The effect of palmitoylethanolamide (PEA), an endogenous fatty acid amide displaying neuroprotective actions, on glutamate release from rat cerebrocortical nerve terminals (synaptosomes) was investigated. PEA inhibited the Ca²⁺-dependent release of glutamate, which was triggered by exposing synaptosomes to the potassium channel blocker 4-aminopyridine. This release inhibition was concentration dependent, associated with a reduction in cytosolic Ca²⁺ concentration, and not due to a change in synaptosomal membrane potential. The glutamate release-inhibiting effect of PEA was prevented by the Ca(v)2.1 (P/Q-type) channel blocker ω-agatoxin IVA or the protein kinase A inhibitor H89, not affected by the intracellular Ca²⁺ release inhibitors dantrolene and CGP37157, and partially antagonized by the cannabinoid CB1 receptor antagonist AM281. Based on these results, we suggest that PEA exerts its presynaptic inhibition, likely through a reduction in the Ca²⁺ influx mediated by Ca(v)2.1 (P/Q-type) channels, thereby inhibiting the release of glutamate from rat cortical nerve terminals. This release inhibition might be linked to the activation of presynaptic cannabinoid CB1 receptors and the suppression of the protein kinase A pathway.
Italian and Dutch PEA
Palmitoylethanolamide is especially in Italy and the USA at the moment hot for the treatment of glaucoma. We prefer treatment either with the Italian PEA tablets, based on PEA-um or PEA-m, or by administrating the Dutch PEA capsules containing PEA-opt. Dutch capsules do not contain any chemical excipients and are 100% pure in vegetarian capsules.
Only for these the Dutch and the Italian formulations long term safety and efficacy data gathered under the supervision of MDs are available. And only for these formulations (PEA-um, PEA-m and PEA-opt) there are currently data available proving that after intake PEA levels in the body significantly rise. Such data do not exist for me-too PEA formulations.
Palmitoylethanolamide inhibits glutamate release in rat cerebrocortical nerve terminals.
Lin TY, Lu CW, Wu CC, Huang SK, Wang SJ.
Int J Mol Sci. 2015 Mar 11;16(3):5555-71. doi: 10.3390/ijms16035555.