title: Vinpocetine regulates cation channel permeability of inner retinal neurons in the ischaemic retina.
abstract: Vinpocetine is a natural drug which exerts neuroprotective effects in ischaemia of the brain through actions on cation channels, glutamate receptors and other pathways. This study investigated the effect of vinpocetine on cation channel permeability of inner retinal neurons after acute retinal metabolic insult. We focused on amacrine and ganglion cells immunoreactive for calretinin or parvalbumin due to their previously documented susceptibility to ischaemia. Using the probe, 1-amino-4-guanidobutane (AGB), we observed increased cation channel permeability across amacrine and ganglion cells under ischaemia and hypoglycaemia but not anoxia. Calretinin and parvalbumin immunoreactivity was also reduced during ischaemia and hypoglyacemia but not anoxia. Vinpocetine decreased AGB entry into ischaemic and hypoglycaemic ganglion cells indicating that the drug can modulate unregulated cation entry. In addition, vinpocetine prevented the loss of calretinin and parvalbumin immunoreactivity following ischaemia suggesting it may indirectly regulate intracellular calcium. Vinpocetine also reduced AGB permeability in selected amacrine and ganglion cell populations following N-methyl-D-aspartate (NMDA) but not kainate activation suggesting that vinpocetine's regulation of cation channel permeability may partly involve NMDA sensitive glutamate receptors.
authors.affiliation: School of Optometry and Vision Science, University of New South Wales, Sydney 2052, Australia.
authors.forename: Lisa
authors.initials: L
authors.lastname: Nivison-Smith
authors.affiliation: Department of Optometry and Vision Science, University of Auckland, Auckland, New Zealand; New Zealand National Eye Centre, University of Auckland, Auckland, New Zealand.
authors.forename: Monica L
authors.initials: ML
authors.lastname: Acosta
authors.affiliation: Department of Optometry and Vision Science, University of Auckland, Auckland, New Zealand; New Zealand National Eye Centre, University of Auckland, Auckland, New Zealand; Department of Ophthalmology, University of Auckland, Auckland, New Zealand.
authors.forename: Stuti
authors.initials: S
authors.lastname: Misra
authors.affiliation: Department of Optometry and Vision Science, University of Auckland, Auckland, New Zealand.
authors.forename: Brendan J
authors.initials: BJ
authors.lastname: O'Brien
authors.affiliation: School of Optometry and Vision Science, University of New South Wales, Sydney 2052, Australia; Centre for Eye Health, University of New South Wales, Sydney 2052, Australia; Department of Optometry and Vision Science, University of Auckland, Auckland, New Zealand; New Zealand National Eye Centre, University of Auckland, Auckland, New Zealand. Electronic address: m.kalloniatis@unsw.edu.au.
authors.forename: Michael
authors.initials: M
authors.lastname: Kalloniatis
mesh_terms: D000376:Agmatine / Q000378:metabolism; D000818:Animals; D002121:Calcium Channel Blockers / Q000494:pharmacology / Q000627:therapeutic use; D007473:Ion Channels / Q000378:metabolism*; D007511:Ischemia / Q000188:drug therapy / Q000378:metabolism*; D009924:Organ Culture Techniques; D010539:Permeability / Q000187:drug effects; D051381:Rats; D017207:Rats, Sprague-Dawley; D016194:Receptors, N-Methyl-D-Aspartate / Q000378:metabolism; D012160:Retina / Q000187:drug effects / Q000378:metabolism; D055351:Retinal Neurons / Q000187:drug effects* / Q000378:metabolism*; D014748:Vinca Alkaloids / Q000494:pharmacology* / Q000627:therapeutic use
chemical_list: D002121:Calcium Channel Blockers; D007473:Ion Channels; D016194:Receptors, N-Methyl-D-Aspartate; D014748:Vinca Alkaloids; C013983:vinpocetine; D000376:Agmatine
keywords: Agmatine; Cation channel; Ischaemia; Retina; Vinpocetine