Search results for "Nicotine"

Effects of Neuromuscular Blocking Agents on Neuronal Nicotine Receptors of Motor Nerves: Blockade of Nicotinic Autofacilitation and Backfiring

1991

ABSTRACT Tubocurarine reduced (60%) [3H]acetylcholine release from the isolated rat phrenic nerve at concentrations of 1 or 10 μM, but blocked backfiring of the phrenic nerve occuring after partial blockade of cholinesterase already at a concentration of 100 nM. The distinct potency of tubocurarine suggests differences between the presynaptic nicotine receptors mediating autofacilitation of release and preterminal nicotine receptors mediating backfiring of the motor nerve or a low agonist concentration at the latter receptors. The new neuromuscular blocking agents atracurium, pancuronium and vecuronium less effectively reduced [3H]acetylcholine release than tubocurarine indicating a lower a…

Flow injection Fourier transform infrared determination of nicotine in tobacco

2000

A fully automated procedure is proposed for the Fourier transform infrared (FTIR) determination of nicotine in tobacco. The method is based on the on-line extraction of nicotine with CHCl3. Samples, weighed inside empty extraction cartridges, were humidified with NH3 and the cartridges were installed in a flow manifold in which they were extracted with 2 ml CHCl3 for 2 min, then 400 microliters of the extract were introduced into a micro-flow cell using a carrier of CHCl3 and the IR spectrum was registered continuously. The absorbance, in the wavenumber range 1334-1300 cm-1, was measured, obtaining a peak as a function of time. The area of this peak was interpolated on a calibration line es…

Influence of E-smoking liquids on human periodontal ligament fibroblasts.

2014

Introduction: Over the last years, electronic cigarettes (ECs) have become more popular, particularly in individuals who want to give up smoking tobacco. The aim of the present study was to assess the influence of the different e-smoking liquids on the viability and proliferation of human periodontal ligament fibroblasts. Method and materials: For this study six test solutions with components from ECs were selected: lime-, hazelnut- and menthol-flavored liquids, nicotine, propylene glycol, and PBS as control group. The fibroblasts were incubated up to 96 h with the different liquids, and cell viability was measured by using the PrestoBlue® reagent, the ATP detection and the migration assay.…

Analysis of Nicotine and Its Oxidation Products in Nicotine Chewing Gum by a Molecularly Imprinted Solid-Phase Extraction

2000

Chromatographic stationary phases showing exceptional selectivity for nicotine can be prepared by the technique of molecular imprinting. Such phases were used in the search for a rapid cleanup step for nicotine and some of its oxidation products in chewing gum formulations. Thus, using an organic mobile phase, the nicotine analytes from chewing gums dissolved in nonpolar solvent were retained, whereas the nonpolar matrix eluted close to the void peak. A subsequent switch to an acidic mobile phase resulted in elution of the analytes as one sharp peak. Due to weak binding of the less basic oxidation products, other imprinted polymers were tested, and the solid-phase extraction procedure was o…

Sensitivity of neuronal nicotinic acetylcholine receptors to the opiate antagonists naltrexone and naloxone: receptor blockade and up-regulation

2003

In HEK293 cells stably expressing alpha4beta2 nAChRs, naltrexone, but not naloxone, blocked alpha4beta2 nAChRs via an open-channel blocking mechanism. In primary hippocampal cultures, naltrexone inhibited alpha7 nAChRs up-regulated by nicotine, and in organotypic hippocampal cultures naltrexone caused a time-dependent up-regulation of functional alpha7 nAChRs that was detected after removal of the drug. These results indicate that naltrexone could be used as a smoking cessation aid.

Time estimation in minimally abstinent smokers

1998

Computational Study on the Gas-Phase and Aqueous Solution Acidity of Nicotine

2017

Dielectric continuum solvation models (1), recently introduced in the routine of computational chemistry, have allowed organic chemists to afford solvation free energies, thus getting a closer insight on the real thermodynamics of chemical reactions in solution. Hydron transfer reactions are by far the most studied due to their importance both in physico-chemical systems and in synthetic applications. Since, on the other hand, molecules have almost always a notable molecular flexibility, each computational assessment should certainly address an accurate conformational analysis of each species involved in the chemical equilibrium. This rather annoying and troublesome complication has been au…

Enriched Environments for Rodents and their Interaction with Nicotine Administration

2012

An active lifestyle throughout the life cycle seems to delay cognitive aging and dementia and has also been evaluated as an intervention against addiction to cocaine and other drugs of abuse. In epidemiological studies with humans, it has proved difficult to separate the cognitive, social and physical components from other variables that influence lifestyle. Studies in animal models are useful for evaluating the impact of each of these factors and for uncovering the underlying mechanisms of the benefits of complex environments. Preclinical studies have employed the Environmental Enrichment paradigm (EE) which has been proposed as a preclinical model of positive life experiences in humans. E…

Individual Differences in Novelty-Seeking and Behavioral Responses to Nicotine: A Review of Animal Studies

2010

Individual differences in the behavioral responses to a novel environment have been proposed as a research tool to predict responsiveness to other behavioral tasks, response to certain events and individual vulnerability to nicotine addiction. In rats and mice, novelty seeking (defined as enhanced specific exploration of novel situations) is a complex behavior confirmed by a large body of neurochemical, endocrinological and behavioral data. We review the main standardized procedures employed to measure the novelty seeking trait in rodents and the ontogeny of this behavior throughout the life-span taking into account that novelty seeking can be permanently modified as a consequence of partic…

Treatment with Nicotine derived Nitrosamine Ketone NNK Causes Disruption of Blood Brain Barrier BBB and Microglia Activation in Mice

2022

4-Methylnitrosamino-1-(3-pyridyl)-1-butanone (NNK) is a nicotine metabolite produced within the tobacco plant, from combustion, and from metabolic breakdown. Cigarette Smoke (CS) continues to be a leading cause for decline of quality of life as well as deaths globally. While the link to poor health and eventually early death has been accepted for decades, it is increasingly recognized that smoking may contribute to a broad range of disorders. Epidemiologically, CS has been associated with neuroinflammation and several neurological disorders including Alzheimer’s disease, stroke, and multiple sclerosis. While direct links are not fully understood, studies in a humanized flow-based in vitro b…