Gortari P

Idioma: Español
Referencias bibliográficas: 36
Paginas: 185-190
Archivo PDF: 224.34 Kb.

RESUMEN

La motivación por el consumo de alimentos depende de la respuesta del núcleo paraventricular del hipotálamo, que integra señales centrales y periféricas, y que regula los sistemas neuroendocrinos. En respuesta a una deficiencia en la disponibilidad de alimentos, las neuronas que sintetizan péptidos orexigénicos del hipotálamo lateral y del núcleo arqueado se activan, mientras que se inhiben las que regulan negativamente la conducta alimentaria. El núcleo arqueado y el hipotálamo lateral se comunican con el núcleo paraventricular y modifican la actividad de sus células TRHérgicas; así, la restricción de alimentos reduce la liberación de la hormona liberadora de tirotropina (TRH), se acelera el eje tiroideo y la degradación de las reservas energéticas. A pesar del estricto control de la conducta alimentaria y de la variedad de señales que participan en él, estímulos estresantes pueden alterar la respuesta de los individuos ante un equilibrio negativo de energía, lo que ocasiona un trastorno alimentario. Con un modelo de anorexia por deshidratación, es posible inducir en ratas disminución del apetito y del peso, a partir del primer día del estudio. El funcionamiento del eje tiroideo de estos animales comparado con el de otro grupo con restricción alimentaria forzada, pero con motivación por comer, muestra una activación de las neuronas hipotalámicas de TRH, exclusiva de la anorexia. Además, analizamos ciertos factores que pueden participar en la falta de adaptación del eje tiroideo de los animales deshidratados con una baja disponibilidad de alimentos y ser los responsables de la conducta de anorexia.

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