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Discusses the intracellular regulatory mechanisms of 5-hydroxytryptamine (5-HT) release from enterochromaffin cells, in response to receptor stimulation. Role of autoreceptors on 5-HT release; Cholinergic mechanisms that stimulates 5-HT release; Influence of intracellular calcium ion on 5-HT release.

The ferret (Mustela putorius furo), a carnivore weighting 1–1.5 kg, is highly valued as a small animal model for determining the emetic activity of cytotoxic drugs. Because of its sensitivity to emetic stimuli, the ferret is now being used routinely for testing novel cytotoxic drugs and antiemetic agents. In our laboratory, ferrets were evaluated on their behavioral changes, pathological changes and pharmacological responses to cytotoxic drug-induced emesis. Cisplatin-induced emesis in ferrets was inhibited by 5-HT3 receptor antagonists in a dose dependent manner. 5-HT levels in the area postrema and in the ileum were increased by cytotoxic agents. Both abdominal vagotomy and ondansetron, a 5-HT3 receptor antagonist, remarkably inhibited cisplatin-induced emesis and cisplatin-induced increase in 5-HT levels in the area postrema. The cisplatin-induced increase of the ileal 5-HT levels, however, was not inhibited by vagotomy or ondansetron. Furthermore, compared with intraperitoneal administration, oral administration of ondansetron blocked cyclophosphamide-induced emesis more effectively and significantly. These results suggest that cytotoxic drugs induce emesis mainly through actions on the gastrointestinal tract. Cytotoxic drugs may cause 5-HT release from the enterochromaffin (EC) cells of the intestinal mucosa to stimulate 5-HT3 receptors on the afferent vagal fibers. Stimulation from the afferent vagal nerves appear to produce an increase in 5-HT levels in the area postrema. The increased 5-HT levels in the area postrema might trigger the emetic response induced by cytotoxic agents. In this review, we also discuss abdominal afferent vagus nerve activity and 5-HT release from EC cells using data from our laboratory. [ABSTRACT FROM AUTHOR]

Data driven precision agriculture aspects, particularly the dynamic disease management, require dynamic crop-weather-environment data at micro level. An experiment was conducted during four consecutive seasons (2009 Kharif, 2009-10 Rabi, 2010 Kharif and 2010-11 Rabi) in a semi-arid tropic region of India to understand the crop-weather-environment-disease relations using wireless sensory and field-level surveillance data on the groundnut crop for Leaf Spot (LS) disease, which is economically important yet more prone in the semi-arid tropic. Tailor-made various data mining techniques (Naïve Bayes classification with Gaussian distribution, rapid association rule mining and multivariate regression mining) were developed and applied to turn the data into useful information/knowledge/relations/trends and correlation to understand crop-weather-environment-disease continuum. These dynamics obtained from the data mining techniques and trained through proposed multivariate regression (MVR) mathematical models were validated with ground level surveillance data as well as ARI model (derived from ongoing long term weather-based experiment with diversely pooled data experimented from 10 seasons in semi-arid and arid zones). It was found that LS disease infection is strongly influenced by minimum temperature (18-20 °C), prolonged duration of leaf wetness (7-10 h), high humidity (75% or more) and age of the crop. These findings have been used for development of prediction models (One week and cumulative predictions), which can assist the user community to take respective ameliorative measures and it has been found that cumulative prediction model has performed better than ARI model with respect to ground level observations in all 16 diverse dates of sowing experiments spanning for two model-years. [ABSTRACT FROM AUTHOR]

The objective of this study was to compare two different rice simulation models-standalone (Decision Support System for Agrotechnology Transfer [DSSAT]) and web based (SImulation Model for RIce-Weather relations [SIMRIW])-with agrometeorological data and agronomic parameters for estimation of rice crop production in southern semi-arid tropics of India. Studies were carried out on the BPT5204 rice variety to evaluate two crop simulation models. Long-term experiments were conducted in a research farm of Acharya N G Ranga Agricultural University (ANGRAU), Hyderabad, India. Initially, the results were obtained using 4 years (1994-1997) of data with weather parameters from a local weather station to evaluate DSSAT simulated results with observed values. Linear regression models used for the purpose showed a close relationship between DSSAT and observed yield. Subsequently, yield comparisons were also carried out with SIMRIW and DSSAT, and validated with actual observed values. Realizing the correlation coefficient values of SIMRIW simulation values in acceptable limits, further rice experiments in monsoon (Kharif) and post-monsoon (Rabi) agricultural seasons (2009, 2010 and 2011) were carried out with a location-specific distributed sensor network system. These proximal systems help to simulate dry weight, leaf area index and potential yield by the Java based SIMRIW on a daily/weekly/monthly/seasonal basis. These dynamic parameters are useful to the farming community for necessary decision making in a ubiquitous manner. However, SIMRIW requires fine tuning for better results/decision making. [ABSTRACT FROM AUTHOR]

Abstract: With the advances in electronic and information technologies, various sensing systems have been developed for specialty crop production around the world. Accurate information concerning the spatial variability within fields is very important for precision farming of specialty crops. However, this variability is affected by a variety of factors, including crop yield, soil properties and nutrients, crop nutrients, crop canopy volume and biomass, water content, and pest conditions (disease, weeds, and insects). These factors can be measured using diverse types of sensors and instruments such as field-based electronic sensors, spectroradiometers, machine vision, airborne multispectral and hyperspectral remote sensing, satellite imagery, thermal imaging, RFID, and machine olfaction system, among others. Sensing techniques for crop biomass detection, weed detection, soil properties and nutrients are most advanced and can provide the data required for site specific management. On the other hand, sensing techniques for diseases detection and characterization, as well as crop water status, are based on more complex interaction between plant and sensor, making them more difficult to implement in the field scale and more complex to interpret. This paper presents a review of these sensing technologies and discusses how they are used for precision agriculture and crop management, especially for specialty crops. Some of the challenges and considerations on the use of these sensors and technologies for specialty crop production are also discussed. [ABSTRACT FROM AUTHOR]

