Long-lasting potentiation and depression by novel isoproterenol and cholecystokinin 8-S interactions in the dentate gyrus.
In the in vitro hippocampal slice, novel interactions of a beta-adrenergic agonist (l-isoproterenol) and neuropeptide (cholecystokinin 8-S) differentially produce long-lasting modifications in the dentate gyrus. When co-applied, a low concentration of l-isoproterenol (50-75 nM) and cholecystokinin 8-S (1.0 microM) produce long-lasting depression of evoked action potentials (i.e., population spikes). In contrast, the same concentration of l-isoproterenol followed by a 30-min wash with artificial cerebrospinal fluid and application of cholecystokinin 8-S produces long-lasting potentiation of evoked action potentials. In neither condition are there corresponding modifications of excitatory post-synaptic potentials. These results indicate that l-isoproterenol and cholecystokinin 8-S temporally interact to differentially produce depression or potentiation of granule cell-activation In contrast to long-lasting modifications produced by continuous application of 1.0 microM l-iso-proterenol, in which both evoked action potentials and excitatory post-synaptic potentials are affected, the present novel paradigm may modify an extra-synaptic locus.
Dahl
D
D
School of Human Development, University of Texas at Dallas, Richardson 75080.
Li
J
J
D000818:Animals; D001418:Baclofen / Q000494:pharmacology; D004357:Drug Synergism; D004558:Electric Stimulation; D005071:Evoked Potentials / Q000187:drug effects / Q000502:physiology; D006624:Hippocampus / Q000187:drug effects*; D066298:In Vitro Techniques; D007545:Isoproterenol / Q000494:pharmacology*; D017774:Long-Term Potentiation / Q000187:drug effects; D008297:Male; D009473:Neuronal Plasticity / Q000187:drug effects*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012844:Sincalide / Q000031:analogs & derivatives* / Q000494:pharmacology
C044201:cholecystokinin (26-33); D001418:Baclofen; D007545:Isoproterenol; D012844:Sincalide