Actions of zinc at mature Golgi cell to granule cell synapses in cerebellum of rats and mice.
A recent study has shown that cerebellar GABAergic interneuron (Golgi cell) terminals contain the zinc transporter znt3, raising the possibility that zinc is synaptically released to modulate GABAergic transmission. To test this possibility, the actions of exogenous zinc on Golgi cell to granule cell synaptic transmission were investigated and then the effects of removing endogenous zinc were examined. Application of zinc markedly reduced the tonic GABA(A)-receptor-mediated current in granule cells but produced a much smaller heterogeneous inhibitory effect on evoked phasic GABAergic currents. Neither the tonic current, single evoked synaptic currents nor trains of synaptic currents were modulated when endogenous zinc was chelated. Thus, there is no physiological evidence that zinc is released from Golgi cells to modulate GABAergic transmission.
Neuroscience Group, Department of Biological Sciences, University of Warwick, Coventry CV4 7AL, UK. mwall@bio.warwick.ac.uk
Mark J
MJ
Wall
D000818:Animals; D000831:Animals, Newborn; D001640:Bicuculline / Q000494:pharmacology; D002452:Cell Count / Q000379:methods; D002531:Cerebellum / Q000166:cytology*; D002614:Chelating Agents / Q000494:pharmacology; D004558:Electric Stimulation / Q000379:methods; D005029:Ethylenediamines / Q000494:pharmacology; D018756:GABA Antagonists / Q000494:pharmacology; D066298:In Vitro Techniques; D008297:Male; D008564:Membrane Potentials / Q000187:drug effects; D051379:Mice; D008807:Mice, Inbred BALB C; D009433:Neural Inhibition / Q000187:drug effects / Q000528:radiation effects; D009474:Neurons / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism / Q000528:radiation effects; D018408:Patch-Clamp Techniques / Q000379:methods; D051381:Rats; D017208:Rats, Wistar; D013569:Synapses / Q000187:drug effects* / Q000528:radiation effects; D015032:Zinc / Q000494:pharmacology*; D005680:gamma-Aminobutyric Acid / Q000378:metabolism*
D002614:Chelating Agents; D005029:Ethylenediamines; D018756:GABA Antagonists; D005680:gamma-Aminobutyric Acid; D015032:Zinc; C044387:N,N,N',N'-tetrakis(2-pyridylmethyl)ethylenediamine; D001640:Bicuculline