A team of researchers at UPF has identified an endogenous peptide that is involved in relapses into smoking after a period of abstinence.

The results are shown in a study published on 10 February in the Journal of Neuroscience by researchers in the Neuropharmacology Laboratory headed by professor Rafael Maldonado, of the UPF Department of Experimental and Health Sciences (CEXS), with Stanford University (USA).

The study is part of the doctoral thesis being written by the researcher Ainhoa Plaza-Zabala, the lead author of the article, under the supervision of Fernando Berrendero, co-author of the paper.

The experiment shows that hypocretins play a significant role in relapses into smoking. This basic research work was carried out on an animal model in mice, with self-administered nicotine.

Substances related to anxiety and addiction

The hypocretins (also known as the orexins) are peptide neuromodulators found in the neurons of the cerebral hypothalamus. These substances are linked to the metabolism of energy, the regulation of food intake and wakefulness. They have recently been associated with reward mechanisms and with addiction . An increase in hypocretin activity has been found to create states of anxiety that can lead to a relapse into the consumption of substances that can cause addiction.

The main conclusions of this important study carried out by researchers at UPF are that hypocretins play a key role in the modulation of episodes of anxiety arising from the effects of nicotine, and in the underlying neurobiological processes in relapses into smoking.

Furthermore, hypocretins modulate the effects of nicotine on anxiety by interacting with corticotropin-releasing factors (CRF), a peptide involved in the response to stress, and with the vasopressin (AVP) neurons in the hypothalamus.

Finally, CRF and hypocretins act independently but are complementary in the physiological process during a relapse into nicotine consumption. This has important implications when designing a therapeutic strategy based on blocking the action of these two peptides to prevent a relapse into tobacco consumption after a period of abstinence.

Tobacco smoking is one of the consumption habits with the highest levels of addiction, as well as being a significant healthcare problem. This addiction entails a loss of control over consumption, and a syndrome of abstinence after giving up smoking which encourages relapses, even after long periods of abstinence. The main objective of treatments for dependence on smoking is to prevent a relapse.

For further reference, see:

Ainhoa Plaza-Zabala, Elena Martín-García, Luis de Lecea, Rafael Maldonado and Fernando Berrendero, " Hypocretins Regulate the Anxiogenic-Like Effects of Nicotine and Induce Reinstatement of Nicotine-Seeking Behavior", The Journal of Neuroscience, 10 February 2010.