Prof. Trevor Lamb

Rod photoreceptor recorded using suction pipette and patch pipette (TD Lamb & HR Matthews).

Biography

After obtaining a degree in electronic engineering at Melbourne University, Trevor Lamb transferred to physiology, before travelling to Cambridge in 1971 to undertake his Ph.D. There he met Denis Baylor in Alan Hodgkin's laboratory, and under their guidance began working on the retina: first on horizontal cells and then on photoreceptors.

During a productive post-doc in Baylor's lab in Stanford in 1977, he, King-Wai Yau, and Baylor developed the suction pipette technique for recording electrically from photoreceptors, and discovered that rods could respond reliably to individual photons of light. Subsequently he was based in Cambridge for 25 years, and continued to work on photoreceptors - on the molecular mechanisms of activation and inactivation of the light response, and on light adaptation and dark adaptation.

In the early 1990s he and Edward Pugh (at University of Pennsylvania) developed a mathematical description of the molecular reactions underlying the onset phase of the photoreceptor's light response, which has provided important insights into the transduction mechanism. In the mid-1990s he branched out into using the electroretinogram (ERG) as a tool for studying photoreceptors in vivo. Most recently he has investigated the evolutionary origin of the retina and photoreceptors.

In 1993 Trevor was elected a Fellow of the Royal Society, and in the following year he was promoted to a chair at Cambridge. In 2003 he returned to Australia as a Federation Fellow at the John Curtin School of Medical Research, ANU. Currently he is Distinguished Professor at ANU and is Research Director of the ARC Centre of Excellence in Vision Science (www.vision.edu.au).

Research Interests

Response recovery and adaptation in vertebrate photoreceptor

Fivos Vogalis at the suction pipette electrophysiology rig.

We make suction pipette recordings from single photoreceptors isolated from the retinas of transgenic zebrafish, and from wild-type mice. We study the factors that contribute to the speed of recovery of the cells from light exposure. This research is being undertaken by Dr Fivos Vogalis, and we collaborate with Professor Yoshitaka Fukada at Tokyo University.

Molecular, cellular, and functional differences between rod and cone photoreceptors

In a collaboration with Professor Ed Pugh at the University of Pennsylvania, we are attempting to explain how the enormous functional differences between rods and cones can be explained by the fairly subtle differences at the molecular and cellular level. How is it that rods are able to respond reliably to individual photon hits, but saturate at low ambient intensities, whereas cones are somewhat less sensitive, yet are able to continue responding no matter how intense the steady illumination is made?

Recovery of human photoreceptors and retinal bipolar cells from intense bleaching exposures

Allison Cameron at the ganzfeld electroretinogram rig.

We record the electroretinogram from the human eye in response to flashes of light delivered at various times after exposure of the eye to very intense illumination that 'bleaches' a proportion of the visual pigment. The stimuli can be designed to elicit responses from cones, from rods, or from rod bipolar cells. We have shown that the characteristic dark adaptation behaviour of the overall human visual is present even at the first synapse: at the level of retinal rod bipolar cells. This research has been undertaken by Dr Allison Cameron.

Evolution of vertebrate photoreceptors and the vertebrate retina

Recently, we have begun a collaboration with Professor Shaun Collin at University of Queensland and with Ed Pugh, to attempt to account for the myriad of tiny steps that led to the evolution of the vertebrate eye. We have obtained preliminary evidence to indicate that the remarkable "eye" of the hagfish may provide clues to a step in the evolution of our own eyes. We are embarking on a project studying the morphology and electrophysiology of the hagfish retina and photoreceptors, and the phylogenetic position of the hagfish.

