RT Journal Article
SR Electronic
T1 Effects of Bis(2-chloroethyl)sulfide on ATP Receptor-Mediated Responses of the Rat Vas Deferens: Possible Relationship to Cytotoxicity
JF Journal of Pharmacology and Experimental Therapeutics
JO J Pharmacol Exp Ther
FD American Society for Pharmacology and Experimental Therapeutics
SP 299
OP 306
VO 285
IS 1
A1 Paul M. Lundy
A1 Thomas W. Sawyer
A1 Brian T. H
A1 and Robert Frew
YR 1998
UL http://jpet.aspetjournals.org/content/285/1/299.abstract
AB Extracellular ATP is a broad-spectrum cytotoxic agent that produces effects via cell surface P2 purinoceptors. The ligand-gated P2X purinoceptor subtype has very high sequence homology with theRP-2 gene, which encodes for apoptosis. The P2X RNA found in rat vas deferens is expressed preferentially by apoptotic thymocytes. P2X purinoceptor-mediated phasic (twitch) motor responses of the isolated rat vas deferens to neurogenic or exogenous ATP were rapidly, specifically and irreversibly potentiated by bis(2-chloroethyl)sulfide (HD 10-100 μM). Both untreated and HD-potentiated neurogenic responses were Ca++ dependent, blocked in the absence of Ca++ plus 0.1 mM EGTA, by the neuronal Ca++channel blocker ω-conotoxin-MVIIC (3 μM), by the P2 purinoceptor antagonist suramin (100 μM) and by tetrodotoxin (100 nM). HD also potentiated the effects of ATP on isolated guinea pig taenia caecum, where the nucleotide acts at G protein-coupled P2Y purinoceptor subtypes to cause relaxation. HD failed to inhibit the metabolism of ATP by ecto-ATPase in vas deferens or to cause the release of endogenous ATP. Potentiation of the twitch response to electric field stimulation by HD was attenuated or eliminated in tissues excised from rats previously challenged with topically applied HD, suggesting that HD absorbed into the systemic circulation had already effected maximal potentiation of ATP responses before in vitro testing. The physiological consequences of HD-induced potentiation of the extracellular actions of ATP are discussed in relation to apoptosis and necrosis. The American Society for Pharmacology and Experimental Therapeutics