memory
Role of Neurotransmitters in Memory
Glutamate and Synaptic Plasticity
Glutamate, the brain's main excitatory neurotransmitter, is...
Role of Amygdala in Memory
One of the...
Long-term Depression
Calcium Ion Concentration Mechanism
If over...
Long-term Depression
Higher Mental Functions of Brain: Learning and Memory

