Structure and synthesis of a potent glutamate receptor antagonist in wasp venom.

Abstract

A low molecular weight toxin isolated from the venom ofthe digger wasp Philanthus triangulum, first noted by T. Piek, is a potent antagonist of transmission at quisqualate-sensitive glutamate synapses of locust leg muscle. This philanthotoxin 433 (PTX-433) has been purified, chemically characterized, and subsequently synthesized along with two closely related analogues. It has a butyryl/tyrosyl/spermine sequence and a molecular weight of 435. Its two analogues, PTX-343 and PTX-334 (the numerals denoting the number of methylenes between the amino groups of the spermine moiety), are also active on the glutamate synapse of the locust leg muscle; PTX-334 was more potent and PTX-343 was less potent than the natural toxin. Such chemicals are useful for studying, labeling, and purifying glutamate receptors and may become models for an additional class oftherapeutic drugs and possibly insecticides. (19). The muscle apodeme was attached to a Grass FT 10-strain gauge with a short strand of Terylene, and the muscle was stretched to maximal body length. The total volume of the bath was about 0.5 ml, and the contents could be replaced within 1 s. The dissection and setting up proceAbbreviation: PTX, philanthotoxin. 4910The publication costs of this article were defrayed in part by page charge payment. This article must therefore be hereby marked "advertisement" in accordance with 18 U.S.C. §1734 solely to indicate this fact.

Removal of Synaptic Ca2+-Permeable AMPA Receptors during Sleep

“…We measured the contribution of CPAMPARs to synaptic transmission with philanthotoxin 74 (PhTx) (5 M) (Eldefrawi et al, 1988;Washburn and Dingledine, 1996). Occasional augmenting responses to PhTx were considered unspecific, and the data from these cells were excluded from additional analysis (Brackley et al, 1990).…”

The Effects of Conformational Constraints in the Polyamine Moiety of Philanthotoxins on AMPAR Inhibition

“…THF was distilled from Na/benzophenone immediately before use. 1 H NMR and 13 C NMR spectra were recorded at 400.14 MHz and 100.62 MHz, respectively, on a Bruker AMX 400 spectrometer, or at 300.06 MHz and 75.45 MHz, respectively, on a Varian Mercury Plus spectrometer, using CDCl3 or CD3OD as solvents and tetramethylsilane (TMS) as internal standard. Coupling constants (J values) are given in hertz (Hz), and multiplicities of 1 H NMR signals are reported as follows: s, singlet; d, doublet; t, triplet; q, quartet; p, pentet, sx, sextet; m, mulitplet; br, broad.…”

“…1 H NMR and 13 C NMR spectra were recorded at 400.14 MHz and 100.62 MHz, respectively, on a Bruker AMX 400 spectrometer, or at 300.06 MHz and 75.45 MHz, respectively, on a Varian Mercury Plus spectrometer, using CDCl3 or CD3OD as solvents and tetramethylsilane (TMS) as internal standard. Coupling constants (J values) are given in hertz (Hz), and multiplicities of 1 H NMR signals are reported as follows: s, singlet; d, doublet; t, triplet; q, quartet; p, pentet, sx, sextet; m, mulitplet; br, broad. High-resolution mass spectrometry (HRMS) measurements were performed on a Bruker APEX Qe Fourier transform mass spectrometer equipped with a 9.4 tesla superconducting cryomagnet, and an external electrospray ion source (Apollo II source).…”

“…[1,2] PhTX-433 and many of its synthetic analogues have been shown to have non-competitive inhibitory effects at both ionotropic glutamate receptors and nicotinic acetylcholine receptors. [3][4][5][6] In that respect PhTXs are attractive molecules to investigate further given that both of these receptor types are accepted as valid drug targets for a variety of neurodegenerative and other disorders of the central nervous system.…”

Philanthotoxin blocks quisqualate‐, AMPA‐ and kainate‐, but not NMDA‐, induced excitation of rat brainstem neurones in vivo

“…Philanthotoxin (PhTx), from the Egyptian digger wasp, Philanthus triangulum, is similar in structure and molecular weight to some of the above spider toxins, such as argiotoxin636 (ATX) and Joro spider toxin (JSTX). Similarly, PhTx also causes neuromuscular paralysis when injected into honeybees on which the wasp preys (Eldefrawi et al, 1988). Because of our interest in non-NMDA glutamate antagonists (Honore et al, 1988) and because the actions of arthropod toxin have shown variable selectivity on mammalian glutamate receptors (Jackson & Usherwood, 1988), we decided to investigate the effects of PhTx on responses of rat central neurones in vivo to excitatory amino acids.…”