Measurement of presynaptic zinc changes in hippocampal mossy fibers

• Published in: Brain research 2004-11, Vol.1026 (1), p.1-10
• Main Authors: Quinta-Ferreira, M.E., Matias, C.M., Arif, M., Dionísio, J.C.
• Format: Article
• Language: English
• Subjects: 2-Amino-5-phosphonovalerate - pharmacology; 6-Cyano-7-nitroquinoxaline-2,3-dione - pharmacology; Aminoquinolines - pharmacokinetics; Animals; Anticonvulsants - pharmacology; Biological and medical sciences; CA3 area; Central nervous system; Cholinesterase Inhibitors - pharmacology; Cyclopropanes - pharmacology; Dose-Response Relationship, Radiation; Drug Interactions; Electric Stimulation - methods; Electrophysiology; Ethylenediamines - pharmacology; Excitatory Amino Acid Antagonists - pharmacology; Fluorescent Dyes - pharmacokinetics; Fundamental and applied biological sciences. Psychology; GABA Antagonists - pharmacology; Glutamate; Glycine - analogs & derivatives; Glycine - pharmacology; In Vitro Techniques; Long-term potentiation; Long-Term Potentiation - drug effects; Long-Term Potentiation - physiology; Long-Term Potentiation - radiation effects; Mossy fiber synapse; Mossy Fibers, Hippocampal - drug effects; Mossy Fibers, Hippocampal - metabolism; Mossy Fibers, Hippocampal - radiation effects; Paired-pulse facilitation; Picrotoxin - pharmacology; Rats; Rats, Inbred WF; Synapses - drug effects; Synapses - metabolism; Synapses - radiation effects; Time Factors; Tosyl Compounds - pharmacokinetics; TPEN; TSQ; Vertebrates: nervous system and sense organs; Zinc - metabolism
• ISSN: 0006-8993; 1872-6240
• DOI: 10.1016/j.brainres.2004.07.054

The hippocampal mossy fiber terminals of CA3 area contain high levels of vesicular zinc that is released in a calcium-dependent way, following high-frequency stimulation. However the properties of zinc release during normal synaptic transmission, paired-pulse facilitation and mossy fiber long-term potentiation are still unknown. Using the fluorescent zinc probe N-(6-methoxy-8-quinolyl)- para-toluenesulfonamide, we measured fast mossy fiber zinc changes indicating that zinc is released following single and low levels of electrical stimulation. The observed presynaptic zinc signals are maintained during the expression of mossy fiber long-term potentiation, assumed to be mediated by an increase in transmitter release, and are enhanced during paired-pulse facilitation. This zinc enhancement is, like paired-pulse facilitation, reduced during established long-term potentiation. The correlation between the paired-pulse evoked zinc and field potential responses supports the idea that zinc is co-released with glutamate.