Effects of the Paratemnus elongatus pseudoscorpion venom in the uptake and binding of the L-glutamate and GABA from rat cerebral cortex.
L-Glu is the most important and widespread excitatory neurotransmitter of the vertebrates. Four types of receptors for L-glu have been described. This neurotransmitter modulates several neuronal processes, and its dysfunction causes chronic and acute diseases. L-Glu action is terminated by five distinct transporters. Antagonists for these receptors and modulators of these transporters have anticonvulsant and neuroprotective potentials, as observed with the acylpoliamines and peptides isolated from spiders, solitary and social wasp venoms. On the other hand, the major inhibitory neurotransmitter in mammalian nervous tissue is the GABA. Drugs that enhance GABA neurotransmission comprise effective approaches to protecting the brain against neuronal injury. Is this study, we demonstrate for the first time the inhibition of the [3H]L-glu binding to its specific sites in synaptosomal membranes from rat cerebral cortex, produced by 0.027 U of Paratemnus elongatus venom (EC50). The venom of P. elongatus changes Km and Vmax into the high affinity uptake of the L-glu and decreases Km and Vmax into the parameters of the GABA uptake from rat synaptosomes. This leads us to speculate on the possible presence of selective and specific compounds in this venom that act in L-glu and GABA dynamics, and therefore, that can serve as tools and new drug models for understanding these neurotransmissions.
Department of Biology, Neurobiology and Venoms Laboratory, Faculty of Philosophy, Sciences and Literature of Ribeirão Preto, University of São Paulo, 14040-901 Ribeirão Preto, São Paulo, Brazil. wagnerf@usp.br
Wagner Ferreira dos
WF
Santos
Joaquim
J
Coutinho-Netto
D000818:Animals; D001692:Biological Transport / Q000187:drug effects; D002540:Cerebral Cortex / Q000378:metabolism*; D018698:Glutamic Acid / Q000378:metabolism*; D008297:Male; D051381:Rats; D017208:Rats, Wistar; D015398:Signal Transduction / Q000187:drug effects*; D013111:Spider Venoms / Q000633:toxicity*; D013574:Synaptosomes / Q000378:metabolism*; D005680:gamma-Aminobutyric Acid / Q000378:metabolism*
D013111:Spider Venoms; D018698:Glutamic Acid; D005680:gamma-Aminobutyric Acid