Dopamine selectively potentiates hippocampal mossy fiber to CA3 synaptic transmission.
Dopamine has been implicated in various brain functions and the pathology of neurological diseases. In the hippocampus, dopamine has been shown to induce acute depression of synaptic transmission in the CA1 region, but it remains largely unknown how it works in the CA3 region. We here report that dopamine induces acute synaptic potentiation at the synapse formed by mossy fibers (MFs) on mouse hippocampal CA3 pyramidal cells, but not at converging associational/commissural synapses. Dopamine potentiated both alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) and N-methyl-d-aspartate (NMDA) components of MF synaptic responses similarly in respect of the magnitude and time course. The dopamine-induced potentiation was intact in the presence of picrotoxin, required activation of D(1)-like receptors and was apparently occluded by an activator of adenylate cyclase. The potentiation was accompanied by a decrease in magnitude of synaptic facilitation, suggesting the presynaptic site for the expression of the potentiation. The present study is the first demonstration of acute potentiation of hippocampal excitatory synaptic transmission by dopamine, which is most probably mediated by presynaptic D(1)-like receptor-cAMP cascades.
Kobayashi
Katsunori
K
Department of Pharmacology, Nippon Medical School, 1-1-5 Sendagi, Bunkyo-ku, Tokyo 113-8602, Japan. kkatsu-tky@umin.ac.jp
Suzuki
Hidenori
H
D018750:6-Cyano-7-nitroquinoxaline-2,3-dione / Q000494:pharmacology; D000225:Adenine / Q000031:analogs & derivatives / Q000494:pharmacology; D000818:Animals; D004298:Dopamine / Q000494:pharmacology*; D018491:Dopamine Agonists / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D004558:Electric Stimulation; D004791:Enzyme Inhibitors / Q000494:pharmacology; D018691:Excitatory Amino Acid Antagonists / Q000494:pharmacology; D019706:Excitatory Postsynaptic Potentials / Q000187:drug effects / Q000502:physiology / Q000528:radiation effects; D006624:Hippocampus / Q000166:cytology*; D066298:In Vitro Techniques; D008297:Male; D051379:Mice; D019599:Mossy Fibers, Hippocampal / Q000187:drug effects*; D018408:Patch-Clamp Techniques / Q000379:methods; D017966:Pyramidal Cells / Q000187:drug effects* / Q000502:physiology / Q000528:radiation effects; D009435:Synaptic Transmission / Q000187:drug effects* / Q000502:physiology
D018491:Dopamine Agonists; D004791:Enzyme Inhibitors; D018691:Excitatory Amino Acid Antagonists; C017759:9-(tetrahydro-2-furyl)-adenine; D018750:6-Cyano-7-nitroquinoxaline-2,3-dione; D000225:Adenine; D004298:Dopamine