Efecto de la activación adrenérgica insular en la neofobia gustatoria
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2016
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es
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Universidad Andrés Bello
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Licencia CC
Licencia CC
Resumen
La respuesta frente al estrés corresponde a la capacidad de un organismo de
responder frente a un estímulo estresante y volver a su homeostasis. Esta respuesta es
iniciada por la respuesta autonómica, mediada principalmente por actividad adrenérgica,
la cual es modulada por catecolaminas, entre las cuales se destacan la norepinefrina
(NE) a nivel de sistema nervioso central, y epinefrina (EPI) a nivel periférico.
Se conoce una serie de áreas del cerebro asociadas a la respuesta al estrés,
incluyendo la amígdala extendida, locus coeruleus, hipocampo, corteza prefrontal, entre
varias. Una de las áreas del cerebro que ha sido propuesta muy recientemente como
mediadora de la respuesta fisiológica frente al estrés es la corteza insular. Esta área
recibe información emocional, visceral y gustatoria, y aún se desconoce por qué su
actividad se ve alterada en trastornos de ansiedad. Es posible estudiar el rol de la ínsula
en ansiedad usando conductas asociadas a gustos que sean sensibles al estrés y
ansiedad, como la neofobia gustatoria. La neofobia gustatoria se describe como el
miedo a un gusto nuevo, y es exacerbada en ambientes de estrés (hiponeofagia),
siendo una medición de comportamiento tipo ansioso en animales.
Este trabajo tuvo como objetivo evaluar si la actividad adrenérgica en la corteza
insular media el aumento en neofobia gustatoria inducido por la presentación de un
gusto nuevo en un ambiente de alta exaltación. La hipótesis que sustenta este trabajo
es que la actividad adrenérgica en la corteza insular aumenta la neofobia
gustatoria y modula el incremento de neofobia inducida por un ambiente de alta
exaltación. Para probar la hipótesis se usó una combinación de microinyecciones de
NE y propranolol intra insular y de inyecciones subcutáneas de EPI y propranolol, antes
de la presentación del gusto en contextos con alta y baja exaltación. Los resultados
obtenidos apoyan la hipótesis. Nuestros resultados proponen que la actividad
adrenérgica periférica media la respuesta de neofobia gustatoria en ambientes de alta
exaltación, efecto que es modulado por actividad adrenérgica en la corteza insular.
The stress response is the ability of an organism to respond to a stressor and return to homeostasis. The first body's response to stress is the autonomic response, primarily mediated by adrenergic activity, which is modulated by catecholamines, among which norepinephrine is the predominant in the central nervous system, and epinephrine peripherally. Studies show that a dysregulation in the levels of these hormones may lead to psychiatric disorders including anxiety disorders. Among several brain areas involved in stress response, including the extended amygdala, locus coeruleus, hippocampus and prefrontal cortex, the insular cortex has been recently associated with physiological responses to stress. This area receives emotional, visceral and gustatory information, but it is still unknown why its activity is altered in anxiety disorders. It is possible to study the role of the insula in anxiety using behaviors associated with tastes which are sensitive to stress and anxiety, such as gustatory neophobia. The gustatory neophobia is the reluctance or fear to try a new taste, and is exacerbated in arousing contexts (also known as hyponeophagia), being a widely used to measure anxiety in animals. This study aimed to evaluate to which extent the adrenergic activity in the medial insular cortex increases gustatory neofobia induced by arousing novel contexts. The hypothesis behind this study is that adrenergic activity in the insular cortex increases taste neophobia and modulates the increment in neophobia induced by an arousing context. To test this hypothesis we used a combination of intrainsular microinjections of norepinephrine and propranolol and peripheral injections of epinephrine and propranolol before presentation of a novel taste in contexts of high and low arousal. Our results support the hypothesis and suggest that peripheral adrenergic activity mediates arousal induced increases in neophobia, effect that is mediated by adrenergifc activity in the insular cortex.
The stress response is the ability of an organism to respond to a stressor and return to homeostasis. The first body's response to stress is the autonomic response, primarily mediated by adrenergic activity, which is modulated by catecholamines, among which norepinephrine is the predominant in the central nervous system, and epinephrine peripherally. Studies show that a dysregulation in the levels of these hormones may lead to psychiatric disorders including anxiety disorders. Among several brain areas involved in stress response, including the extended amygdala, locus coeruleus, hippocampus and prefrontal cortex, the insular cortex has been recently associated with physiological responses to stress. This area receives emotional, visceral and gustatory information, but it is still unknown why its activity is altered in anxiety disorders. It is possible to study the role of the insula in anxiety using behaviors associated with tastes which are sensitive to stress and anxiety, such as gustatory neophobia. The gustatory neophobia is the reluctance or fear to try a new taste, and is exacerbated in arousing contexts (also known as hyponeophagia), being a widely used to measure anxiety in animals. This study aimed to evaluate to which extent the adrenergic activity in the medial insular cortex increases gustatory neofobia induced by arousing novel contexts. The hypothesis behind this study is that adrenergic activity in the insular cortex increases taste neophobia and modulates the increment in neophobia induced by an arousing context. To test this hypothesis we used a combination of intrainsular microinjections of norepinephrine and propranolol and peripheral injections of epinephrine and propranolol before presentation of a novel taste in contexts of high and low arousal. Our results support the hypothesis and suggest that peripheral adrenergic activity mediates arousal induced increases in neophobia, effect that is mediated by adrenergifc activity in the insular cortex.
Notas
Tesis (Magíster en Biotecnología)
Este proyecto ha sido financiado por el Proyecto Fondecyt nº 1130724.
Este proyecto ha sido financiado por el Proyecto Fondecyt nº 1130724.
Palabras clave
Fobias, Análisis, Estrés (Fisiología), Corteza Cerebral