Diclofenac
(active ingredient of Voltaren) has a significant, multifaceted
role in medicine, pharmacy, and biochemistry. Its physical properties
and impact on biomolecular structures still attract essential scientific interest. However, its interaction
with water has not been described yet at the molecular level. In the
present study, we shed light on the interaction between the steric
hindrance (the intramolecular N–H···O bond,
etc.) carboxylate group (−CO2–) with water. Aqueous solution of sodium declofenac is investigated
using attenuated total reflection-infrared (ATR-IR) and computational
approaches, i.e., classical molecular dynamics (MD) simulations and
density functional theory (DFT). Our coupled classical MD simulations,
DFT calculations, and ATR-IR spectroscopy results indicated that the
−CO2– group of the diclofenac
anion undergoes strong specific interactions with the water molecules.
The combined experimental and theoretical techniques provide significant
insights into the spectroscopic manifestation of these interactions
and the structure of the hydration shell of the −CO2– group. Moreover, the developed methodology for
the theoretical analysis of the ATR-IR spectrum could serve as a template
for the future IR/Raman studies of the strong interaction between
the steric hindrance −CO2– group
of bioactive molecules with the water molecules in dilute aqueous
solutions.
This paper presents the results of a laser interference microscopy study of the morphology and dynamical properties of myelinated nerve fibres. We describe the principles of operation of the phase-modulated laser interference microscope and show how this novel technique allows us to obtain information non-invasively about the internal structure of different regions of a nerve fibre. We also analyse the temporal variations in the internal optical properties in order to detect the rhythmic activity in the nerve fibre at different time scales and to shed light on the underlying biological processes. We observe pronounced frequencies in the dynamics of the optical properties and suggest that the oscillatory modes have similar origin in different regions, but different strengths and mutual modulation properties.
Raman, NMR and EPR spectroscopy and electrophysiology methods were used to investigate the excitability and the packaging of myelin lipid layers and its viscosity during nerve exposure to pronase E. It was established that during exposure of nerve to pronase E the action potential (AP) conduction velocity and the Schwann cell (SC) (or myelin) water ordering increases, but the nerve myelin refractive index and internode incisions numbers decrease. This effect included two periods–short- and long-time period, probably, because the first one depends on SC protein changes and the second one–on the nerve fiber internode demyelination. It was concluded that high electrical resistance of myelin, which is important for a series of AP conduction velocity, not only depends on nerve fiber diameter and the myelin lipid composition, but also on the regularity of myelin lipid fatty acids and myelin lipid layer packing during the axoglial interaction.
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