Opioid Peptides in the Rabbit Carotid Body: Identification and Evidence for Co-Utilization and Interactions with Dopamine

Abstract: The rabbit carotid body is a catecholaminergic organ that contains dopamine and norepinephrine in a proportion of nearly 5:1. Chronic (15 days) carotid sinus nerve denervation or superior cervical ganglionectomy did not modify the carotid body dopamine content (5–6 nmol/mg of protein, equivalent to 250 pmol per carotid body), but sympathectomy reduced by ～ 50% the norepinephrine content. The carotid body has also a very high content of opioid activity (250 equivalent pmol of Leu-enkephalin/mg of protein) as measured by a radioreceptor assay that detects preferentially δ-opioid activity. In the carotid body the degree of opioid posttranslational processing to low-molecular-weight peptides (mostly Leu- and Met-enkephalin) is nearly 80%. HPLC identification of opioid peptides revealed that the sequences of Met- and Leu-enkephalin were in a proportion of nearly 6:1, indicating that the main opioid precursor in the carotid body is proenkephalin A. Chronic denervations of the carotid body did not modify the levels or the degree of opioid precursor processing. Acute hypoxic exposure of the animals (8% 0₂ in N₂; 3 h) resulted in a parallel decrease of dopamine and opioid activity, without any change in the degree of opioid processing. Norepinephrine levels were not affected by hypoxia. These findings suggest corelease of dopamine and opioids during natural hypoxic stimulation. In agreement with the analytical data. [d -Ala², d -Leu⁵]enkephalin, but not [d -Ala²,N-Me-Phe⁴ Gly⁵-ol]-enkephalin, reduced the in vitro release of dopamine induced by low Po₂, a high external K⁺ concentration, and dinitrophenol. Naloxone augmented the release response elicited by low Po₂ stimulation. These findings indicate that the previously described inhibitory actions of opioids are mediated, at least in part, by receptors located in chemoreceptor cells. Additional targets for opioid peptides, e.g., sensory nerve endings or blood vessels, and additional actions of opioids on chemoreceptor cells, e.g., long-term trophic actions, are not excluded.     

Neither altered incubation temperature during fetal development nor preferred rearing temperature improves leg bone characteristics of broilers

The present study evaluated whether broiler femoral and tibiotarsal characteristics (as assessed at slaughter age) could be improved if birds were reared under their preferred temperature and whether continuous high or low incubation temperature during the fetal period improves bone characteristics of broilers reared under heat stress or thermal preference. Broiler breeder eggs were incubated from day 13 until hatching under cold (36 °C), control (37.5 °C), or hot (39 °C) temperatures. Under these conditions, the eggshell temperatures were 37.4 ± 0.1°C, 37.8 ± 0.15°C, and 38.8 ± 0.3°C, respectively. Then, broiler chicks were reared under control, preferred (determined previously in thermal preference test), or high temperatures. At day 42 of age, the broilers were weighed and euthanized, and femora and tibiotarsi collected to measure weight, length, diaphysis perimeter, breaking strength, maximum flexion, rigidity, ash, phosphorus, and calcium. Rearing under the preferred temperature did not affect broiler body weight or femoral and tibiotarsal characteristics (P > 0.05). In contrast, high rearing temperature, decreased the body weight, mineral contents of both bones, femoral breaking strength, and tibiotarsal rigidity (P < 0.05). Regarding incubation temperature effects, egg exposure to cold and hot temperatures during the fetal period minimized or avoided a few effects of high rearing temperature, such as those on femoral and tibiotarsal morphological characteristics, mineral composition, and mechanical properties at slaughter age (P < 0.05), but not all. In conclusion, rearing under the preferred broiler temperature did not improve the bone characteristics, and the negative effects of high rearing temperature on bone development were minimized but not completely prevented by high or low temperature incubation during the fetal period.     

Factors influencing smallholder orange farmers for compliance with GobalGAP standards

The inability of farmers to comply with global good agricultural practices (GlobalGAP) standards has led to food safety issues harmful to human health and sustainable agriculture. This study aimed to assess the extent of GlobalGAP compliance among orange farmers and investigate barriers associated with compliance. Data were collected with structured questionnaires from 238 orange farmers. The findings showed that the farmers’ rate of adherence to the GlobalGAP standards was moderate (mean 3.58). Using factor analysis, the following four groups were identified as key barriers to compliance: personal and economic barriers, awareness and information barriers, institutional-support barriers, and infrastructure barriers. Institutional support barriers were deemed most important by farmers in compliance decisions (mean 4.29), followed by personal and economic barriers (mean 3.89). Therefore, a focus on the barriers faced by smallholder farmers would be crucial to improve their adoption of food safety standards. This can enhance the quality of agricultural commodities, customers’ safety, and the livelihood of smallholder farmers.     