Recent Publications (since 2003)

• Cameron AM, Miao L, Ruseckaite R, Pianta MJ, & Lamb TD (2008). Dark adaptation recovery of human rod bipolar cell response kinetics estimated from scotopic b-wave measurements. Journal of Physiology. [In press, accepted 16 September 2008]. http://jp.physoc.org/cgi/content/abstract/jphysiol.2008.160028v1
• Lamb TD, Pugh EN Jr & Collin SP (2008). The origin of the vertebrate eye. Evolution: Education & Outreach 8(4) [In press, accepted 10 September 2008]. http://dx.doi.org/10.1007/s12052-008-0091-2
• Lamb TD, Collin SP & Pugh EN Jr (2007). Evolution of the vertebrate eye: Opsins, photoreceptors, retina, and eye-cup. Nature Reviews Neuroscience 8, 960-975. http://www.nature.com/nrn/journal/v8/n12/abs/nrn2283.html
• Lamb TD & Pugh EN Jr (2006). Phototransduction, dark adaptation, and rhodopsin regeneration. The Proctor Lecture. Investigative Ophthalmology and Visual Science 47, 5138-5152. http://www.iovs.org/cgi/reprint/47/12/5138
• Cameron AM, Mahroo OAR & Lamb TD (2006). Dark adaptation of human rod bipolar cells measured from the b wave of the scotopic electroretinogram. Journal of Physiology 575, 507-526. http://jp.physoc.org/cgi/content/abstract/575/2/507
• van Hateren JH & Lamb TD (2006). The photocurrent response of human cones is fast and monophasic. BMC Neuroscience 7, 34. http://www.biomedcentral.com/1471-2202/7/34/abstract
• Wenzel A, Oberhauser V, Pugh EN Jr, Lamb TD, Grimm C, Samardzija M, Seeliger MW, Remé CE & von Lintig J (2005). The retinal G protein-coupled receptor (RGR) enhances isomerohydrolase activity independent of light. Journal of Biological Chemistry 280, 29874-29884.
• http://www.jbc.org/cgi/content/abstract/280/33/29874 Kenkre JS, Moran NA, Lamb TD & Mahroo OAR (2005). Extremely rapid recovery of human cone circulating current at the extinction of bleaching exposures. Journal of Physiology 567, 95-112. http://jp.physoc.org/cgi/content/abstract/567/1/95
• Jarvinen JLP & Lamb TD (2005). Inverted photocurrent responses from amphibian rod photoreceptors: role of membrane voltage in response recovery. Journal of Physiology 566, 455-466. http://jp.physoc.org/cgi/content/abstract/566/2/455
• Hamer RD, Nicholas SC, Tranchina D, Lamb TD & Jarvinen JLP (2005). Towards a unified model of vertebrate rod phototransduction. Visual Neuroscience 22, 417-432. http://dx.doi.org/10.1017/S0952523805224045
• Lamb TD & Pugh EN Jr (2004). Dark adaptation and the retinoid cycle of vision. Progress in Retinal and Eye Research 23, 307-380. http://dx.doi.org/10.1016/j.preteyeres.2004.03.001
• Friedburg C, Allen CP, Mason PJ & Lamb TD (2004). Contribution of cone photoreceptors and post-receptoral mechanisms to the human photopic electroretinogram. Journal of Physiology 556, 819-834. http://jp.physoc.org/cgi/content/abstract/556/3/819
• Mahroo OAR & Lamb TD (2004). Recovery of the human photopic electroretinogram after bleaching exposures: estimation of pigment regeneration kinetics. Journal of Physiology 554, 417-437. http://jp.physoc.org/cgi/content/abstract/554/2/417
• Hamer RD, Nicholas SC, Tranchina D, Liebman PA & Lamb TD (2003). Multiple steps of phosphorylation of activated rhodopsin can account for the reproducibility of vertebrate rod single-photon responses. Journal of General Physiology 122, 419-444. http://www.jgp.org/cgi/content/abstract/122/4/419
• Burns ME & Lamb TD (2003). Visual transduction by rod and cone photoreceptors. In The Visual Neurosciences (ed. Chalupa, L.M. & Werner, J.S.), Chapter 16, pp. 215-233. MIT Press, Cambridge MA. ISBN 0-262-03308-9.