Zinc induces hyperexcitability in the hippocampus.
The effects of zinc on neuronal excitability in rodent hippocampal slices were examined. In a paired-pulse protocol, the second population spike increased appreciably in the presence of zinc, whereas the first spike and the size of both population excitatory post-synaptic potentials remained unaffected. Changes in the second population spike produced by zinc were most pronounced when the afferents were stimulated with paired-pulses separated by 8-40 ms. The magnitude of altered excitability increased with the concentration of zinc in the perfusate. A long exposure to zinc in physiological concentration caused an epileptiform discharge followed by a period of depression. The effects of zinc could be mimicked with 1-3 microM bicuculline. We conclude that the integrity of the hippocampal inhibitory system is particularly vulnerable to zinc.
Reece
L J
LJ
Department of Chemistry, Australian National University, Canberra.
Dhanjal
S S
SS
Chung
S H
SH
D000200:Action Potentials / Q000187:drug effects; D000818:Animals; D004558:Electric Stimulation / Q000379:methods; D004594:Electrophysiology; D004827:Epilepsy / Q000139:chemically induced / Q000503:physiopathology; D006624:Hippocampus / Q000187:drug effects* / Q000503:physiopathology*; D066298:In Vitro Techniques; D051379:Mice; D008808:Mice, Inbred CBA; D051381:Rats; D017208:Rats, Wistar; D015032:Zinc / Q000494:pharmacology*
D015032:Zinc