Parawixin2 Protects Hippocampal Cells in Experimental Temporal Lobe Epilepsy.

Epilepsy is considered as one of the major disabling neuropathologies. Almost one third of adult patients with temporal lobe epilepsy (TLE) do not respond to current antiepileptic drugs (AEDs). Additionally, most AEDs do not have neuroprotective effects against the inherent neurodegenerative process underlying the hippocampal sclerosis on TLE.

Enhancing glutamate transport: mechanism of action of Parawixin1, a neuroprotective compound from Parawixia bistriata spider venom.

Previous studies have shown that a compound purified from the spider Parawixia bistriata venom stimulates the activity of glial glutamate transporters and can protect retinal tissue from ischemic damage. To understand the mechanism by which this compound enhances transport, we examined its effects on the functional properties of glutamate transporters after solubilization and reconstitution in liposomes and in transfected COS-7 cells. Here, we demonstrate in both systems that Parawixin1 promotes a direct and selective enhancement of glutamate influx by the EAAT2 transporter subtype through a mechanism that does not alter the apparent affinities for the cosubstrates glutamate or sodium.

Anticonvulsant and anxiolytic activity of FrPbAII, a novel GABA uptake inhibitor isolated from the venom of the social spider Parawixia bistriata (Araneidae: Araneae).

This study was aimed at determining the effects of FrPbAII (174 Da), a novel isolated component from Parawixia bistriata spider venom, in the CNS of Wistar rats. Considering that FrPbAII inhibits the high affinity GABAergic uptake in a dose-dependent manner, its anxiolytic and anticonvulsant effects were analyzed in well-established animal models. Injection of FrPbAII in the rat hippocampus induced a marked anxiolytic effect, increasing the occupancy in the open arms of the elevated plus maze (EC(50)=0.

Behavioral effects of bicuculline microinjection in the dorsal versus ventral hippocampal formation of rats, and control of seizures by nigral muscimol.

This work aims to describe behavioral/electroencephalographic (EEG) seizures induced by bicuculline microinjection intracerebroventricularly (ICV) and in the dorsal hippocampal formation (DHF) or ventral hippocampal formation/amygdala area (VHF-AMY). We also test if GABAergic manipulation in the substantia nigra pars reticulata (SNPR) is capable of controlling those seizures. ICV injection of bicuculline induced a progressive sequence of convulsive responses, jumps and escapes from the open-field.

Purification of a neuroprotective component of Parawixia bistriata spider venom that enhances glutamate uptake.

(1) In this study, we examined the effects of crude venom from the spider Parawixia bistriata on glutamate and GABA uptake into synaptosomes prepared from rat cerebral cortex. Addition of venom to cortical synaptosomes stimulated glutamate uptake and inhibited GABA uptake in a concentration-dependent manner. (2) The venom was fractionated using reverse-phase high-performance liquid chromatography on a preparative column.