Caroline Brennan

We are interested in the molecular mechanisms controlling behaviour. We are particularly interested in endophenotypes associated with psychological disease including drug addiction and dementia. We use zebrafish as our model system combining behavioural analysis, imaging and cell biology techniques in wild type, mutant and transgenic lines to investigate the neural correlates of reward and learning behaviours.

Behavioural Phenotypes.
1) Drug dependence.
We have developed zebrafish assays of reward seeking, compulsive behaviour and relapse (Kily et al, 2008, Brennan et al, 2010, Brennan 2011) as well as an assay of impulsivity (Parker et al 2011) which in mammals predicts tendency to relapse. We use these assays in forward and reverse genetic screens to identify molecular mechanisms underlying the behaviours and to explore the effects of developmental exposure to drugs of abuse. In collaboration with the Schools of Electronical Engineering and Computing and Engineering and Material Science we are in the process of automating our assays.

2) Learning and Attention.
We have automated two choice discrimination assays that we use to assess learning and attention in the various zebrafish lines. In addition, our n choice serial reaction time assay (Parker et al 2011) can be used to assess attention in zebrafish. These assays are used to screen mutant lines and, in collaboration with Dr J Viles, QMUL the pathology of beta-amyloid induced dementia.

Imaging.
Imaging analysis is performed in collaboration with Dr Rachel Ashworth, QMUL. Rachel has over 10 years experience in the analysis of Ca2+ transients in zebrafish. We use analysis of GFP transgenic lines and gCaMP reporter lines to relate neural activity and network formation to behaviour.



Matt Parker

Zebrafish are fast becoming a popular model species for studying human medical conditions and in our lab, we are developing zebrafish models of drug addiction. The DSM—IV lists compulsive drug seeking as one of the three main diagnostic criteria for drug dependence in humans, and as such, any model species should have individuals which demonstrate this. Using conditioned place preference (CPP), our lab recently demonstrated that zebrafish not only show a strong CPP response to both alcohol and nicotine, but also show signs of compulsivity, in that their choice of the drug-paired environment in the CPP persisted despite counter-conditioning with aversive cues (Kily et al. 2008). My research, funded by the NC3Rs, has three specific aims:

1. Developing behavioural assays of stress-responsivity, novelty seeking, impulsivity and compulsive drug-seeking in zebrafish (Danio Rerio).
2. Behavioural phenotyping of existing wild-type lines to establish endophenotypes (causal factors) for compulsive drug seeking and relapse.
3. Generate high- and low-responder lines carrying ENU-induced mutations that can be used for mapping to identify linked alleles. This work is of fundamental importance in terms of developing new and specifically targeted therapeutics to help to combat drug addiction. In addition, our aims are to develop screens for larval phenotypes, which will ultimately reduce the need for using adult animals in drug testing.



Mollie Millington

Currently, I support Matt and Alistair by assissting with behavioural assays (tank diving, conditioned place preference, etc) and breeding. Some of my time is spent helping out the aquarium with cleaning, feeding, and fry rearing. My personal project is a collaboration with UnoBV, in which I am examining the plausibility of pit-tagging zebrafish for individual identification. I am also investigating optimal housing conditions for zebrafish that balance acceptable welfare and data reliability. My time in the molecular lab is spent running cortisol assays, managing the lab and working with project students.





Fraser Combe

As well as managing the day-to-day running of the aquarium facilities I also support research within the group. My focus is on identifying dopaminergic receptors using transgenic cloning and the insertion of a fluorescent calcium sensitive protein. Secondly our aim is to try and improve fish welfare and the 3R’s. As currently little is known, we are conducting research on how differential housing conditions can affect the physiological and behavioural stress responses of zebrafish. Refinement of fry rearing protocols will improve our husbandry methods providing a more defined protocol which will enable the reduction in use of fish through improved survival as well as reducing the effects of variable rearing on the future behaviour of zebrafish.



Matteo Baiamonte

Addiction is a dysfunction of the motivational system that results in a series of complex behavioural symptoms, critically compulsive drug taking and tendency to relapse (return to drug taking despite prolonged abstinence). Stress has long been related to increased vulnerability to addiction. The last few years of research have extended our understanding of the underlying mechanisms for this association, including evidence of molecular and cellular changes associated with chronic stress and addiction.

Physiological responses to stress are mainly manifested through the hypothalamic-pituitary-adrenocortical (HPA) axis and we are interested in the role that HPA axis has in different aspects of addiction. Products of the HPA axis activation are involved in the modulation of the mesolimbic system, a pathway highly implicated in drug addiction. Interactions between these two pathways occur at different levels, for example, glucocorticoid enhances dopamine release in the mesolimbic pathway, and the suppression of the same hormone by adrenalectomy results in a reduced dopamine release.

Developmental exposure to stress has also been implicated in drug self-administration and relapse. Prolonged and repeated maternal separation (MS) in neonatal rats significantly alters central CRH pathways development, and produced decreased dopamine transporter expression with increased dopamine and behavioural responses to stress (Meaney., 2002). The effects of developmental exposure in the HPA axis is an area in science that is still growing. If it causes changes to an extent it results in a maladapted stress responding pathway, it could yield an increased vulnerability to drug dependence and susceptibility to relapse upon stressful conditions. My project focuses in the developmental aspect of drug exposure and its subsequent effects in the stress management system, such as, the HPA axis.



Alistair Brock

My research involves identifying fundamental mechanisms underlying addictive behaviour that cross the barriers between species. Using a Zebrafish model of nicotine addiction we hope to screen candidate genes for their effect on the dopamine pathway and other reward mechanisms implicated in drug dependence. Also by breeding and analyzing mutagenised lines of Zebrafish obtained from the Sanger Institute we will look to identify new genetic markers for addiction and display the levels of heritability involved. The potential also exists to identify individuals who might respond to specific therapies for dependence. The ultimate aim of these studies is to develop safer, more effective treatments for addictive disorders.

The work will also involve the organisation of a clinical trial with the aim of investigating how smokers with varying genetic makeup respond to different types of nicotine replacement therapy. It is hoped data collected from these human studies will allow the delivery of treatments more tailored to an individual’s needs, therefore increasing the likelihood of the individual kicking the habit. Any loci identified in the fish study will be able to inform studies of this type.