Research Interests and Techniques

Ion channel proteins allow ions to pass through cell membranes and underlie many types of signalling within and between cells. We are interested in the properties and physiological functions of ion channels, especially those that are permeable to potassium ions in the cardiovascular system. In arterial smooth muscle, voltage-gated (Kv) and ATP-sensitive potassium channels (KATP) are critical regulators of arterial tone, controlling blood distribution and flow. Vasodilators activate, and vasoconstrictors inhibit these channels, and channel function is altered in many vascular diseases, and we are studying the ways in which these effects occur. In the heart, KATP channels serve to protect cardiac tissue during stress. They also form targets for drugs used to treat diabetes, angina, and hypertension. In cardiac muscle, we are interested in the way in which these channels cause protection. Current areas of research are:

• The regulation of arterial voltage-gated potassium channels by vasoconstrictors, vasodilators, and glucose, and its role in arterial function
• The protective roles of different cardiac KATP channel subunits investigated by RNA interference and overexpression
• Interrelationships between KATP channels, adenosine and protein kinases in protection of isolated cardiac myocytes, and in functional recovery after metabolic stress

Techniques

Methods that we currently use include the following:

• Patch clamp recording of currents flowing through ion channels, both from whole cells and from single channels
• Recombinant approaches to generate molecular constructs for the manipulation of channels and signalling pathways in native cells: dominant negatives, overexpression, RNA interference
• Fluorescent measurements of intracellular [Ca2+], ATP, NADH, mitochondrial membrane potential and other factors
• Imaging methods to detect location and movement of EGFP-tagged proteins and antibodies
  Measurements of contraction in cardiac and arterial muscle using optical methods and force transducer

Research Group and Funding

Present group members

Dr Jenny Brignell
Mr Andrew Chadburn
Mrs Diane Everitt
Dr Gavin Morris
Dr Carl Nelson
Mrs Fouzia Panhwar
Dr Nina Storey
Miss Helen Turrell

Current funding

British Heart Foundation Programme, BBSRC

Recent Publications

Rainbow RD, Standen NB and Davies NW. (2007). Endothelin and angiotensin II inhibit arterial voltage-gated K+ channels through different PKC isoenzymes. Biophys. J. supplement. 588-Pos/B433.

Storey NM, Lodwick D and Standen NB. (2007). Using RNAi to investigate roles of KATP channel subunits in cardiac protection. Biophys. J. supplement 2961-Pos/B325.

Rainbow RD, Hardy MEL, Standen NB and Davies NW. (2006). Glucose reduces endothelin inhibition of voltage-gated potassium channels in rat arterial smooth muscle cells. J. Physiol. 575, 833-844.

Hardy MEL, Lawrence CL, Standen NB and Rodrigo GC. (2006). Can optical recordings of membrane potential be used to screen for drug-induced action potential prolongation in single cardiac myocytes? J. Pharmacological. Toxicol. Methods. 54, 173-182.

Rodrigo GC and Standen NB. (2005). Role of mitochondrial re-energization and Ca 2+ influx in reperfusion injury of metabolically inhibited cardiac myocytes. Cardiovasc. Res. 67, 291-300.

Rodrigo GC and Standen NB. (2005). ATP-sensitive potassium channels. Current Pharmaceutical Design 11, 1915-1940.

Sampson LJ, Hayabuchi Y, Standen NB and Dart C. (2004). Caveolae localise protein kinase A signalling to arterial ATP-sensitive potassium channels. Circ. Res. 95, 1012-1018.

Rainbow RD, Lodwick D, Hudman D, Davies NW, Norman RI and Standen NB. (2004). SUR2A C-terminal fragments reduce K ATP currents and ischaemic tolerance of rat cardiac myocytes. J. Physiol. 557, 785-794.

Rodrigo GC, Davies NW and Standen NB. (2004). Diazoxide causes early activation of cardiac sarcolemmal K ATP channels during metabolic inhibition by an indirect mechanism. Cardiovasc. Res. 61, 570-579.

Lippiat JD, Standen NB and Davies NW. (2003). Properties of BK Ca channels formed by bicistronic expression of hSlo a and b 1-4 subunits in HEK293 cells. Journal of Membrane Biology 192, 141-148.

Lawrence CL, Rainbow RD, Davies NW and Standen NB. (2002). Effect of metabolic inhibition on glimepiride block of native and cloned cardiac sarcolemmal K ATP channels. Br. J. Pharmacol. 136, 746-752.

Rodrigo GC, Lawrence CL and Standen NB. (2002). Dinitrophenol pretreatment of rat ventricular myocytes protects against damage by metabolic inhibition and reperfusion. J. Mol. Cell. Cardiol. 34, 555-569.

Hayabuchi Y, Dart C and Standen NB. (2001). Evidence for involvement of A-kinase anchoring protein in activation of rat arterial K ATP channels by protein kinase A. J. Physiol. 536, 421-427.

Lawrence CL, Billups B, Rodrigo GC and Standen NB. (2001). The K ATP channel opener diazoxide protects cardiac myocytes during metabolic inhibition without causing mitochondrial depolarization or flavoprotein oxidation. Br. J. Pharmacol. 134, 535-542.

Hayabuchi Y, Davies NW and Standen NB. (2001). Angiotensin II inhibits rat arterial K ATP channels by inhibiting steady-state PKA activity and activating PKCe. J. Physiol. 530, 193-205.

Lawrence CL, Proks P, Rodrigo GC, Jones P, Hayabuchi Y, Standen NB and Ashcroft FM. (2001). Gliclazide produces high affinity block of K ATP channels in mouse isolated pancreatic b -cells but not rat heart or arterial smooth muscle cells. Diabetologia 44, 1019-1025.

Mocanu MM, Maddock HL, Baxter GF, Lawrence CL, Standen NB and Yellon DM. (2001). Glimepiride, a novel sulphonylurea, does not abolish myocardial protection afforded by either preconditioning or diazoxide. Circulation 103, 3111-3116.

Ghosh S, Standen NB and Galiñanes M. (2001). Failure to precondition pathological human myocardium. J. Am. Coll. Cardiol. 37, 711-718.