NZ scientific breakthrough: Heart rate regulator ion channel discovered

AgResearch scientists, working with Victoria University and a scientist in the USA, have discovered that calcium-activated-potassium ion channels, present in only small amounts in the heart, have a significant role in modulating heart rate. The finding, once better understood, may open the way to pharmacological treatment for hypertension and for heart rate control during surgery.

This finding is controversial and significant as it is contrary to current thinking, with current opinion being that calcium-activated potassium (BK) ion channels are not directly involved in heart rate regulation.

Science publication PLoS One is publishing the New Zealand breakthrough results on Thursday 14 January 2010 (EST).

The team of scientists working in New Zealand and the USA made this breakthrough by using mice lacking BK channels (provided by Assistant Prof. Dr Andrea Meredith, now at the University of Maryland School of Medicine) and novel ion channel inhibitory compounds isolated and tested by Drs Dalziel and Finch. Former AgResearch supervised PhD student Wendy Imlach (currently at Columbia University Medical Center) conducted key experiments with Dr Meredith at Stanford University and further investigated the finding in collaboration with Prof. John H. Miller (Victoria University, Wellington). These experiments implicated the heart as being directly involved.

“We’re clearly excited by this discovery, and it’s fantastic to be involved with something that may pave the way for new heart drugs that act in a completely different way from those currently available. Up until now BK ion channels weren’t seen as a factor in modulating heart rate and had been overlooked by scientists” said AgResearch Scientist, Dr Julie Dalziel.

“The results in our study support the hypothesis that BK channels are expressed and functional in the heart. Their tissue location and role in cellular excitability remain to be determined,” said Dr Sarah Finch of AgResearch.

The research was funded by a grant from the Marsden Fund, administered by the Royal Society of New Zealand.

ENDS