Javier Navarro-Zaragoza

By Javier Navarro-Zaragoza, María Victoria Milanés and María Luisa Laorden

Stressful situations can result in relapse in dependent or abstinent causing reinstatement of drug-seeking. In fact, it has been suggested that activation of the brain stress system results in glucocorticoid release that affects the dopaminergic pathways. Also, the noradrenergic system innervates the extrahypothalamic BSS from the nucleus of tractus solitarius (NTS), resulting in a feedforward loop between the corticotropin-releasing factor (CRF) and noradrenaline (NA) crucial in drug addiction and relapses. Glucocorticoids interact with two receptors: mineralocorticoid receptor (MR) and glucocorticoid receptor (GR) which bind to a GRE site located in tyrosine hydroxylase (TH), resulting in the upregulation of TH synthesis and, finally, increasing dopamine (DA) release in the nucleus accumbens. TH upregulation depends on the phosphorylation of serine 31 and/or serine 40. Previous research has shown that protein kinase C (PKC) activates extracellular signal-regulated kinase (ERK) pathway and in turn phosphorylates serine 31 in the NTS. Besides, cAMP response element binding protein (CREB) is regulated by PKA and PKC. The results shown after pretreating morphine-withdrawn rats with mifepristone and spironolactone (GR and MR antagonists, respectively) suggest that glucocorticoids have a prominent role in addiction because GR would activate ERK and CREB in the NTS, phosphorylating serine 31 and activating TH and indeed noradrenergic release in the paraventricular nucleus (PVN).

Part of the book: Opioids

By María-Lucía Fernández-López, Javier Navarro-Zaragoza and María Falcón Romero

The misuse of mobile phones has been recognized as a significant issue, potentially leading to health problems and even addiction. Smartphone addiction is defined as the inability to stop using the device despite physical, psychological, or social consequences. Adolescents, in particular, are considered highly susceptible to this phenomenon. In fact, the diagnosis of this disorder is increasing exponentially among adolescents, even more so after the coronavirus disease 2019 (COVID-19) pandemic, since it has exacerbated the reliance on technology for social, educational, and professional purposes. Excessive mobile phone use among adolescents has been associated with limited academic performance, low self-esteem, and poor social relationships, as well as impulsivity, anxiety, and stress. Additionally, intensive mobile phone use has been linked to substance abuse, including alcohol and other drugs. Thus, this chapter aims to revise smartphone addiction, drug consumption, and self-perceived well-being during adolescence; the influence of the COVID-19 pandemic on these factors; and the available tools for their measurement.

Part of the book: Multidisciplinary Approach for Better Understanding of Addictive Behaviour

By Elena Martínez Laorden, Fátima Martín-Sánchez, María-Lucía Fernández-López, Alberto Cánovas, Francisco Javier Teruel-Fernández, Javier Navarro-Zaragoza and Pilar Almela Rojo

The conditioned-place aversion (CPA) paradigm is a widely used animal model for determining the dysphoric and aversive properties of withdrawal, as well as to study the neural substrates underlying the aversive memory associated with drug withdrawal. Therefore, one of the aims of the present chapter was to investigate possible strain differences in morphine-withdrawn mice after CPA training. Different studies have shown that corticotrophin-releasing factor (CRF) is critically involved in aversion-driven associative learning. So, we also measured the effects of CP-154,526, a selective CRF1 receptor (CRF1R) antagonist, on CPA activation and extinction and on brain-derived neurotrophic factor (BDNF) expression in dentate gyrus (DG) and basolateral amygdala (BLA), two limbic areas that play a critical role in emotional learning and memory. In the last section of the chapter, we show our main results concerning the effects of encapsulating morphine in liposomes on CPA expression and extinction. Our results indicate a crucial role for CRF, through CRF1R, in molecular changes involved in aversive memory expression and extinction demonstrating that CRF1R antagonists might be a potential therapeutic target in drug addiction. Finally, morphine encapsulation in liposomes could mitigate the progress of addiction and constitute a good option for the therapeutic use of this drug.

Part of the book: Multidisciplinary Approach for Better Understanding of Addictive Behaviour

By Lucía Fernández-López, Elena Martínez Laorden, Fatima Martín Sánchez, Pilar Almela Rojo and Javier Navarro-Zaragoza

Social media are digital platforms that allow users to create, share, and view media content, as well as interact with each other through the internet. They facilitate communication, socialization, and the dissemination of information on a global scale. Its use presents many advantages. In addition to the fact that they provide entertainment, social media also facilitate instant communication and help with the dissemination of information in real time. Furthermore, from a business perspective, the visibility of brands is enhanced. Finally, they can also be used for educational and pedagogical purposes. Despite all these benefits, the use of social media also has a negative side. From a health perspective, social media can have negative effects on physical and mental health and can even lead to addiction. Social media addiction has been also found to be associated with numerous issues, including emotional, relational, health, and performance-related problems. Thus, this chapter aims to review the effect of social media use on the health of users.

Part of the book: Substance Abuse