Inhibition of mitochondrial permeability transition pore opening contributes to cannabinoid type 1 receptor agonist ACEA-induced neuroprotection

Cannabinoid type 1 (CB1) receptor agonist arachidonyl-2-chloroethylamide (ACEA) induces neuroprotection against brain ischemia, and the mechanism, however, is still elusive. In this study, we used bilateral common carotid artery occlusion (BCCAO) in mice and oxygen-glucose deprivation (OGD) in primary cultured neurons to mimic brain ischemic injury, and hypothesized that cannabinoid CB1 receptor agonist ACEA protects ischemic neurons via inhibiting the opening of mitochondrial permeability transition pore (MPTP). In vivo, we found that BCCAO treatment reduced the neurological functions, increased the number of apoptotic neuronal cells and deteriorated the mitochondrial morphology in the ischemic brain tissue. And in vitro, we observed that OGD injury reduced cell viability, mitochondrial function and anti-oxidant SOD2 expression, increased lactate dehydrogenase (LDH), mitochondrial cytochrome C (Cyto C) and apoptosis-inducing factor (AIF) releases, elevated the cell apoptosis and mitochondrial superoxide level. And the CB1 receptor agonist ACEA significantly abolished the BCCAO and OGD-induced neuronal injury above. However, the MPTP opener atractyloside (Atr) markedly reversed the ACEA-induced neuroprotective effects, inhibited the mitochondrial Cyto C and AIF releases and relieved the mitochondrial swelling, but the MPTP inhibitor cyclosporin A (CsA) did not cause significant effects on the ACEA-induced neuroprotection above. These findings indicated that inhibition of MPTP opening may be involved in the cannabinoid CB1 receptor agonist ACEA-induced neuroprotection.