Diverse modulation of olfactory bulb AMPA receptors by zinc.
Increasing evidence suggests that zinc modulates synaptic transmission in the olfactory bulb and other brain regions. We investigated the sensitivity of AMPA receptors on the bulb's two primary neuronal populations to several concentrations of zinc. Zinc (30-1000 microM) was coapplied to mitral/tufted cells and interneurons during AMPA-evoked currents, and current responses (potentiation, inhibition, no effect) were analyzed. Both neuronal populations expressed zinc-sensitive and zinc-insensitive AMPA receptors. However, the frequency and magnitude of zinc's effects varied with cell type. In addition, zinc did not always have biphasic effects at AMPA receptors (potentiation at low concentrations; inhibition at high concentrations), as reported in other brain regions. Zinc's diverse effects suggest that zinc may alter odor information processing by differential modulation of excitatory circuits.
Blakemore
Laura J
LJ
Department of Biological Science, Program in Neuroscience, Florida State University, Tallahassee, FL 32306-4340, USA. blakemore@neuro.fsu.edu
Trombley
Paul Q
PQ
D000818:Animals; D000831:Animals, Newborn; D002478:Cells, Cultured; D004305:Dose-Response Relationship, Drug; D004347:Drug Interactions; D018690:Excitatory Amino Acid Agonists / Q000494:pharmacology; D008564:Membrane Potentials / Q000187:drug effects; D009474:Neurons / Q000145:classification / Q000187:drug effects* / Q000378:metabolism; D009830:Olfactory Bulb / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D018408:Patch-Clamp Techniques / Q000379:methods; D051381:Rats; D018091:Receptors, AMPA / Q000378:metabolism*; D015032:Zinc / Q000494:pharmacology*; D018350:alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid / Q000494:pharmacology
D018690:Excitatory Amino Acid Agonists; D018091:Receptors, AMPA; D018350:alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid; D015032:Zinc