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Hippocampal ‘zipper’ slice studies reveal a necessary role for calcineurin in the increased activity of L-type Ca2+ channels with aging
- Source :
- Neurobiology of Aging. 31:328-338
- Publication Year :
- 2010
- Publisher :
- Elsevier BV, 2010.
-
Abstract
- Previous studies have shown that inhibition of the Ca(2+)-/calmodulin-dependent protein phosphatase calcineurin (CN) blocks L-type voltage sensitive Ca(2+) channel (L-VSCC) activity in cultured hippocampal neurons. However, it is not known whether CN contributes to the increase in hippocampal L-VSCC activity that occurs with aging in at least some mammalian species. It is also unclear whether CN's necessary role in VSCC activity is simply permissive or is directly enhancing. To resolve these questions, we used partially dissociated hippocampal "zipper" slices to conduct cell-attached patch recording and RT-PCR on largely intact single neurons from young-adult, mid-aged, and aged rats. Further, we tested for direct CN enhancement of L-VSCCs using virally mediated infection of cultured neurons with an activated form of CN. Similar to previous work, L-VSCC activity was elevated in CA1 neurons of mid-aged and aged rats relative to young adults. The CN inhibitor, FK-506 (5muM) completely blocked the aging-related increase in VSCC activity, reducing the activity level in aged rat neurons to that in younger rat neurons. However, aging was not associated with an increase in neuronal CN mRNA expression, nor was CN expression correlated with VSCC activity. Delivery of activated CN to primary hippocampal cultures induced an increase in neuronal L-VSCC activity but did not elevate L-VSCC protein levels. Together, the results provide the first evidence that CN activity, but not increased expression, plays a selective and necessary role in the aging-related increase in available L-VSCCs, possibly by direct activation. Thus, these studies point to altered CN function as a novel and potentially key factor in aging-dependent neuronal Ca(2+) dysregulation.
- Subjects :
- Male
Senescence
endocrine system
Aging
Patch-Clamp Techniques
Calcium Channels, L-Type
Blotting, Western
Calcineurin Inhibitors
Genetic Vectors
Phosphatase
Hippocampus
In Vitro Techniques
Biology
Hippocampal formation
Tacrolimus
Article
Adenoviridae
Membrane Potentials
Rats, Sprague-Dawley
Animals
L-type calcium channel
RNA, Messenger
Patch clamp
CA1 Region, Hippocampal
Cells, Cultured
Neurons
Membrane potential
Reverse Transcriptase Polymerase Chain Reaction
Calcineurin
General Neuroscience
Rats, Inbred F344
Rats
Cell biology
Biochemistry
Neurology (clinical)
Geriatrics and Gerontology
Central Nervous System Agents
Developmental Biology
Subjects
Details
- ISSN :
- 01974580
- Volume :
- 31
- Database :
- OpenAIRE
- Journal :
- Neurobiology of Aging
- Accession number :
- edsair.doi.dedup.....886a31b9e47540d9231ef5e3db13a426