Efficacy of choline and DHA supplements or enriched environment exposure during early adult obesity in mitigating its adverse impact through aging in rats

IntroductionThe aim of this study was to assess the efficacy of choline and DHA or exposure to environmental enrichment in obese adult and aging rats on alterations in body mass index, serum lipid profile and arterial wall changes, despite stopping high fat diet consumption and interventions during adulthood.Methods21 day old male Sprague Dawley rats were assigned as Experiment-1 & 2 - PND rats were divided into 4 groups with interventions for 7 months (n = 8/group). NC– Normal control fed normal chow diet; OB- Obese group, fed high fat diet; OB + CHO + DHA- fed high fat diet and oral supplementation of choline, DHA. OB + EE- fed high fat diet along with exposure to enriched environment .Experiment-2 had similar groups and interventions as experiment 1 but for next 5 months were fed normal chow diet without any interventions. Body mass index was assessed and blood was analyzed for serum lipid profile. Common Carotid Artery (CCA) was processed for Haematoxylin and eosin, Verhoff Vangeison stains. Images of tissue sections were analyzed and quantified using image J and tissue quant software.ResultsIn experiment.1, mean body mass index (p < 0.001), serum lipid profile (p < 0.01), thickness of tunica intima (p < 0.05), tunica media (p < 0.01) and percentage of collagen fibers (p < 0.01) of CCA were significantly increased in OB compared to NC. These were significantly attenuated in OB + CHO + DHA and OB + EE compared to OB. In experiment.2, mean body mass index (p < 0.01), serum lipid profile (p < 0.05) and thickness of tunica media of CCA (p < 0.01) were significantly increased in OB compared to NC. In OB + CHO + DHA and OB + EE, significant attenuation was observed in mean body mass index and mean thickness of tunica media compared to same in OB.ConclusionAdult obesity has negative impact on body mass index, serum lipid profile and arterial wall structure that persists through aging. Supplementation of choline and DHA or exposure to enriched environment during obesity attenuates these negative impacts through aging.     

Strand receptors with central cell bodies in the proximal leg joints of orthopterous insects

In various orthopterous insects backfilling of leg nerve 3B regularly stained, in the thoracic ganglia, small cell bodies that resemble those of central sensory neurons reported in the locust (Br?unig and Hustert 1980). Centrifugal cobalt infusion of this nerve revealed the end organs of those neurons in the periphery. In all species investigated one strand receptor is associated with the trochantin, while two others are situated in the coxa. In addition to these sense organs, the coxa contains a multipolar stretch receptor which spans the coxotrochanteral joint. The absence of chordotonal organs is discussed with reference to earlier work in this field.     

Peripheral quantitative computed tomography of the lower leg in children and adolescents: bone densities,cross-sectional sizes and muscle distribution reference data

Objectives:Peripheral quantitative computed tomography is utilised in increasing numbers of paediatric studies, however, very little is known about the reference limits for pQCT tibia measurements. The purpose of this study was to establish country-specific reference data for bone densities, cross-sectional sizes, strength and regional muscle distribution measured by pQCT in children and adolescents.Methods:Stratec XCT 2000L apparatus was used. The measurement sites were 4%, 14%, 38% and 66% of the tibia length. The study group consisted of 222 participants (103 girls) aged 4,3-19,4 yrs. ANCOVA was used to assess the main determinants of pQCT outcomes. The LMS method was used to fit the percentile curves for each outcomes.Results:Weight and age were the main determinants for most of the pQCT outcomes. Smoothed percentile curves were developed by age and by height for both sexes.Conclusion:In this study we present reference data for bone densities, cross-sectional size and strength as well as for regional muscle distribution measured by pQCT at certain sites of the lower leg to allow simple calculation of reliable Z scores.     

Evaluation of RF electromagnetic field exposure levels from cellular base stations in Korea

This article presents the measurement results of human exposure to CDMA800 and CDMA1800 signals at locations in Korea where the general public has expressed concern. Measurements were performed at 50 locations across the country to compare the electromagnetic field levels with the general public exposure compliance limits. At each site, the distances between the nearest single or co‐located base station and measurement positions were within a range of approximately 32–422 m. The measured exposure levels were very low compared with the international standard and the Korean human protection notice. The highest field level was 1.5 V/m, which corresponds to 0.15% of the International Commission on Non‐Ionizing Radiation Protection (ICNIRP) guidelines for human exposure. Bioelectromagnetics 31:495–498, 2010. © 2010 Wiley‐Liss, Inc.