The serotonergic modulation of synaptic plasticity in the rat hippocampo-medial prefrontal cortex pathway.
The ability of the serotonergic (5-HTergic) system to affect the hippocampo-medial prefrontal cortex (mPFC) synaptic properties was examined in rats with lesions of 5-HTergic neurons. Intracerebroventricular injections of 5,7-dihydroxytryptamine (5,7-DHT) resulted in selective depletion of 5-HT and 5-hydroxyindoleacetic acid in the cerebral cortex, hippocampus and raphe regions. The 5,7-DHT-lesioned rat had no changes in basal synaptic transmission in the hippocampo-mPFC pathway. Conversely, we observed the augmentation of short-term synaptic plasticity, i.e. paired-pulse facilitation, when compared with sham-operated rats in this pathway. The magnitude of long-term potentiation (LTP) was significantly augmented in 5,7-DHT-lesioned rats. This augmentation of hippocampo-mPFC LTP had a significant correlation with the degree of cortical 5-HT levels. These results suggest that the 5-HTergic system may modulate plastic properties at the hippocampal-mPFC synapses in vivo.
Ohashi
Satoshi
S
Department of Pharmacology, Hokkaido University Graduate School of Medicine, Kita-15, Nishi-7, Kita-ku, 060-8638, Sapporo, Japan.
Matsumoto
Machiko
M
Togashi
Hiroko
H
Ueno
Ken-ichi
K
Yoshioka
Mitsuhiro
M
D015116:5,7-Dihydroxytryptamine / Q000633:toxicity; D000818:Animals; D019540:Area Under Curve; D004558:Electric Stimulation; D005071:Evoked Potentials / Q000502:physiology; D006624:Hippocampus / Q000502:physiology*; D007276:Injections, Intraventricular / Q000379:methods; D008297:Male; D009434:Neural Pathways / Q000502:physiology*; D009473:Neuronal Plasticity / Q000502:physiology*; D017397:Prefrontal Cortex / Q000502:physiology*; D051381:Rats; D017208:Rats, Wistar; D012701:Serotonin / Q000032:analysis / Q000378:metabolism*; D018490:Serotonin Agents / Q000633:toxicity; D009435:Synaptic Transmission
D018490:Serotonin Agents; D015116:5,7-Dihydroxytryptamine; D012701:Serotonin