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Biomedical subjects

E C Murphy

Publications and source records attributed to E C Murphy.

82 records · Page 5Linked to original sources
PubMed1979

Presynaptic effect of I.V. anaesthetic agents at the neuromuscular junction.

The effect of Althesin, diazepam, ketamine, propanidid and thiopentone on the release of acetylcholine was tested at the mouse neuromuscular junction. Althesin, diazepam and thiopentone increased the quantal content of the end-plate potential. Ketamine at low concentration (3.6 micromol litre-1) had a similar effect, but at high concentration (116.7 micromol litre-1) quantal content decreased sharply. Propanidid and cremophor EL did not affect quantal content. The increase in quantal content antagonized the effect of postsynaptic depression on the amplitude of the end-plate potential. The lack of enhancement of acetylcholine release appears to explain the in vitro interaction of propanidid with tubocurarine. The diversity of presynaptic actions of these drugs makes it unlikely that this is an important mechanism in producing anaesthesia.

Acetylcholine↗
PubMed1978

Tryptic peptide analyses of polypeptides generated by premature termination of cell-free protein synthesis allow a determination of the Rauscher leukemia virus gag gene order.

Translation of Rauscher murine leukemia virus (R-MuLV) 35S RNA in an mRNA-dependent cell-free protein-synthesizing system yields polypeptides identical to authentic Pr65gag, the R-MuLV gag precursor, and Pr200gag-pol, the precursor to the R-MuLV reverse transcriptase. In addition to these polypeptides, the cell-free product contains a family of polypeptides of less than 65,000 molecular weight which appear to be generated by premature termination of protein synthesis within the viral gag gene. We compared the tryptic maps of several of these less than 65,000-molecular-weight premature termination polypeptides with that of full-size Pr65gag and found a progressive loss of tryptic peptides which could be assigned to known R-MuLV gag proteins. A 40,000-molecular-weight fragment, P40gag, lacked p10 and part of p30, placing p10 at the C terminus pf Pr65gag and p30 ajacent to it. Fragments of 33,000 (P33gag) and 27,000 to 28,000 (P27/28gag) molecular weight showed a successive loss of additional p30 tryptic peptides, but no loss of either p15 or p12. An 18,000-molecular-weight fragment lost p12 but retained p15. These data suggest an R-MuLV gag gene order of NH2-p15-p12-p30-p10-COOH.

Genes, Viral↗