Interaction of corticosterone and nicotine in regulation of prepulse inhibition in mice

The aim of the present Study was to investigate if different levels of circulating corticosterone (CORT) modulate the effect of nicotine on prepulse inhibition (PPI), a measure of sensorimotor gating that is disrupted in schizophrenia and other mental illnesses. Four groups of mice were investigated: sham-operated, adrenalectomized (ADX) and implanted with a cholesterol pellet, ADX and implanted with a 10 mg CORT pellet, or ADX and 50 mg, of CORT. Different CORT levels or doses of nicotine did not significantly affect startle responses. Baseline PPI was significantly reduced in mice implanted with the highest dose of CORT. In ADX mice implanted with cholesterol, nicotine treatment influenced PPI depending on the prepulse intensity. In ADX mice implanted with 50 mg of CORT, treatment with 10 mg/kg of nicotine caused a significant increase in PPI at all prepulse intensities. Binding studies showed that corticosterone treatment had significantly affected nicotinic acetylcholine receptor (nAChR) density in the mouse brain. Treatment with 50 mg CORT decreased I-125-epibatidine binding in the globus pallidus and I-125-alpha-bungarotoxin binding in the claustrum. These results suggest a possible interaction of corticosterone and nicotine at the level of the alpha4- and alpha7-type nAChR in the regulation of PPI. In situations of high circulating levels of corticosterone, nicotine may be beneficial to restore disruption of PPI. (C) 2004 Elsevier Ltd. All rights reserved.

Bibliometric analysis of nicotine research in China during the period of 1991 to 2007

With the widespread exposure of people to nicotine through recreational use of tobacco products, research into nicotine has attracted increasing attention. Tobacco smoking is by far the most important cause of lung cancer. As the world's largest producer and consumer of tobacco products, China bears a large proportion of the global burden of smoking-related disease; therefore, information on nicotine publications should be collected to formulate future research policy. In the present study, we investigated nicotine-related research articles published by Chinese authors that were indexed in the Science Citation Index (SCI) from 1991 to 2007. An indicator "citations per publication" (CPP) was used in the study to evaluate the impact of journals, articles, and institutes. The quantity of publications has increased at a quicker pace than the worldwide trend. Article visibility, measured as the frequency of being cited, also increased during the period. However, the overall quality of articles, based on the impact factor of journals publishing those articles, dropped behind the worldwide average level. There has been an increase in international collaboration, mainly with researchers in the USA. The average CPP of international co-authorship articles was higher than that of single country publications. Besides the USA, nicotine research in China will benefit from more collaboration with Taiwan, England, and Germany. Some 110 of 264 articles were published by a single institute, and the top six institutes were compared from various angles. Seventy-two subject categories were covered, and trends (in terms of both quantity and quality) of nicotine research in China were compared with worldwide trends. In addition, analysis of keywords in both nicotine and lung cancer research fields was applied to indicate research interests. Mutual cooperation among multiple disciplines needs further strengthening.

Molecularly imprinted solid-phase extraction sorbent for removal of nicotine from tobacco smoke

A sorbent showing specific affinity for nicotine was prepared by molecular imprinting technique, using nicotine as the template, methacrylic acid (MAA) as the functional monomer, ethyleneglycol dimethacrylate (EDMA) as the crosslinker and chloroform as the porogen. UV spectroscopic analysis in the molecular imprinting prepolymerization stage confirmed that nicotine could complex with the functional monomer by electrostatic interaction (ionic interaction and hydrogen bonding). The affinity and the binding properties of the imprinted polymer towards nicotine were investigated by equilibrium rebinding experiments. The results indicated the presence of nicotine-specific binding sites in the imprinted polymer, and that the imprinted polymer had a good capacity (90 mumol/g polymer) for nicotine. The elution conditions were optimized on the column packed with the imprinted polymer to elute nicotine quantitatively. The imprinted polymer was used as a solid-phase extraction (SPE) material for the removal of nicotine from tobacco smoke. The results obtained showed that the imprinted polymer was superior in terms of removing nicotine in tobacco smoke, compared with the commercial filter tip.

Comparative analysis of astaxanthin and its esters in the mutant E1 of Haematococcus pluvialis and other green algae by HPLC with a C30 column

A gradient reversed-phase high-performance liquid chromatography (HPLC) method using a C30 column was developed for the simultaneous determination of astaxanthin, astaxanthin monoesters and astaxanthin diesters in the green algae Chlorococcum sp., Chlorella zofingiensis, Haematococcus pluvialis and the mutant E1, which was obtained from the mutagenesis of H. pluvialis by exposure to UV-irradiation and ethyl methanesulphonate (EMS) with subsequent screening using nicotine. The results showed that the contents of total astaxanthins including free astaxanthin and astaxanthin esters ranged from 1.4 to 30.9 mg/g dry biomass in these green algae. The lower total astaxanthin levels (< 2 mg/g dry biomass) were detected in the green algae Chlorococcum sp. and C. zofingiensis. The higher total astaxanthin levels (> 16 mg/g dry biomass) were found in the green alga H. pluvialis and its mutant E1. It is notable that the mutant E1 is found to have considerably higher amounts of total astaxanthin (30.9 mg/g) as compared to the wild strain of H. pluvialis (16.1 mg/g). This indicates that UV-irradiation and EMS compound mutagenesis with subsequent screening using nicotine is an effective method for breeding of a high-producing astaxanthin strain of H. pluvialis. In addition, the green alga C. zofingiensis had a remarkably higher percentage of astaxanthin diesters (76.3% of total astaxanthins) and a remarkably lower percentage of astaxanthin monoesters (18.0% of total astaxanthins) in comparison with H. pluvialis (35.5% for diesters and 60.9% for monoesters), the mutant E1 (49.1% and 48.1%) and Chlorococcum sp. (18.0% and 58.6%).