Compresiones neurovasculares de la fosa craneal posterior en la neuralgia del trigémino. Estudio anatomoclínico

La neuralgia del trigémino (NT) es un síndrome doloroso facial caracterizado por un dolor neuropático paroxístico irradiado al territorio sensitivo del nervio trigémino. A lo largo de las últimas décadas la creciente evidencia experimental y clínica ha contribuido a establecer la teoría de una compresión neurovascular (CNV) del nervio trigémino como causa fundamental de este trastorno. Esta teoría apoya el tratamiento quirúrgico de la NT mediante una descompresión microvascular (DMV). Actualmente la DMV es aceptada como la primera opción de tratamiento quirúrgico de la NT refractaria a tratamiento médico. Pese a la cantidad de trabajos que analizan la utilidad de la RM preoperatoria con secuencias de alta resolución volumétricas potenciadas en T2 (RM 3DT2), no hay unanimidad respecto a la precisión de estas secuencias de RM para el diagnóstico y la caracterización de una posible CNV en pacientes con NT refractaria candidatos a tratamiento mediante DMV...

Infralimbic cortex controls the activity of the hypothalamus-pituitary adrenal axis and the formation of aversive memory: effects of environmental enrichment

The aim of the present study was to investigate the effects of the stimulation and inhibition of the ventral part of the medial prefrontal cortex (infralimbic cortex) on basal and stress-induced plasma levels of corticosterone and on the acquisition of aversive memory in animals maintained in control and environmental enrichment (EE) conditions. Intracortical microinjections of the GABAA antagonist picrotoxin and agonist muscimol were performed in male Wistar rats to stimulate and inhibit, respectively, the activity of the infralimbic cortex. Injections were performed 60 min before foot shock stress and training in the inhibitory avoidance task. Picrotoxin injections into the infralimbic cortex increased basal plasma levels of corticosterone. These increases were higher in EE rats which suggest that EE enhances the control exerted by infralimbic cortex over the hypothalamus-pituitary-adrenal (HPA) axis and corticosterone release. Muscimol injections into the infralimbic cortex reduced the stress-induced plasma levels of corticosterone and the retention latency 24 h after training in the inhibitory avoidance performance in control and EE animals, respectively. These results further suggest that the infralimbic cortex is required for the activation of the HPA axis during stress and for the acquisition of contextual aversive memories.