A 1H-NMR investigation of the effects of ethanol and general anaesthetics on ion channels and membrane fusion using unilamellar phospholipid membranes

The influence of polyhydroxylated compounds on a hydrated phospholipid bilayer: a molecular dynamics study

“…Since biomembranes are the first component of the cell to interact with any external solute, the presence of cosolutes (CSL) or cosolvents (both further collectively referred to as CSLs for simplicity) at sufficiently high concentrations in the extracellular (and possibly also intracellular) medium may alter their physicochemical properties. This may in turn affect the functioning of intrinsic membrane proteins such as ion and water channels [3,4], or the resistance of the cell to potentially damaging conditions [5 -7]. For this reason, the modulation of membrane properties by CSLs, and in particular by small mono-and polyhydroxylated compounds (both further collectively referred to as polyhydroxylated compounds for simplicity), is involved in several processes of high biological, technological and medicinal relevance.…”

Application of (1)H and (31)P NMR to topological description of a model of biological membrane fusion: topological description of a model of biological membrane fusion.

“…3(1)). During fusion, the Pr 3+ ions get captured inside the vesicles and the splitting decreases (following spectra) (Kuczera et al, 1997;Hunt & Jones, 1983;Timoszyk & Janas, 2003). A similar relation was observed for the 31 P-NMR spectra of SUVs, showing two distinct signals assigned to PE/PS and PC (Fig.…”

“…During the study, 1 H-NMR and 31 P-NMR spectra for small unilamellar vesicles (SUV), which were dependent on time (concentration of Pr 3+ ions was constant), were also recorded. The presence of the paramagnetic Pr 3+ ions permits observation of separate signals from the hydrophilic part of the inner and outer lipid bilayers because of the changes in the chemical shift of the signals (Hunt & Tipping, 1978;Hunt & Jawaharlal, 1980;Hunt & Jones, 1983). The praseodymium ions form unstable associates with oxygen atoms in the phosphate group and increase their coordination number (Jones & Hunt, 1985;Kaszuba & Hunt, 1990;Gabrielska & Gruszecki, 1996).…”

“…The process of obtaining separate signals from the outer and the inner layers on the NMR spectrum, with the use of paramagnetic ions, is called splitting (Kaszuba & Hunt, 1990;Jeżowska et al, 1994;Gabrielska & Gruszecki, 1996;Kuczera et al, 1997). The idea of splitting, defined as the distance between the signals assigned to the choline or phosphate groups from the inner and the outer layers of the vesicle membrane, and the ratio of intensity of these signals have been used earlier by Hunt and co-workers (Hunt & Tipping,1978;Hunt & Jones, 1983;Jones & Hunt, 1985).…”

The effects of inhalation anesthetics on calcium-stimulated exocytosis in a natural membrane model system

“…fusion~of artificial lipid vesicles with one another (Simmonds and Halsey, 1986). While experiments with artificial lipid membranes have provided a wealth of information regarding the effects of anesthetic agents on lipid fluidity (Ueda et al, 1986;Hunt and Jones, 1983), molecular ordering (Firestone and Kitz, 1986), and thermotropism (Dluzewski et al, 1983), studies on intact cells have simply focused on the action of volatile anesthetics on the release of secretory products. By examining the effects of volatile anesthetics on an in vitro model system of natural membranes, we have attempted to provide new information about the effects of anesthetics on fundamental membrane fusion events and to reconcile apparent differences in the experimental results of previous studies.…”