Inhibitory Effect of 8-Azaguanine on the Development of Tolerance in the Analgesic Action of Morphine

Hydroxylamine interferes with the behavioral response to morphine dependence in mice

“…Hydroxylamine may react with this active DNA, change its transcription and translation and thus interfere with the metabolic ada pta tion. Our experiments are comparable with those of Cohen et al (1965), Yamamoto et al (1967), Smith et al (1966), Way et al (1968), Feinberg & Cochin (1969, and Loh et al (1969), which demonstrated that the development of morphine tolerance and dependence may be blocked by actinomycin D, puromycin, cycloheximide, etc. The main difference between their observations and ours is that we blocked the developed existing dependence ex post.…”

5‐Hydroxytryptamine‐mediated effects of nicotine on endogenous GABA efflux from guinea‐pig cortical slices

“…Indeed, the inversion of nicotinemediated GABA facilitation into inhibition caused by methysergide, suggests that high nicotine concentrations could release so much 5-HT as to increase GABA efflux through excitatory methysergide-sensitive receptors, not involved in the in vivo effects. The lack of any facilitation by nicotine, even if given at high doses in the whole animal (Beani et al, 1991), might depend on the relatively low concentrations attained in the brain (Yamamoto et al, 1967;Rosencrans & Schechter, 1972). That the effects ofnicotine in vivo differ from those seen in cortical slices is also confirmed by the lack of any influence of naloxone in nicotine-treated slices, whereas the inhibitory control operated by the endogenous opioids on GABA release is well documented in freely moving animals (Beani et al, 1991).…”

6-Isopropyl-5-methoxy-3-phenyl-3H-1,2,3-triazolo[4,5-d]pyrimidin-7(6H)-one

“…Fpr the biological activity of 8-azaguanine derivatives, see: Roblin et al (1945); Ding et al (2004); Mitchell et al (1950); Levine et al (1963); Montgomery et al (1962); Yamamoto et al (1967); Bariana (1971); Holland et al (1975). For related structures, see: Chen & Shi (2006); Ferguson et al (1998); Li et al (2004); Maldonado et al (2006); Wang et al (2006); Xiao & Shi (2007); Zeng et al (2006Zeng et al ( , 2009 Table 1 Hydrogen-bond geometry (Å , ).…”

“…The derivatives of heterocycles containing 8-azaguanine system, which are well known bioisosteres of guanine, are of great importance because of their remarkable biological properties, such as antimicrobial or antifungal activities (Roblin et al, 1945;Ding et al, 2004), encephaloma cell inhibitor (Mitchell et al, 1950;Levine et al, 1963), antileukemie (Montgomery et al, 1962), hypersusceptibility inhibitor and acesodyne activities (Yamamoto et al, 1967;Bariana, 1971;Holland et al, 1975).…”