Referencia

Neuron, Volume 68, Issue 1, 6 October 2010, Pages 113-126

Autores

Marta Navarrete and Alfonso Araque

Resumen

El estudio desvela nuevos mecanismos de acción de los cannabinoides y endocannabinoides y de sus consecuencias funcionales en la transferencia de información en el sistema nervioso. En él se muestra que los endocannabinoides deprimen la transmisión sináptica cuando actúan directamente sobre receptores neuronales, pero potencian la eficacia de la conectividad sináptica cuando activan receptores en los astrocitos, un tipo de célula no neuronal que durante mucho tiempo se ha considerado que no participaba activamente en la transmisión de información que ocurre en el cerebro durante la actividad nerviosa. Estos hallazgos representan un cambio conceptual del conocimiento que hasta ahora se tenía sobre los mecanismos de acción de los cannabinoides y endocannabinoides, y consolidan la idea de que los astrocitos juegan un papel más relevante del que originalmente se pensaba en el funcionamiento del cerebro.

Descripción

Endocannabinoids and their receptor CB1 play key roles in brain function. Astrocytes express CB1Rs that are activated by endocannabinoids released by neurons. However, the consequences of the endocannabinoid-mediated neuron-astrocyte signaling on synaptic transmission are unknown. We show that endocannabinoids released by hippocampal pyramidal neurons increase the probability of transmitter release at CA3-CA1 synapses. This synaptic potentiation is due to CB1R-induced Ca+2 elevations in astrocytes, which stimulate the release of glutamate that activates presynaptic metabotropic glutamate receptors. While endocannabinoids induce synaptic depression in the stimulated neuron by direct activation of presynaptic CB1Rs, they indirectly lead to synaptic potentiation in relatively more distant neurons by activation of CB1Rs in astrocytes. Hence, astrocyte calcium signal evoked by endogenous stimuli (neuron-released endocannabinoids) modulates synaptic transmission. Therefore, astrocytes respond to endocannabinoid  that then potentiate synaptic transmission, indicating that astrocytes are actively involved in brain physiology.

Imágen artículo Noviembre

REFERENCIA DEL GRUPO E INVESTIGADOR
Nuestro grupo está interesado en determinar los aspectos celulares y moleculares que subyacen a la comunicación bidireccional entre astrocitos y neuronas y en esclarecer los procesos fisiológicos en los que participa dicha comunicación. En la actualidad perseguimos dos grandes líneas generales de investigación que pretenden aclarar el papel de los astrocitos en distintos aspectos de la fisiopatología del sistema nervioso.

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