The effects of JM-20 on the glutamatergic system in synaptic vesicles, synaptosomes and neural cells cultured from rat brain

Abstract

JM-20 (3-ethoxycarbonyl-2-methyl-4-(2-nitrophenyl)-4,11-dihydro-1H-pyrido[2,3-b][1,5]benzodiazepine) is a novel benzodiazepine dihydropyridine hybrid molecule, which has been shown to be a neuroprotective agent in brain disorders involving glutamate receptors. However, the effect of JM-20 on the functionality of the glutamatergic system has not been investigated. In this study, by using different in vitro preparations, we investigated the effects of JM-20 on (i) rat brain synaptic vesicles (L-[(3)H]-glutamate uptake, proton gradient built-up and bafilomycin-sensitive H(+)-ATPase activity), (ii) rat brain synaptosomes (glutamate release) and (iii) primary cultures of rat cortical neurons, astrocytes and astrocyte-neuron co-cultures (L-[(3)H]-glutamate uptake and glutamate release). We observed here that JM-20 impairs H(+)-ATPase activity and consequently reduces vesicular glutamate uptake. This molecule also inhibits glutamate release from brain synaptosomes and markedly increases glutamate uptake in astrocytes alone, and co-cultured neurons and astrocytes. The impairment of vesicular glutamate uptake by inhibition of the H(+)-ATPase caused by JM-20 could decrease the amount of the transmitter stored in synaptic vesicles, increase the cytosolic levels of glutamate, and will thus down-regulate neurotransmitter release. Together, these results contribute to explain the anti-excitotoxic effect of JM-20 and its strong neuroprotective effect observed in different in vitro and in vivo models of brain ischemia.

Impairment of GABAergic system contributes to epileptogenesis in glutaric acidemia type I

“…Synaptosome preparations were obtained from the brains of Gcdh −/− and Gcdh +/+ mice as described previously . One aliquot was used immediately for neurotransmitter release assay and the other was stored in −20°C for Western blot analysis.…”

Preventive and therapeutic effects of JM-20 on paclitaxel-evoked painful peripheral neuropathy in rats

“…In addition, the long-term therapeutic effect of this compound suggests its ability to modulate synaptic plasticity. Considering that glutamatergic neurotransmission plays a pivotal role in central sensitization that occurs in NP, the regulatory effect of JM-20 on the glutamate homeostasis could be involved in this phenomenon (Latremoliere and Woolf, 2009;Nuñez-Figueredo et al, 2015). In line with these ideas, the downregulation of glutamate transporters in the spinal cord to the paclitaxel-induced hyperalgesia has been reported (Weng et al, 2005).…”

Neuroimmunology Research. A Report from the Cuban Network of Neuroimmunology

“…This paper showed that the treatment with JM-20 prevented the increase of the expression of pro-apoptotic signaling proteins, protecting neuronal loss and presumably cognitive impairment, and in this line of findings the authors suggested that JM-20 may prevent memory impairment via mitochondrial protection and the inhibition of the intrinsic apoptosis pathway, also suggesting a therapeutic benefit to neurodegenerative dementia like Alzheimer’s disease. The results on the regional effects of transient cerebral ischemia on astrocytes reactivity and the PI3K/Akt survival pathway, and the role of JM-20, were shown by Ramírez-Sánchez Jeney [ 50 , 51 ].…”