Pertussis toxin blocks presynaptic glutamate receptors--a novel 'glutamateB' receptor in the lobster neuromuscular synapse.
Topical application of L-glutamate to the neuromuscular synapse of the lobster walking leg induced K+-dependent hyperpolarization in the presynaptic membrane. This presynaptic glutamate potential (PGP) was insensitive to Joro spider toxin (JSTX), a spider toxin which specifically blocks the postsynaptic glutamate receptor, but was blocked by pertussis toxin island activating protein (IAP) in a dose-dependent manner. IAP had little effect on the resting conductance channels in pre- and postsynaptic membranes. GTP gamma S, a hydrolysis-resistant analogue of GTP, reduced the PGP supporting the involvement of G-protein in generation of K+ activation. The results suggest that a new type of glutamate receptor exists in the presynaptic membrane in the crustacean neuromuscular synapse.
D000818:Animals; D005971:Glutamates / Q000502:physiology; D018698:Glutamic Acid; D016244:Guanosine 5'-O-(3-Thiotriphosphate); D006160:Guanosine Triphosphate / Q000031:analogs & derivatives / Q000494:pharmacology; D066298:In Vitro Techniques; D008564:Membrane Potentials / Q000187:drug effects; D008121:Nephropidae / Q000502:physiology*; D009469:Neuromuscular Junction / Q000187:drug effects* / Q000502:physiology; D009498:Neurotoxins / Q000494:pharmacology; D037342:Pertussis Toxin; D017470:Receptors, Glutamate; D017981:Receptors, Neurotransmitter / Q000145:classification / Q000187:drug effects* / Q000502:physiology; D013873:Thionucleotides / Q000494:pharmacology; D010566:Virulence Factors, Bordetella / Q000494:pharmacology*
D005971:Glutamates; D009498:Neurotoxins; D017470:Receptors, Glutamate; D017981:Receptors, Neurotransmitter; D013873:Thionucleotides; D010566:Virulence Factors, Bordetella; D016244:Guanosine 5'-O-(3-Thiotriphosphate); D018698:Glutamic Acid; D006160:Guanosine Triphosphate; D037342:Pertussis Toxin