Pitfalls in the Detection of Volatiles Associated with Heated Tobacco and e-Vapor Products When Using PTR-TOF-MS.

We investigated the applicability of proton transfer reaction-time-of-flight mass spectrometry (PTR-TOF-MS) for quantitative analysis of mixtures comprising glycerin, acetol, glycidol, acetaldehyde, acetone, and propylene glycol. While PTR-TOF-MS offers real-time simultaneous determination, the method selectivity is limited when analyzing compounds with identical elemental compositions or when labile compounds present in the mixture produce fragments that generate overlapping ions with other matrix components. In this study, we observed significant fragmentation of glycerin, acetol, glycidol, and propylene glycol during protonation via hydronium ions (HO).

Tolperisone-type drugs inhibit spinal reflexes via blockade of voltage-gated sodium and calcium channels.

The spinal reflex depressant mechanism of tolperisone and some of its structural analogs with central muscle relaxant action was investigated. Tolperisone (50-400 microM), eperisone, lanperisone, inaperisone, and silperisone (25-200 microM) dose dependently depressed the ventral root potential of isolated hemisected spinal cord of 6-day-old rats. The local anesthetic lidocaine (100-800 microM) produced qualitatively similar depression of spinal functions in the hemicord preparation, whereas its blocking effect on afferent nerve conduction was clearly stronger.

Bicarbonate and thiocyanate ions affect the gating of gamma-aminobutyric acid(A) receptors in cultured rat cortical cells.

The ionophore function of gamma-aminobutyric acid(A) (GABA(A)) receptors was studied by whole-cell patch clamp electrophysiology in primary cultures of rat cerebral cortex. Chloride ions were replaced for SCN(-) (thiocyanate) and HCO(-3) (bicarbonate) ions. The EC(50) values of the GABA(A) agonist muscimol (HCO(-3)>Cl(-)>SCN(-)) varied parallel with the free energies of dehydration of the anions, while the inhibition constants of the GABA(A) antagonist bicuculline methiodide were not affected.