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Senior Scientist, Neuroscience, Ottawa Hospital Research Institute
Ph.D. 1977 University of Cambridge, England
B.Sc. Hons. 1973 University of Canterbury, Christchurch, New Zealand
Full Professor, Department of Medicine, Division of Neurology, University of Ottawa
Research Interests
Mechanosensitive ion channels
Mechanosensitive cell surface area regulation
Major Research Activities
Many ion channels respond to membrane stretch by changing their open probability. In principle, this mechanosusceptibility can be an asset that allows cells to monitor their mechanical status, or a liability that generates unwanted crosstalk. Dr Morris, is currently studying the mechanosusceptibility of voltage-gated ion channels, whose principal responsibility is for electrical excitability. Most, it now appears, respond to stretch in one way or another.
Of particular physiological interest are the voltage-gated calcium channels, which have been shown to produce mechano-currents in vascular smooth muscle and neurosecretory cells.
Of particular biophysical interest are Shaker potassium channels, best-understood of all the voltage-gated channels.
Of particular pathological interest are the "hyperexcitable" voltage-gated sodium channels, since unwanted stretch activation of these channels may contribute to the runaway ion fluxes of damaged neurons.
Of particular evolutionary interest is CCH1, a putative channel from yeast. When yeast cells swell, CCH1 mediates a calcium influx. The amino acid sequence of CCH1 classifies it as related to voltage-gated calcium and sodium channels.
Dr Morris' lab uses recombinant channels, patch clamp electrophysiology, and molecular biology to study exemplars from each of these categories.
Additionally, Dr Morris studies surface area regulation in neurons. Because neurons are designed to convey electrical signals at high speed it behooves them to operate without excess membrane; every extra bit of bilayer slows the speed and increases the metabolic cost of signalling. However, having minimized bilayer area, neurons must be able to rapidly recruit additional surface area whenever and wherever bilayer tension increases or the membrane would rupture. Dr Morris' lab studies how the balance is struck between too much and too little surface area, with the emphasis on the role of membrane tension as a signal. Confocal microscopy is used to study bilayer and membrane skeleton dynamics in shrinking and swelling neurons.
Grants
2000-05 NSERC Channels, membranes and cell mechanics
2000-03 HSFO Surface area regulation: sublethal ischemia and neuronal repair
(co-investigator, L Mills, Toronto).
2001-04 CIHR Mechanosensitivity of Ca channels
Most Recent Publications (provided by The Ottawa Hospital Library Database)
Morris CE, Juranka PF (2007) Lipid stress at play: mechanosensitivity of voltage-gated channels.
Current Topics in Membranes 59: 297-337
Banderali U;Juranka PF;Clark RB;Giles WR;Morris CE;, (2010 Jan 6), Impaired stretch modulation in potentially lethal cardiac sodium channel mutants, Channels (Austin), Vol.4, Issue 1, -> view abstract
Wang JA;Lin W;Morris T;Banderali U;Juranka PF;Morris CE;, (2009 Oct), Membrane trauma and Na+ leak from Nav1.6 channels, Am J Physiol Cell Physiol, Vol.297, Issue 4, C823 -> view abstract
Boucher PA;Morris CE;Joos B;, (2009 Nov 18), Mechanosensitive closed-closed transitions in large membrane proteins: osmoprotection and tension damping, Biophys J, Vol.97, Issue 10, 2761-2770 -> view abstract
Welch NC;Lin W;Juranka PF;Morris CE;Stys PK;, (2008 Dec), Traditional AMPA receptor antagonists partially block Na v1.6-mediated persistent current, Neuropharmacology, Vol.55, Issue 7, 1165-1171 -> view abstract
Lin W;Laitko U;Juranka PF;Morris CE;, (2007 Mar 1), Dual stretch responses of mHCN2 pacemaker channels: accelerated activation, accelerated deactivation, Biophys J, Vol.92, Issue 5, 1559-1572 -> view abstract
Morris CE;Juranka PF;, (2007 Aug 1), Nav channel mechanosensitivity: activation and inactivation accelerate reversibly with stretch, Biophysical Journal, Vol.93, Issue 3, 822-833
Morris CE;Juranka PF;, (2007), Lipid stress at play: mechanosensitivity of voltage-gated channels. Current Topics in Membranes 59: 297-337, Current Topics in Membranes, Vol.59, 297-337
Laitko U;Juranka PF;Morris CE;, (2006 Jun), Membrane Stretch Slows the Concerted Step prior to Opening in a Kv Channel, J Gen Physiol, Vol.127, Issue 6, 687-701 -> view abstract
Morris CE;Juranka PF;Lin W;Morris TJ;Laitko U;, (2006), Studying the mechanosensitivity of voltage-gated channels using oocyte patches, Methods Mol Biol, Vol.322, 315-329 -> view abstract
Laitko U;Morris CE;, (2004 Feb), Membrane tension accelerates rate-limiting voltage-dependent activation and slow inactivation steps in a Shaker channel, J Gen Physiol, Vol.123, Issue 2, 135-154 -> view abstract
Note: This is not a complete list of publications. More publications may be available in The Ottawa Hospital Library database and Pubmed (search by last name and initials).
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Roger Guindon Hall
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