Professor Ian Gibbins, Anatomy & Histology, Flinders University, South Australia.
Sympathetic neurons lie outside the blood brain barrier and are exposed to a wide range of circulating agents that can affect their excitability. We have been using single-molecule optical tracking techniques to directly measure the diffusion of angiotensin II and substance P through the extracellular space of the ganglia and then observe peptides binding to their receptors on intact neurons. Using high-speed confocal scanning and photon-counting detectors, we achieve a temporal resolution of 0.5µs and a spatial resolution of 0.15fl. Our data show that the kinetics of receptor binding are strongly limited by peptide diffusion in the extra-cellular space. We also have directly demonstrated significant heterogeneity between membrane domains enriched in different populations of receptors that help provide new explanations for the classical notions of receptor reserve and receptor desensitisation.
Ian Gibbins is Professor of Anatomy & Histology at Flinders University, having originally trained in zoology and pharmacology. For more than 30 years, he has worked on the microscopic structure and function of peripheral autonomic and visceral sensory neural pathways, focussing on the roles of neuropeptides in particular. Ian teaches extensively and has had major input into innovative curriculum design and delivery, especially in the Flinders Graduate Entry Medical Program. Ian is also a highly regarded published poet and electronic musician, with work broadcast on ABC Radio National, featured on international poetry sites, and in installations around Adelaide. His first full poetry collection and accompanying CD was published in 2012.