The active form of local anesthetic drugs

Riassunto Il problema della forma attiva degli anestetici locali é stato studiato determinando l'effetto della tetracaina sul trasporto di Na, K, Ca, Mg in un modello di membrana. Poiché l'azione dell'anestetico é massima a pH acido, é probabile che il farmaco agisca in forma cationica.     

Effect of alkali cations on the interaction between detergents and erythrocyte membranes

Resumen Los distintos cationes alcalinos monovalentes (145 mM) y divalentes (100 mM) modifican marcadamente el grado de hemólisis de eritrocitos humanos provocado por Triton X-100 y por desoxicolato de Na (DOC). La serie de actividad con cationes monovalentes en hemólisis por Triton es K>Rb=Cs>NaLi, y por DOC es Li>Rb=Cs>K>Na. Por el contrario, el grado de solubilización de membranas eritrocitarias producido por Triton o DOC es independiente de los distintos cationes alcalinos.     

Fluorometric study of interaction between ACTH fragments and bovine adrenocortical membranes.

Corticotropin 1-24 and [Gly1]corticotropin1-18 amide increased the fluorescence of 1-anilinonaphthalene-8-sulfonate which bound to the bovine adrenocortical membranes. The two ACTH fragments interacted with the protein of the membranes and membranes and increased the net positive charge of the membranes.     

Influence of diuretics on renal calcium excretion

Zusammenfassung Die renale Kalziumausscheidung wird bei einmaliger i.v. Zufuhr von Aminophyllin, Furosemid, Etacrynsäure, Azetazolamid und Chlorothiazid erhöht. Dies kann nicht nur durch die erhöhte Natriumausscheidung erklärt werden, sondern muss mit dem direkten tubulären Kalziumtransport im Zusammenhang stehen.     

Partition coefficients of drugs in bilayer lipid membranes

The oil/water partition coefficient of drugs is widely accepted as a key parameter in drug design. The coefficients are usually determined using a bulk octanol phase to represent the lipid. The physiologically and pharmacologically relevant structure is, of course, the bilayer lipid membrane, but until now there has been no convenient means of measuring the partition coefficients of small molecules into a single bilayer. This paper demonstrates that the partition coefficient may be calculated from the change in membrane refractive index which occurs when a drug molecule partitions into the membrane. The refractive index is determined by an integratedoptics technique ideally suited to an ultra-thin structure such as a lipid bilayer.     

Biochemical studies of pigments from a pathogenic fungusMicrosporum cookei. V. Evidence for the transmembrane permeability of xanthomegnin across phospholipid bilayer membranes

Summary Direct evidence is provided for the transmembrane permeation of xanthomegnin across phospholipid bilayer mebranes using ascorbate-loaded liposomes. This process may be associated with an uncoupling effect on the oxidative phosphorylation of mitochondria.     

Biochemical studies of pigments from a pathogenic fungus Microsporum cookei. V. Evidence for the transmembrane permeability of xanthomegnin across phospholipid bilayer membranes.

Direct evidence is provided for the transmembrane permeation of xanthomegnin across phospholipid bilayer membranes using ascorbate-loaded liposomes. This process may be associated with an uncoupling effect on the oxidative phosphorylation of mitochondria.     

Postnatal variations of extracellular free calcium levels in the rat. Influence of undernutrition.

Ontogenetic changes in calcium activity were directly measured using an ion-selective micropipette in rat blood plasma and olfactory bulb extracellular fluid. Significant differences were observed according to the age and the nutritional state of the animal.     

Effect of clofibrate on the phospholipid biosynthesis in rat liver.

The effect of clofibrate on rat liver phospholipid biosynthesis was studied using 32P as a precursor. Phospholipid classes, levels and specific radioactivity were evaluated. Significant increases in levels of phosphatidylethanolamine and phosphatidylcholine were found and could account for the observed increase in total phospholipids. Specific activity of phosphatidylserine increased and that of phosphatidylethanolamine decreased. This fact suggests that clofibrate seems to alter the systems engaged in the transformation occurring within the different classes of phospholipids but not the de novo biosynthesis.     

Postnatal variations of extracellular free calcium levels in the rat. Influence of undernutrition

Summary Ontogenetic changes in calcium activity were directly measured using an ion-selective micropipette in rat blood plasma and olfactory bulb extracellular fluid. Significant differences were observed according to the age and the nutritional state of the animal.We are grateful to Prof. W. Simon, Swiss Federal Institue of Technology, for providing the neutral carrier Ca²⁺ ion exchanger.     

Influence of anticholinergic-antiparkinsonian agents on the effects of narcoanalgesic drugs in the rat

Zusammenfassung Nachweis, dass die zentral wirksamen, anticholinergischen Agentien (Antiparkinson-Substanzen: Methyxen, Biperiden, Ethaproperazin, Caramiphen) sowohl die analgetischen Effekte von Morphin und Meperidin als auch ihre hemmende Wirkung auf konditionierte Reaktionen erhöhen.