Functional Aspects of Neuroprotective Effects of New Salts and Compositions of Baclofen in the Convulsive Syndrome Caused by Electroshock

Trio-Drug Combination of Sodium Valproate, Baclofen and Thymoquinone Exhibits Synergistic Anticonvulsant Effects in Rats and Neuro-Protective Effects in HEK-293 Cells

Epilepsy is a chronic brain disorder, with anti-epileptic drugs (AEDs) providing relief from hyper-excitability of neurons, but largely failing to restrain neurodegeneration. We investigated a progressive preclinical trial in rats, whereby the test drugs; sodium valproate (SVP; 150 and 300 mg/kg), baclofen (BFN; 5 and 10 mg/kg), and thymoquinone (THQ; 40 and 80 mg/kg) were administered (i.p, once/day for 15 days) alone, and as low dose combinations, and subsequently tested for antiseizure and neuroprotective potential using electrical stimulation of neurons by Maximal electroshock (MES). The seizure stages were monitored, and hippocampal levels of m-TOR, IL-1β, IL-6 were measured. Hippocampal histopathology was also performed. Invitro and Insilco studies were run to counter-confirm the results from rodent studies. We report the synergistic effect of trio-drug combination; SVP (150 mg/kg), BFN (5 mg/kg) and THQ (40 mg/kg) against generalized seizures. The Insilco results revealed that trio-drug combination binds the Akt active site as a supramolecular complex, which could have served as a delivery system that affects the penetration and the binding to the new target. The potential energy of the ternary complex in the Akt active site after dynamics simulation was found to be -370.426 Kcal/mol, while the supramolecular ternary complex alone was -38.732 Kcal/mol, with a potential energy difference of -331.694 Kcal/mol, which favors the supramolecular ternary complex at Akt active site binding. In addition, the said combination increased cell viability by 267% and reduced morphological changes induced by Pentylenetetrazol (PTZ) in HEK-293 cells, which indicates the neuroprotective property of said combination. To conclude, we are the first to report the anti-convulsant and neuroprotective potential of the trio-drug combination.

Anticonvulsive profile of two GABAB receptor antagonists on acute seizure mice models

INTRODUCTION

DL-3-hydroxy-3-phenylpentanamide (HEPP) and DL-3-hydroxy-3-(4'chlorophenyl)-pentanamide (Cl-HEPP) are phenyl-alcohol-amides that are metabotropic GABAB receptor (MGBR) antagonists and protective against absence seizures. This study aims to further characterize the anticonvulsant profile of these drugs.

METHODS

HEPP and Cl-HEPP were evaluated in various standardized acute seizure and toxic tests in female Swiss-OF1 mice.

RESULTS

Toxicities of HEPP and Cl-HEPP were limited; doses up to 30 mg/kg did not result in hypothermia, reduced spontaneous locomotor activity, or failure of the rotarod test, with doses >15 mg/kg potentiating pentobarbital-induced sleep. In maximal electroshock-induced seizures, 20 mg/kg Cl-HEPP protected 100 % of mice; lower doses shortened post-ictal recovery. Seizure protection occurred against subcutaneous pentylenetetrazole and picrotoxin, being limited against N-methyl-d-aspartate. In bicuculline test, clonic or fatal tonic seizures were decreased, onset delayed, and recovery improved; ED₅₀ values (dose protecting 50 % of the animals) were 37.5 and 25 mg/kg for HEPP and Cl-HEPP, respectively. In magnesium deficiency-dependent audiogenic seizures (MDDAS), ED₅₀ values were 3 and 8 mg/kg for Cl-HEPP and HEPP, respectively. The components of MDDAS (latency, wild running, seizure, and recovery phases) in unprotected animals were only minimally affected by near ED₅₀ doses of Cl-HEPP and HEPP.

DISCUSSION

HEPP and, to a greater extent, Cl-HEPP provide anti-seizure protections in several acute seizure tests in mice at nontoxic doses. These results are consistent with the action of these drugs on diverse molecular targets directly resulting from their MGBR antagonistic properties. However, other mechanisms might occur possibly for the protection given in the MES test. Finally, a similarity in the modulation of MDDAS components between the two phenyl alcohol amides and ethosuximide could also be based on the MGBR antagonistic properties of the former, given the recently re-evaluated therapeutic relevant targets of the latter.

Baclofen Protects Primary Rat Retinal Ganglion Cells from Chemical Hypoxia-Induced Apoptosis Through the Akt and PERK Pathways

Retinal ganglion cells (RGCs) consume large quantities of energy to convert light information into a neuronal signal, which makes them highly susceptible to hypoxic injury. This study aimed to investigate the potential protection by baclofen, a GABA_B receptor agonist of RGCs against hypoxia-induced apoptosis. Cobalt chloride (CoCl₂) was applied to mimic hypoxia. Primary rat RGCs were subjected to CoCl₂ with or without baclofen treatment, and RNA interference techniques were used to knock down the GABA_B2 gene in the primary RGCs. The viability and apoptosis of RGCs were assessed using cell viability and terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling (TUNEL) assays, Hoechst staining, and flow cytometry. The expression of cleaved caspase-3, bcl-2, bax, Akt, phospho-Akt, protein kinase RNA (PKR)-like ER kinase (PERK), phospho-PERK, eIF2α, phospho-eIF2α, ATF-4 and CCAAT/enhancer-binding protein homologous protein (CHOP) were measured using western blotting. GABA_B2 mRNA expression was determined using quantitative real-time polymerase chain reaction (qRT-PCR) analysis. Our study revealed that CoCl₂ significantly induced RGC apoptosis and that baclofen reversed these effects. CoCl₂-induced reduction of Akt activity was also reversed by baclofen. Baclofen prevented the activation of the PERK pathway and the increase in CHOP expression induced by CoCl₂. Knockdown of GABA_B2 and the inactivation of the Akt pathway by inhibitors reduced the protective effect of baclofen on CoCl₂-treated RGCs. Taken together, these results demonstrate that baclofen protects RGCs from CoCl₂-induced apoptosis by increasing Akt activity and by suppressing the PERK pathway and CHOP activation.

Comparison of Nootropic and Neuroprotective Features of Aryl-Substituted Analogs of Gamma-Aminobutyric Acid

GABA analogs containing phenyl (phenibut) or para-chlorophenyl (baclofen) substituents demonstrated nootropic activity in a dose of 20 mg/kg: they improved passive avoidance conditioning, decelerated its natural extinction, and exerted antiamnestic effect on the models of amnesia provoked by scopolamine or electroshock. Tolyl-containing GABA analog (tolibut, 20 mg/kg) exhibited antiamnestic activity only on the model of electroshock-induced amnesia. Baclofen and, to a lesser extent, tolibut alleviated seizures provoked by electroshock, i.e. both agents exerted anticonvulsant effect. All examined GABA aryl derivatives demonstrated neuroprotective properties on the maximum electroshock model: they shortened the duration of coma and shortened the period of spontaneous motor activity recovery. In addition, these agents decreased the severity of passive avoidance amnesia and behavioral deficit in the open field test in rats exposed to electroshock. The greatest neuroprotective properties were exhibited by phenyl-containing GABA analog phenibut.