The R100Q mutation of the GABA(A) alpha(6) receptor subunit may contribute to voluntary aversion to ethanol in the sNP rat line.

We have investigated the GABA(A) alpha(6) subunit molecular composition in two rat lines selectively bred for high or low ethanol preference and consumption, namely Sardinian alcohol-preferring (sP) and Sardinian non-alcohol-preferring (sNP) rats, which have been bred at the University of Cagliari, Italy, since 1981. A total of 27 sP, 22 sNP and 25 control rats belonging to five other different strains, were studied by direct sequencing and amplification refractory mutation system analysis. Among the sNPs, only one was found to be normal, 11 heterozygotes, and 10 homozygotes for the G-->A substitution in codon 100, the same R100Q point mutation previously described in Alcohol Non Tolerant rats, while no other animal showed any mutated allele. Pharmacological studies have extensively demonstrated that this substitution in the mature peptide changes the benzodiazepine-insensitive receptor to a sensitive one. In order to test the functional significance of this mutation in native cerebellar GABA(A) receptors, selective breeding from Q/R rats was employed to obtain a sufficient number of R/R homozygotes. Xenopus laevis oocytes were then injected with cerebellar synaptosomes extracted from Q/Q, R/Q and R/R sNP rats. Consistently, utilizing the two-electrode voltage-clamp technique, GABA-evoked currents mediated by GABA(A) receptors containing the mutated alpha(6) subunit were potentiated by diazepam with about a two-fold increased potency, as compared to receptors containing the wild-type, benzodiazepine-insensitive alpha(6) subunit. Our data show for the first time that a mutated GABA(A) alpha(6) receptor subunit segregates in a rat line which voluntarily avoids alcohol consumption, and further support a possible involvement of the GABA(A) receptor containing a mutated alpha(6) subunit in the genetic predisposition to alcohol preference.

A strategy for fragile-X carrier screening.

Fragile-X syndrome is due to an expression of CGG trinucleotide repeats in the 5' untranslated region of the FMR1 gene and it is the most common cause of heritable X-linked mental retardation. Until now, the disease and the carrier state were diagnosed by Southern blotting or PCR-based methods. Southern blotting is an expensive, time-consuming, and radioisotope-based method that cannot easily be used for routine screening of an at-risk population. Nonradioisotopic PCR methods do not identify full mutated alleles, nor do they discriminate between alleles in the normal range that differ only by one or two CGG repeats. Therefore, two normal alleles with only a small difference in size, cannot be differentiated after PCR in Metaphor agarose or acrylamide gels. To define the genotype, it is necessary to perform Southern blot analysis. In this paper, we present a new strategy which, because of its simplicity, can be applied to large-scale fragile-X carrier screening of at-risk females.

Sulfone derivatives with anti-HIV activity.

Following the discovery of anti-HIV properties of suramin great efforts were devoted to design novel NNRT agents with the aims to find novel drugs for the clinical therapeutic management of AIDS. Sulfone and sulfonamide derivatives were studied by NCI at Bethesda as potential anti-HIV-1 agents and nitrophenyl phenyl sulfone (NPPS) was selected as lead compound for further investigations. At the same time Merck Laboratories discovered L-737,126, a potent indolyl aryl sulfone with inhibitory activity against reverse transcriptase. These studies stimulated novel search in the sulfone series and both diarylsulfones and cyclic sulfone derivatives were investigated. Our decennial interest in chemotherapeutic agents containing a pyrrole ring pulsed us to synthesize and test as anti-HIV-1 agents a number of pyrryl aryl sulfones (PASs), pyrrolobenzothiadiazepine (PBTDs) and pyrrolobenzothiazepine related sulfones. The new sulfone derivatives inhibit selectively HIV-1 and were inactive against HIV-2. Most of them were as active as, if not more active than, nevirapine.

Acyclic glycosidopyrroles analogues of ganciclovir: synthesis and biological activity.

Acyclic glycosidopyrroles of type 3 were synthetized in good overall yields, according to the Scheme. When evaluated for antiviral activity against DNA and RNA viruses, only compound in which R1 = R2 = Ph, R3 = NH2 was found to inhibit the HIV-1 replication at concentrations that were not cytotoxic for MT-4 cells.