Expression of single calcium channels in Xenopus oocytes after injection of mRNA from rat heart

Oocytes of Xenopus laevis, after microinjection with mRNA from rat heart, display typical high-threshold calcium (Ca) whole cell currents. To prepare to study structure-function relationships of the cardiac Ca channel molecule, we examined the fidelity of expression of biophysical and pharmacological properties at the molecular level. Cell-attached gigaseal recordings in five K-depolarized oocytes injected with adult rat heart mRNA showed single channel Ba currents with mean amplitude 1.3-1.5 pA at 0 mV, slope conductance 18-25 pS, and extrapolated reversal potential 57-68 mV. Openings were predominantly brief (mean 1.2 ms) but longer openings (mean 9 ms) were greatly enhanced in 10(-6) M BAY-K 8644, increasing the ensemble average current at 0 mV by more than fivefold. These features are typical of high-threshold cardiac Ca channels. In two patches from one injected oocyte, we saw multiple Ca channel conductances, as recently observed in other preparations. We conclude that X. laevis oocytes injected with adult rat heart mRNA produce high-threshold cardiac Ca channels with molecular properties identical to native cells.

Expression of single calcium channels in Xenopus oocytes after injection of mRNA from rat heart

Page H985: J. R. Moorman, Z. Zhou, G. E. Kirsch, A. E. Lacerda, J. M. Caffrey, D. M.-K. Lam, R. H. Joho, and A. M. Brown. “Expression of single calcium channels in Xenopus oocytes after injection of mRNA from rat heart.” Page H991: the following should have been included in the acknowledgements: We are grateful to John Leonard and Terry Snutch for their help and advice with the oocyte expression system.

Efficacy of vaccination with Skinner vaccine towards the prevention of herpes simplex virus induced cervical carcinoma in an experimental mouse model

The incidence of cervical carcinoma, which had been induced by vaginal application of inactivated herpes simplex virus type 2 (HSV-2) with 20% croton oil, was significantly reduced in mice prevaccinated with the Skinner herpes vaccine. There was evidence of an immunological response in both vaccinated and unvaccinated mice.

Effect of chronic ethanol consumption on activation of nitrosopyrrolidine to a mutagen by rat upper alimentary tract, lung, and hepatic tissue

Tissues derived from male Sprague-Dawley rats which had been pair-fed isocaloric ethanol or carbohydrate control diets for 4 weeks were used to determine the effect of chronic ethanol exposure on the activation of the smoking and diet-associated procarcinogen nitrosopyrrolidine (NPY). Microsomal preparations from lungs and liver and S9 fractions from alimentary tract mucosa were tested for their capacity to activate NPY to a mutagen by the Ames Salmonella assay. Chronic ethanol exposure resulted in an increased capacity to activate NPY by microsomes derived from liver, lungs, and esophagus but not from stomach. The three tissues in which enhanced activation of NPY was observed in the present study also have been noted in epidemiological studies to be target sites of alcohol abuse-associated increased cancer risk. The results presented here suggest that dietary ethanol's effect on carcinogen metabolism may be responsible, at least in part, for the increased cancer risk observed in chronic alcohol abusers.