TY - JOUR T1 - Stress-induced modulation of endocannabinoid signaling leads to delayed strengthening of synaptic connectivity in the amygdala. JF - Proc Natl Acad Sci U S A Y1 - 2020 A1 - Yasmin, Farhana A1 - Colangeli, Roberto A1 - Morena, Maria A1 - Filipski, Sarah A1 - van der Stelt, Mario A1 - Pittman, Quentin J A1 - Hillard, Cecilia J A1 - Teskey, G Campbell A1 - McEwen, Bruce S A1 - Hill, Matthew N A1 - Chattarji, Sumantra KW - Administration, Oral KW - Amidohydrolases KW - Animals KW - Basolateral Nuclear Complex KW - Cannabinoid Receptor Antagonists KW - Disease Models, Animal KW - Emotions KW - Endocannabinoids KW - Enzyme Inhibitors KW - Excitatory Postsynaptic Potentials KW - Humans KW - Male KW - Rats KW - Receptor, Cannabinoid, CB1 KW - Signal Transduction KW - Stress, Psychological AB -

Even a brief exposure to severe stress strengthens synaptic connectivity days later in the amygdala, a brain area implicated in the affective symptoms of stress-related psychiatric disorders. However, little is known about the synaptic signaling mechanisms during stress that eventually culminate in its delayed impact on the amygdala. Hence, we investigated early stress-induced changes in amygdalar synaptic signaling in order to prevent its delayed effects. Whole-cell recordings in basolateral amygdala (BLA) slices from rats revealed higher frequency of miniature excitatory postsynaptic currents (mEPSCs) immediately after 2-h immobilization stress. This was replicated by inhibition of cannabinoid receptors (CBR), suggesting a role for endocannabinoid (eCB) signaling. Stress also reduced -arachidonoylethanolamine (AEA), an endogenous ligand of CBR. Since stress-induced activation of fatty acid amide hydrolase (FAAH) reduces AEA, we confirmed that oral administration of an FAAH inhibitor during stress prevents the increase in synaptic excitation in the BLA soon after stress. Although stress also caused an immediate reduction in synaptic inhibition, this was not prevented by FAAH inhibition. Strikingly, FAAH inhibition during the traumatic stressor was also effective 10 d later on the delayed manifestation of synaptic strengthening in BLA neurons, preventing both enhanced mEPSC frequency and increased dendritic spine-density. Thus, oral administration of an FAAH inhibitor during a brief stress prevents the early synaptic changes that eventually build up to hyperexcitability in the amygdala. This framework is of therapeutic relevance because of growing interest in targeting eCB signaling to prevent the gradual development of emotional symptoms and underlying amygdalar dysfunction triggered by traumatic stress.

VL - 117 IS - 1 ER -