Lipid bilayer experiments were performed in the presence of hemolysin of Escherichia coli. The toxin had a rather low activity in membranes formed of pure lipids, such as phosphatidylcholine or phosphatidylserine. In membranes from asolectin, a crude lipid mixture from soybean, hemolysin was able to increase the conductance by many orders of magnitude in a steep concentration-dependent fashion,...

Cystic Fibrosis (CF) is the most common lethal monogenic disorder in Caucasians, estimated to affect one per 2500-4000 newborns. CF is caused by mutations in the gene encoding the CF transmembrane conductance regulator (CFTR) [1, 2]. CFTR acts mainly as a chloride channel and has other regulatory roles, including inhibition of sodium transport through the epithelial sodium channel, regulation o...

Diazepam and (--)-pentobarbital each potentiate the increase in chloride ion conductance produced by gamma-aminobutyric acid (GABA) i voltage-clamped mouse spinal neurons grown in culture. Fluctuation analysis was used to compare the properties of elementary ion-channel events underlying the chloride conductance produced by GABA alone and during potentiation by the two drugs. Neither drug alter...

Recombinant beta-toxin from Clostridium perfringens type C was found to increase the conductance of bilayer lipid membranes (BLMs) by inducing channel activity. The channels exhibited a distribution of conductances within the range of 10 to 380 pS, with the majority of the channels falling into two categories of conductance at 110 and 60 pS. The radii of beta-toxin pores found for the conductan...

Muscarinic cholinergic receptor stimulation evokes catecholamine secretion from some cell types, but the mechanism has not been well characterized. Using pheochromocytoma (PC12) cells, we show that the muscarinic agonist methacholine stimulates 45Ca2+ influx and [3H]norepinephrine release in a dose-dependent manner. Experiments performed in Na+-free medium or with inhibitors of voltage-dependen...

Low-conductance chloride channel from skeletal muscle SR vesicles of the crayfish Astacus fluviatilis was incorporated into planar lipid bilayers and its basic characteristics were investigated. The channel has a relatively low unitary conductance of 26 pS in symmetrical 160 mmol/l choline-chloride. The dependence of the channel conductance on Cl- concentration shows saturating behavior with a ...