Neurobiologia de las adicciones

Se había comentado en alguna entrada anterior que las drogas actúan como reforzadores. Un refuerzo es un consecuente que aumenta la probabilidad de ocurrencia de la respuesta a la que sigue. Aplicado al ámbito de la farmacología, se dice que una sustancia psicoactiva actúa como reforzador cuando probabiliza su autoadministración repetida. El consecuente, en este caso, es esa euforia casi inmediata que producen algunas drogas. * * Por ejemplo, mediante la técnica de autoestimulación eléctrica cerebral se ha comprobado que la estimulación directamente del accumbens es reforzante, incrementando la tasa de autoadministración de choques eléctricos sobre la zona. * * De la misma forma, la autoadministración de algunas drogas (estimulantes y depresores, principalmente, si bien cada una de ellas con características propias) parece estar asociado a una liberación de DopaminA.

Adicciones, 2008

The addictions are common chronic psychiatric diseases which represent a serious worldwide public-health problem. They have a high prevalence and negative effects at individual, family and societal level, with a high sanitary cost. Epidemiological genetic research has revealed that addictions are moderately to highly heritable. Also the investigation has evidenced that environmental and genetic factors contribute to individual differences in vulnerability to addictions. Advances in the neurobiology of addiction joined to the development of new molecular genetic technologies, have led to the identification of a variety of underlying genes and pathways in addiction process, leading to the description of common molecular mechanisms in substance and behaviour dependencies. Identifying geneenvironment interactions is a crucial issue in future research. Other major goal in genetic research is the identification of new therapeutic targets for treatment and prevention.

D efine la Organización Mundial de la Salud la adicción como una en fermedad crónica del cerebro que se caracte riza por la búsqueda y el uso compulsivo de sustancias adictivas, a pesar de las consecuencias nocivas. Las adicciones al tabaco y al alcohol son muy frecuentes, mientras que otras que tuvieron carácter epidémico (adicción a heroína) han per dido en gran parte el protagonismo, ce dido hoy a la cocaína, el cannabis y el éxtasis. De cocaína, cannabis, éxtasis y alcohol nos ocuparemos en este dossier. Están presentes de forma importante en nuestra sociedad, y seguirán estándolo. No hay duda que su consumo y su abuso conduce a patologías, accidentes, daño personal y coste económico a toda la sociedad. Bajo el consumo abusivo de todas ellas subyacen mecanismos de gratificación que tienen una clara base neurológica sustentada en complejos procesos moleculares. Los autores del presente dossier, expertos sobre las accio nes y la toxicidad de las drogas, trabajan en la frontera entre la psicología, la far macología y la bioquímica y biología molecular. El Dr. José Miñarro, de la Universidad de Valencia, se ocupa de la adicción a la cocaína, mientras que el profesor de la Universidad Complutense de Madrid e investigador del Instituto IBIMA, Dr. Fernando Rodríguez de Fonseca, se ocupa de los cannabinoides (los componentes activos de la marihua na y el hachís) y la Dra. Isabel Colado, también de la Universidad Complutense de Madrid, de las consecuencias del con sumo de éxtasis. Finalmente, yo misma revisaré las bases del alcoholismo. Ade más, en este mismo artículo trataré de dar unas pinceladas sobre rasgos comunes y preguntas básicas que pueden hacerse para todas o muchas de las adicciones.

Revista Internacional de Investigación en Adicciones, 2016

Introduction: addiction is considered a central nervous system disease that consists of three stages: intoxication, withdrawal and craving. The neurobiological model of addictions proposed by Volkow et al. (2003) includes the states of control, memory, motivation and reward, however, in order to generate an explicit and universal solution to this disease is necessary to mathematize theoretical models. Objective: to propose and to develop the mathematization of a stochastic model using Markov Chains in the phenomenon of psychoactive substances and addiction. Method: mathematization of a stochastic model using Markov Chains and differential equations. Results: using Markov Chains, models of two brains were compared, one healthy (no consumer of psychoactive substances) against one of a person with addiction and through transition probabilities we observed differences from one model to another. Differential equations were used to estimate the time of the effect of a drug in the body and combined with trigonometric equations we sought to estimate the best function to continue with an addiction and relapse. Discussion and conclusions: the obtained mathematical modeling indicates that the neurobiological model of addictions may be represented by a Markov Chain inhomogeneous. In the case of a healthy brain, it can pass with equal probability (p = 1/3) from one state to another, in the case of a person with addiction, the transition probabilities depend on time, drug type, dose and route of administration.

The addictions are common chronic psychiatric diseases which represent a serious worldwide public-health problem. They have a high prevalence and negative effects at individual, family and societal level, with a high sanitary cost. Epidemiological genetic research has revealed that addictions are moderately to highly heritable. Also the investigation has evidenced that environmental and genetic factors contribute to individual differences in vulnerability to addictions. Advances in the neurobiology of addiction joined to the development of new molecular genetic technologies, have led to the identification of a variety of underlying genes and pathways in addiction process, leading to the description of common molecular mechanisms in substance and behaviour dependencies. Identifying geneenvironment interactions is a crucial issue in future research. Other major goal in genetic research is the identification of new therapeutic targets for treatment and prevention.

2005

Opiate drugs are highly addictive substances. Opiates produce acute and long-term adaptive changes at celular and molecular level in the central nervous system that are responsible for the addictive disorder. Reinforcing effects of opiates (euphoria, well being) are involved in the initiation of the opiate use, while negative effects (dysphoria during the abstinence) are responsible for the maintenance of the addictive behaviour. Biochemical, pharmacological, electrophysiological and molecular studies have identified several neurochemical pathways within the mesolimbic system as a common neurobiological substrate for the reinforcing effects of all the drugs of abuse, including opiates. The mesolimic dopaminergic system and the neural pathways involved in the physiological responses to stress mediate the motivational negative effects associated to opiate withdrawal. Finally, opiates produce long-term adaptive changes at the level of several transcription factors that could participate in the increased vulnerability to relapse in the addictive behaviour observed even after long periods of drug abstinence..

como evolucionan las adicciones

2010

International data found that the severity of the problem epidemiological, clinical comprehensive assessments recommend to patients abusers/addicts and use of psychotropic diagnostic tools, whose efficiency makes them useful elements in certain brain pathologies. We describe the neuroanatomy-physiology of the areas involved in the production of addictive disease as a centre of management and long-term rehabilitation. It indicates the role of frontal cortical structures in human behaviour which disables alteration to the individual to assess the potential reward associated with self-medication. Emphasis is placed in the imagenological participation in the diagnosis and management of these disorders, techniques that make it over him without invading and where the identification of underlying neuro-biochemical mechanisms is crucial. It highlights the resources for better long term psychotherapeutic rehabilitation that joins the utility-educational information to patients and their fami...