Nitrous Oxide: Mechanism of Its Antinociceptive Action

Nitrous oxide (N2O) is an anesthetic gas known to produce an analgesic effect at sub-anesthetic concentrations. This analgesic property of N2O can be clinically exploited in a broad range of conditions where pain relief is indicated. The mechanism of this analgesic effect was long thought to be nonspecific in nature, but a landmark study by Berkowitz and others in 1976 first implicated an opioid mechanism of action, possibly via N2O-stimulated neuronal release of endogenous opioid peptides to activate opioid receptors. N2O-induced release of opioid peptide has been demonstrated in both in vivo and in vitro preparations. Reversal of N2O-induced antinociception in animals by narcotic antagonists has been reported by a number of laboratories. Subsequent studies have utilized more selective opioid antagonists to identify the opioid receptor subtypes involved in the antinociceptive effect of N2O. Extensive pharmacological testing in the mouse abdominal constriction and rat hot plate paradigms have established that N2O-induced antinociception is mediated by κ-opioid receptors in the former and by µ- and -opioid receptors in the latter. Current studies focus on two recent developments. The poor responsiveness of the DBA/2J mouse strain to N2O has led to pharmacogenetic studies that hope to identify the underlying genetic basis for antinociceptive responsiveness to N2O. Other research suggests an involvement of nitric oxide (NO) in mediating the antinociceptive effects of N2O in both rats and mice

Preliminary system design study for a digital fly-by-wire flight control system for an F-8C aircraft

The design of a fly-by-wire control system having a mission failure probability of less than one millionth failures per flight hour is examined. Emphasis was placed on developing actuator configurations that would improve the system performance, and consideration of the practical aspects of sensor/computer and computer/actuator interface implementation. Five basic configurations were defined as appropriate candidates for the F-8C research aircraft. Options on the basic configurations were included to cover variations in flight sensors, redundancy levels, data transmission techniques, processor input/output methods, and servo actuator arrangements. The study results can be applied to fly by wire systems for transport aircraft in general and the space shuttle

Increased Metabolic Rate in X-linked Hypophosphatemic Mice

Hyp mice are a model for human X-linked hypophosphatemia, the most common form of vitamin D-resistant rickets. It has previously been observed that Hyp mice have a greater food consumption per gram body weight than do normal mice. This led to the search for some alteration in metabolism in Hyp mice. We found that oxygen consumption was significantly higher in Hyp mice than in normal C57BL/6J mice and this was accompanied by an increased percentage of cardiac output being delivered to organs of heat production (liver and skeletal muscle), to the skin, and to bone and a decreased percentage to the gastrointestinal tract of Hyp mice. The increased oxygen consumption in Hyp mice was not associated with increased plasma free T4 levels and was not affected by alterations in plasma phosphate produced by a low phosphate diet. The cause of the increased oxygen consumption is not known, and the role that this change and reported changes in distribution of cardiac output may play in the development of X-linked hypophosphatemia is also unknown. Study of the cardiovascular and thermoregulatory systems in Hyp mice should help increase understanding of the underlying mechanisms of this disease

India: Domestic Issues, Strategic Dynamics, and U.S. Relations

[Excerpt] President Barack Obama’s Administration has sought to build upon the deepened U.S. engagement with India begun by President Bill Clinton in 2000 and expanded upon during much of the past decade under President G.W. Bush. This “U.S.-India 3.0” diplomacy was most recently on display in July 2011, when the second U.S.-India Strategic Dialogue session saw a large delegation of senior U.S. officials visit New Delhi to discuss a broad range of global and bilateral issues. Many analysts view the U.S.-India relationship as being among the world’s most important in coming decades and see potentially large benefits to be accrued through engagement on many convergent interests. Bilateral initiatives are underway in all areas, although independent analysts in both countries worry that the partnership has lost momentum in recent years. Outstanding areas of bilateral friction include obstacles to bilateral trade and investment, including in the high-technology sector; outsourcing; the status of conflict in Afghanistan; climate change; and stalled efforts to initiate civil nuclear cooperation. India is the world’s most populous democracy and remains firmly committed to representative government and rule of law. Its left-leaning Congress Party-led ruling national coalition has been in power for more than seven years under the leadership of Prime Minister Manmohan Singh, an Oxford-trained economist. New Delhi’s engagement with regional and other states is extensive and reflects its rising geopolitical status. The national economy has been growing rapidly—India’s is projected to be the world’s third-largest economy in the foreseeable future—yet poor infrastructure, booming energy demand, and restrictive trade and investment practices are seen to hamper full economic potential. Despite the growth of a large urban middle-class, India’s remains a largely rural and agriculture-based society, and is home to some 500-600 million people living in poverty. This report will be updated periodically

Increased mRNA Expression for the α\u3csub\u3e1\u3c/sub\u3e Subunit of the GABA\u3csub\u3eA\u3c/sub\u3e Receptor Following Nitrous Oxide Exposure in Mice

The mechanisms by which nitrous oxide (N2O) produces physical dependence and withdrawal seizures are not well understood, but both N2O and ethanol exert some of their effects via the GABAA receptor and several lines of evidence indicate that withdrawal from N2O and ethanol may be produced through similar mechanisms. Expression levels of mRNA transcripts encoding several GABAA receptor subunits change with chronic ethanol exposure and, therefore, we hypothesized that N2O exposure would produce changes in mRNA expression for the α1 subunit. Male, Swiss–Webster mice, 10–12 weeks of age, were exposed for 48 h to either room air or a 75%:25% N2O:O2 environment. Brains were sectioned and mRNA for the a subunit was detected by in situ hybridization using an 35S-labelled cRNA probe. N2O exposure produced a significant increase in expression levels of the α1 subunit mRNA in the cingulate cortex, the CA1/2 region of the hippocampus, the dentate gyrus, the subiculum, the medial septum, and the ventral tegmental area. These results lend support to the hypothesis that N2O effects are produced, at least in part, through the GABAA receptor and that N2O produces these effects through actions in the cingulate cortex, hippocampus, ventral tegmental area and medial septum. These results are also further evidence that ethanol and N2O produce dependence and withdrawal through common mechanisms

CONJOINT ANALYSIS OF THE MID-ATLANTIC FOOD-FISH MARKET FOR FARM-RAISED HYBRID STRIPED BASS

Conjoint analysis was used to examine buyer preferences toward farm-raised hybrid striped bass at the wholesale, retail, and restaurant levels. Low price and round form were found to be important attributes in the product preference rating for the wholesale and retail markets. The filleted form contributed the most to restaurants' preference rating. Following these, larger fish size was preferred by all markets.Agribusiness,