Abstract: In neurons of dorsal motor nucleus of the vagus that is involved in the gastric motility and possibly emesis, application of 5-hydroxytryptamine produces membrane depolarization, and suppresses spike-repolarization and spike-afterhyperpolarization, suggesting divergent effects of 5-hydroxytryptamine through activating multiple subtypes of 5-hydroxytryptamine receptors. However, only the role of 5-hydroxytryptamine 2A receptors has been established to be responsible for the depolarization, and the mechanisms underlying the modulation of spikes remain unknown although a role of 5-hydroxytryptamine 4 receptors was implicated in modulations of spikes. There is now increasing evidence for the role of 5-hydroxytryptamine receptors in neurons involved in generating emesis following administration of anticancer drug. Since antagonists of 5-hydroxytryptamine 3/4 receptors are widely used as anti-emetic drugs, we have reevaluated the functional roles of 5-hydroxytryptamine 3/4 receptors of dorsal motor nucleus of the vagus neurons, especially in modulating transient outward currents that are presumed to be involved in spike-repolarization and spike-afterhyperpolarization. Whole-cell patch-clamp recordings were made from the dorsal motor nucleus of the vagus neurons, which were identified by a retrograde tracing method with dextran–tetramethylrhodamine–lysine injected into a bundle of abdominal vagus nerves. Under a voltage-clamp condition, dorsal motor nucleus of the vagus neurons expressed a prominent A-like current. The activation of 5-hydroxytryptamine 3 receptors reversibly increased the resting membrane conductance while the activation of 5-hydroxytryptamine 4 receptors led to an almost irreversible decrease in the A-like current. A long-lasting suppression of A-like current by transient activation of 5-hydroxytryptamine 4 receptors would result in a long-lasting increase in the excitability of dorsal motor nucleus of the vagus neurons, which might be involved in generation of the long-lasting facilitation of gastric motility or in generation of the long-lasting gastric relaxation through the activation of enteric non-adrenergic non-cholinergic neurons as implicated in the delayed emesis induced by anticancer drugs. [Copyright &y& Elsevier]

Patients with bulimia nervosa (BN) have disturbances of mood and behavior related to monoamine activities. There have been no reports concerning salivary concentrations of 5-hydroxytryptamine (5-HT) in patients with eating disorders such as anorexia nervosa (AN) and BN. In order to elucidate the involvement of 5-HT in eating disorders, 5-HT levels in the saliva of patients with BN were measured. Salivary 5-HT levels in patients with avoidant personality disorder (APD) were also measured as an active control. 5-HT levels in the saliva of patients with BN and APD were compared with those of 32 healthy volunteers. Simultaneously, salivary 3,4-dihydroxyphenylacetic acid (DOPAC) was measured using HPLC-ECD. 5-HT levels were 41.04 ± 14.41 in 11 patients with BN (10 women and 1 man, average age 19.6 years), 78.55 ± 45.55 in 5 patients with APD (3 women and 2 men, average age 19.2 years) and 8.91 ± 1.10 ng/ml in 32 healthy controls (25 women and 7 men, average age 21.7 years), respectively. This is the first report that salivary concentrations of 5-HT were significantly higher in BN (p < 0.05) and in APD than those in healthy controls. We found no significant differences among the salivary DOPAC levels in BN, APD and those of healthy controls. There were no significant differences in body mass index among the three groups. 5-HT concentrations in the saliva may be a useful marker of stress or eating disorders. [ABSTRACT FROM AUTHOR]

We previously reported that exogenously administered isatin, an endogenous monoamine oxidase (MAO) inhibitor, significantly increased acetylcholine (ACh) and dopamine (DA) levels in the rat striatum. Selegiline [(−)-deprenil] was developed as a MAO-B inhibitor more than 30 years ago and widely used in the treatment of Parkinson’s disease. Effects of isatin or selegiline were investigated in Japanese encephalitis virus (JEV)-induced post-encephalitic parkinsonism rats by a pole test for detecting motor activity and by the determination of biogenic amine levels. Motor activity of JEV-induced rats receiving isatin (100 mg/kg per day for 1 week, i.p.) or selegiline (0.2 mg/kg per day for 1 week, i.p.) was significantly improved compared with that of untreated JEV-infected rats. Both isatin and selegiline prevented the decrease in striatal DA levels in JEV-rats. The increased turnover of DA (DOPAC/DA) induced by JEV was significantly inhibited by isatin, but not by selegiline. These results suggested that exogenously administered isatin and selegiline can improve JEV-induced parkinsonism by increasing DA concentrations in the striatum. [Copyright &y& Elsevier]

Determines the levels of acetylcholine (ACh), choline and dopamine (DA) in rat brain tissues after isatin administration to elucidate the role of isatin in regulating ACh levels. Description of isatin; ACh and DA concentrations in various brain regions before isatin administration to Wistar Kyoto rats; Effects of isatin microdialysis on ACh release from rat striatum.