Effects of cicutoxin and related polyacetylenes from Cicuta virosa on neuronal action potentials: a comparative study on the mechanism of the convulsive action.

Cicutoxin, the convulsant principle of water hemlock, Cicuta virosa L., and the related polyacetylenes isocicutoxin, cicudiol, cicutol, falcarindiol, and falcarinol (20-100 micromol/l) were investigated concerning their influence on electrophysiological parameters using the giant cell RPD1 of the right parietal ganglion of the pond snail, Lymnaea stagnalis L., as a model neurone.

[The effect of cholesterol on membrane potentials, proliferation and migration of cultivated endothelial cells].

The influence of cholesterol added as cholesterol containing liposomes [sphingomyelin/cholesterol (1: 1; mol/mol)] or as cholesterol suspensions on cultured bovine aortic endothelial cells was investigated. 10(-6) mol/l cholesterol enhanced membrane potential, 10(-5) mol/l caused depolarisation. The proliferation of the cells was dependent on the concentration influenced in opposite directions too.

[The effect of alkyl-lysophospholipids and membrane potentials, proliferation and migration of isolated calf aorta endothelial cells].

Cancerostatical active synthetic alkyl-lysophospholipids were examined with regard to their effects on membrane potential, proliferation and migration of isolated endothelial cells. In sublytic concentrations all alkyl-lysophospholipids tested caused a hyperpolarization of the membrane of endothelial cells. The effect of alkyl-lysophospholipids on proliferation of endothelial cells was dependent on the serum supplement.

[Criteria for the use of the linear allothermal short-time test in predicting stability (author's transl)].

Three selected model substances of varying activation energy (naphazoline, 109 kJ/mole; acetylsalicylic acid, 72 kJ/mole; and phenobarbital, 60 kJ/mole) were studied to determine the conditions under which the allothermal short-time test according to Zoglio (linear increase in temperature) will yield stability predictions which are consistent with those provided by the isothermal short- or long-time test. The error of the determination method should be less than or equal to 1%. It is advantageous to use for the calculation as many data as the analytical facilities will permit to obtain.