The opioid peptide dynorphin mediates heterosynaptic depression of hippocampal mossy fibre synapses and modulates long-term potentiation.
The mossy fibre pathway in the hippocampus uses glutamate as a neurotransmitter, but also contains the opioid peptide dynorphin. Synaptic release of dynorphin causes a presynaptic inhibition of neighbouring mossy fibres and inhibits the induction and expression of mossy fibre long-term potentiation. These findings demonstrate a physiological role for a neuropeptide in the central nervous system, provide a functional basis for the coexistence of a neuropeptide with classic neurotransmitters and demonstrate the very different roles played by these two classes of signalling molecules.
Weisskopf
M G
MG
Neuroscience Graduate Program, University of California, San Francisco 94143-0450.
Zalutsky
R A
RA
Nicoll
R A
RA
D018750:6-Cyano-7-nitroquinoxaline-2,3-dione; D000818:Animals; D004558:Electric Stimulation; D005071:Evoked Potentials / Q000187:drug effects; D018691:Excitatory Amino Acid Antagonists; D006168:Guinea Pigs; D006624:Hippocampus / Q000187:drug effects / Q000502:physiology*; D066298:In Vitro Techniques; D009270:Naloxone / Q000494:pharmacology; D009412:Nerve Fibers / Q000187:drug effects / Q000502:physiology; D011712:Pyramidal Tracts / Q000187:drug effects / Q000502:physiology*; D011810:Quinoxalines / Q000494:pharmacology; D017473:Receptors, Opioid, kappa / Q000187:drug effects / Q000502:physiology; D013569:Synapses / Q000187:drug effects / Q000502:physiology*
D018691:Excitatory Amino Acid Antagonists; D011810:Quinoxalines; D017473:Receptors, Opioid, kappa; D009270:Naloxone; D018750:6-Cyano-7-nitroquinoxaline-2,3-dione