Glutamic Acid/pharmacokinetics; Neuroprotective Agents/isolation & purification; Neuroprotective Agents/pharmacology; Spider Venoms/isolation & purification; Tissue Extracts/pharmacology; Animals; Brazil; Carbon Isotopes; Cerebral Cortex/cytology; Chromatography, High Pressure Liquid/methods; Chromatography, Ion Exchange; Disease Models, Animal; Dose-Response Relationship, Drug; Glaucoma/drug therapy; Glaucoma/physiopathology; Glutamic Acid/drug effects; Glutamic Acid/metabolism; Ion Channels/drug effects; Ion Channels/metabolism; Ion Channels/physiopathology; Male; Neuroprotective Agents/chemistry; Rats; Rats, Wistar; Receptors, Metabotropic Glutamate/drug effects; Receptors, Metabotropic Glutamate/physiology; Retina/drug effects; Retina/pathology; Retina/ultrastructure; Spider Venoms/chemistry; Spider Venoms/pharmacology; Spiders; Synaptosomes/drug effects; Synaptosomes/metabolism; Tritium; gamma-Aminobutyric Acid/drug effects; gamma-Aminobutyric Acid/metabolism; gamma-Aminobutyric Acid/pharmacokinetics