The 5-HT4 receptor levels in hippocampus correlates inversely with memory test performance in humans.
The cerebral serotonin (5-HT) system is involved in cognitive functions such as memory and learning and animal studies have repeatedly shown that stimulation of the 5-HT type 4 receptor (5-HT4 R) facilitates memory and learning and further that the 5-HT4 R modulates cellular memory processes in hippocampus. However, any associations between memory functions and the expression of the 5-HT4 R in the human hippocampus have not been investigated. Using positron emission tomography with the tracer [(11) C]SB207145 and Reys Auditory Verbal Learning Test we aimed to examine the individual variation of the 5-HT4R binding in hippocampus in relation to memory acquisition and consolidation in healthy young volunteers. We found significant, negative associations between the immediate recall scores and left and right hippocampal BPND , (p = 0.009 and p = 0.010 respectively) and between the right hippocampal BPND and delayed recall (p = 0.014). These findings provide evidence that the 5-HT4 R is associated with memory functions in the human hippocampus and potentially pharmacological stimulation of the receptor may improve episodic memory.
Neurobiology Research Unit and Center of Integrated Molecular Brain Imaging, University Hospital Rigshospitalet, 24 Juliane Maries Vej, 2100 Copenhagen, Denmark; Danish Research Centre for Magnetic Resonance, University Hospital Hvidovre, 30 Kettegård Allé, 2650 Hvidovre, Denmark.
Mette Ewers
ME
Haahr
Patrick
P
Fisher
Klaus
K
Holst
Karine
K
Madsen
Christian Gaden
CG
Jensen
Lisbeth
L
Marner
Szabols
S
Lehel
William
W
Baaré
Gitte
G
Knudsen
Steen
S
Hasselbalch
D000328:Adult; D000465:Algorithms; D001931:Brain Mapping; D003627:Data Interpretation, Statistical; D005260:Female; D007839:Functional Laterality / Q000502:physiology; D006624:Hippocampus / Q000033:anatomy & histology* / Q000000981:diagnostic imaging / Q000378:metabolism*; D006801:Humans; D007091:Image Processing, Computer-Assisted; D007858:Learning / Q000502:physiology; D008279:Magnetic Resonance Imaging; D008297:Male; D061212:Memory, Episodic; D011939:Mental Recall / Q000502:physiology; D009483:Neuropsychological Tests; D049268:Positron-Emission Tomography; D011597:Psychomotor Performance / Q000502:physiology*; D044422:Receptors, Serotonin, 5-HT4 / Q000378:metabolism*; D014706:Verbal Learning / Q000502:physiology; D055815:Young Adult
D044422:Receptors, Serotonin, 5-HT4