There are over a billion smokers worldwide, costing an estimated $5.6M annually in New Zealand (NZ) alone. High tobacco taxes in NZ, while effective in triggering smoking, have had serious financial impacts on those unable to stop smoking and their families. Smoking remains a big problem largely because smoking is very addictive. However, we now know that tobacco dependence is more complex than “just” the effect of nicotine. In fact tobacco smoke contains many hundreds of different compounds.

Within this project we aim to investigate which of these components could potentiate the addictive properties of nicotine, focussing predominantly on monoamine oxidase (MAO) inhibitors. As the term implies, MAO is involved in the breakdown of monoamines such as dopamine, noradrenaline and serotonin. In fact there are two different forms of MAO, with MAO-A more involved in the metabolism of noradrenaline and serotonin and MAO-B more involved in the metabolism of dopamine. Given that all drugs of abuse (including nicotine) increase dopamine neurotransmission, MAO inhibitors could contribute to the rewarding properties of such drugs by blocking the subsequent breakdown of dopamine.

Together with Drs Penny Truman and Rob Keijzers as well as AProf Paul Teresdale Spittle, we have identified several MAO inhibitors in the tobacco smoke and we are now investigating whether these components, alone or in combination with each other, enhance the rewarding properties of nicotine. To that extent we will use several behavioural paradigms such as conditioned place preference and self-administration.

This research is supported by grants from the Health Research Council and the NZ Ministry of Business, Innovation and Employment.