Biomedical subjects

David R Burt

Publications and source records attributed to David R Burt.

4 recordsLinked to original sources

PubMed2005

Alpha subunit position and GABA receptor function.

GABA(A) (gamma-aminobutyric acid type A) receptors are ligand-gated ion channels composed of five subunits, generally two alphas, two betas, and a gamma2. Recent research in which sets of subunits containing alpha1 or alpha6 subunits were artificially linked has revealed the importance of subunit position in determining GABA(A) receptor function. Sensitivity to benzodiazepines depended on juxtaposition of an alpha1 subunit with the gamma2 subunit, whereas sensitivity to furosemide depended only on the presence of an alpha6 subunit and not on its specific location. The major utility of the linked subunit approach is to provide a mechanism for discovering the functional signatures of defined subunit arrangements, and thus a route to identifying such arrangements in vivo.

Animals↗

PubMed2005

Acute reperfusion therapy in acute myocardial infarction.

The ECG classification of acute myocardial infarctions has had a profound influence on the treatment of patients with AMI. Deciding whether a patient has ST-segment elevations or a new left bundle branch block or neither of these findings on ECG launches the treating physician down two different treatment pathways: patients with ST-elevation MI need to be assessed for immediate re-perfusion therapy, whereas patients with non-ST-elevation MI are best treated with aggressive medical management without acute reperfusion.

Humans↗

PubMed2003

Reducing GABA receptors.

A number of important drugs act on GABA(A) receptors, pentameric GABA-gated chloride channels assembled from among 19 known subunits. In trying to discover the roles in the brain of the subunits and their combinations, with the goal of developing more selective drugs, one tool has been to reduce expression of the subunits and examine the functional consequences. After briefly examining the properties of GABA(A) receptors, this review surveys the means available for receptor subunit reduction, and some of the observations to which their application has led. The methods discussed include radiation-induced deletion, gene knockout, knock-in mutations, antisense, ribozymes, RNA interference, dominant negative constructs, and transcriptional regulation, e.g., via decoy oligonucleotides.

Animals↗

PubMed2002

Alternative splicing of the GABA(A) receptor alpha 4 subunit creates a severely truncated mRNA.

GABA(A) receptors, important sites of drug action, are chloride channels composed of 5 subunits chosen from among 19 or more. Alternative splicing for alpha 5, alpha 6, and rho 1 subunits results in truncated proteins which appear to lack function. We report a similar, relatively common (about 20%) form of alternative splicing of the alpha 4 subunit mRNA in mice and humans which, remarkably, creates a severely truncated message containing only the first two and last coding exons, with a frameshift in between. The only apparent translation product includes a short piece (39 amino acids) of the N-terminus right after the signal peptide. The splicing was developmentally and regionally regulated; the highest proportions of truncated alpha 4 mRNA, about 40%, were observed in embryonic day 18 whole brain and adult cerebellum. The truncated mRNA, when coexpresssed in human embryonic kidney (HEK) 293 cells with the complete alpha 4 subunit and beta1 and gamma 2 S subunits, reduced observed GABA currents without kinetic alterations. No such effect of truncated alpha 4 was observed with alpha1 subunit-containing receptors. Thus, the truncated alpha 4 N-terminus may play a post-translational regulatory role in intracellular folding/glycosylation/assembly of the alpha 4 subunit.

Alternative Splicing↗