Locus coeruleus stimulation and noradrenergic modulation of hippocampo-prefrontal cortex long-term potentiation.
Stimulation of the subiculum/CA1 of the hippocampal formation evokes monosynaptic field potentials in the prefrontal cortex (PFC). High-frequency stimulation of the hippocampus (HPC) can induce long-term potentiation (LTP) in this hippocampo-prefrontal cortical (hippo-PFC) pathway. Previous studies have shown that dopamine and serotonin modulate hippo-PFC LTP. Here, we investigated whether the locus coeruleus (LC) and noradrenaline (NA) can modulate LTP in the rat hippo-PFC pathway. Stimulation of the LC in combination with stimulation of the HPC increased hippo-PFC LTP. Infusion of lidocaine into the LC reduced hippo-PFC LTP. Administration of the noradrenaline reuptake inhibitor, nisoxetine or the alpha2 adrenoceptor antagonist, idazoxan prior to high-frequency stimulation of the HPC enhanced hippo-LTP. In contrast, administration of clonidine, an alpha2 adrenoceptor agonist, impaired hippo-PFC LTP. Partial noradrenergic (NAergic) lesioning with DSP-4 also impaired hippo-PFC LTP. In conclusion, the LC and NAergic mechanisms modulate hippo-PFC LTP.
Department of Pharmacology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore.
Ee Peng
EP
Lim
Chay Hoon
CH
Tan
Thérèse M
TM
Jay
Gavin S
GS
Dawe
D018663:Adrenergic Agents / Q000378:metabolism / Q000494:pharmacology; D058669:Adrenergic alpha-2 Receptor Antagonists / Q000378:metabolism / Q000494:pharmacology; D000316:Adrenergic alpha-Agonists / Q000378:metabolism / Q000494:pharmacology; D000818:Animals; D001596:Benzylamines / Q000378:metabolism / Q000494:pharmacology; D003000:Clonidine / Q000378:metabolism / Q000494:pharmacology; D004298:Dopamine / Q000378:metabolism / Q000502:physiology; D006624:Hippocampus / Q000187:drug effects* / Q000378:metabolism / Q000502:physiology; D019329:Idazoxan / Q000378:metabolism / Q000494:pharmacology; D008125:Locus Coeruleus / Q000187:drug effects* / Q000502:physiology; D017774:Long-Term Potentiation / Q000187:drug effects; D008297:Male; D009638:Norepinephrine / Q000378:metabolism*; D017397:Prefrontal Cortex / Q000187:drug effects* / Q000378:metabolism* / Q000502:physiology; D051381:Rats; D017207:Rats, Sprague-Dawley; D012701:Serotonin / Q000378:metabolism / Q000502:physiology
D018663:Adrenergic Agents; D058669:Adrenergic alpha-2 Receptor Antagonists; D000316:Adrenergic alpha-Agonists; D001596:Benzylamines; D012701:Serotonin; D003000:Clonidine; C012102:DSP 4; D004298:Dopamine; D009638:Norepinephrine; D019329:Idazoxan