Purified Native Protein Extracted from the Venom of Agelena orientalis Attenuates Memory Defects in the Rat Model of Glutamate-Induced Excitotoxicity.

Abstract

Spider venom contains various peptides and proteins, which can be used for pharmacological applications. Finding novel therapeutic strategies against neurodegenerative diseases with the use of purified peptides and proteins, extracted from spiders can be greatly precious. Neurodegenerative diseases are rapidly developing and expanding all over the world. Excitotoxicity is a frequent condition amongst neuro-degenerative disorders. This harmful process is usually induced through hyper-activation of N-Methyl-D-Aspartate (NMDA) receptor, and P/Q-type voltage-gated calcium channels (VGCCs). The omega-agatoxin-Aa4b is a selective and strong VGCCblocker. This study aimed to investigate the effects of this blocker on the NMDA-induced memory and learning defect in rats. For this purpose, nineteen spiders of the funnel-weaver Agelena orientalis species were collected. The extracted venom was lyophilized andpurified through gel-filtration chromatography, and capillary electrophoresis techniques. Subsequently, mass spectrometry (HPLC-ESI-MS) was used for identification of this bio-active small protein. Afterward, the effect of the omega-agatoxin-Aa4b (2μg, intra-cornu ammonis-3 of the hippocampus) on the NMDA-induced learning and memory deficits in rats was evaluated. Learning and memory performances were evaluated by the use of passive avoidance test. For synaptic quantification and memory function the amount of calcium/calmodulin-dependent protein kinase ІІ (CaCdPKІІ) gene expression was measured using the Real-time PCR technique. To compare the experimental groups, hematoxylin and eosin (H&E) staining of hippocampus tissues was performed. Our results rendered that the omega-Agatoxin-Aa4b treatment can ameliorate and reverse the learning and memory impairment caused by NMDA-induced excitotoxicity in rat hippocampus.