ABSTRACT
AIM: We determined the role of brain Gαi2 proteins in mediating the neural and humoral responses of conscious male Sprague-Dawley rats to acute peripheral sodium challenge. METHODS: Rats pre-treated (24-h) intracerebroventricularly with a targeted oligodeoxynucleotide (ODN) (25 µg per 5 µL) to downregulate brain Gαi2 protein expression or a scrambled (SCR) control ODN were challenged with an acute sodium load (intravenous bolus 3 m NaCl; 0.14 mL per 100 g), and cardiovascular parameters were monitored for 120 min. In additional groups, hypothalamic paraventricular nucleus (PVN) Fos immunoreactivity was examined at baseline, 40, and 100 min post-sodium challenge. RESULTS: In response to intravenous hypertonic saline (HS), no difference was observed in peak change in mean arterial pressure between groups. In SCR ODN pre-treated rats, arterial pressure returned to baseline by 100 min, while it remained elevated in Gαi2 ODN pre-treated rats (P < 0.05). No difference between groups was observed in sodium-evoked increases in Fos-positive magnocellular neurons or vasopressin release. V1a receptor antagonism failed to block the prolonged elevation of arterial pressure in Gαi2 ODN pre-treated rats. A significantly greater number of Fos-positive ventrolateral parvocellular, lateral parvocellular, and medial parvocellular neurons were observed in SCR vs. Gαi2 ODN pre-treated rats at 40 and 100 min post-HS challenge (P < 0.05). In SCR, but not Gαi2 ODN pre-treated rats, HS evoked suppression of plasma norepinephrine (P < 0.05). CONCLUSION: This highlights Gαi2 protein signal transduction as a novel central mechanism acting to differentially influence PVN parvocellular neuronal activation, sympathetic outflow, and arterial pressure in response to acute HS, independently of actions on magnocellular neurons and vasopressin release.
Subject(s)
Baroreflex/physiology , Blood Pressure/physiology , GTP-Binding Protein alpha Subunit, Gi2/metabolism , Neurons/physiology , Paraventricular Hypothalamic Nucleus/physiology , Animals , Autonomic Nervous System/physiology , Consciousness , Enzyme-Linked Immunosorbent Assay , Gene Knockdown Techniques , Immunohistochemistry , Male , Rats , Rats, Sprague-Dawley , Sodium/bloodABSTRACT
There is a need to calculate specific absorbed fractions (SAFs) in voxel phantoms for internal dosimetry. For this purpose, an EGS4 user code for calculating SAFs using voxel phantoms was developed on the basis of an existing EGS4 user code for external dosimetry (UCPIXEL). In the developed code, the transport of photons, electrons and positrons in voxel phantoms can be simulated, particularly the transport simulations of secondary electrons in voxel phantoms. The evaluated SAFs for the GSF 'Child' voxel phantom using the developed code were found to be in good agreement with the GSF evaluated data. In addition, SAFs in adult voxel phantoms developed at JAERI were evaluated using the developed code and were compared with several published data. It was found that SAFs for organ self-absorption depend on the organ masses and would be affected by differences in the structure of the human body.
Subject(s)
Models, Biological , Models, Statistical , Radioisotopes/analysis , Radioisotopes/pharmacokinetics , Whole-Body Counting/methods , Whole-Body Counting/standards , Absorption , Computer Simulation , Female , Humans , Japan , Male , Monte Carlo Method , Organ Specificity , Phantoms, Imaging , Radiation Dosage , Reproducibility of Results , Sensitivity and Specificity , Tomography, X-Ray Computed/methodsSubject(s)
Fresh Water/analysis , Hydrocarbons/analysis , Hydrocarbons/chemistry , Water Pollutants, Chemical/analysis , Benzopyrans/analysis , Chemistry Techniques, Analytical/methods , Chlorides/analysis , Chlorides/metabolism , Cold Temperature , Environmental Pollutants , Kinetics , Osmolar Concentration , Oxidation-Reduction , Phthalic Acids/analysis , Solubility , TemperatureABSTRACT
Oligonucleotides covalently linked to isoalloxazines via polymethylene linker were synthesized and characterized. The thymidine decamer having a primary aminoalkyl group at the 5'-end of internucleotide linkage was coupled with the activated ester of isoalloxazine in liquid-phase. The interaction of the flavin modified thymidine decamers with polydA was investigated by using spectrophotometric method.
Subject(s)
Flavins/chemistry , Oligodeoxyribonucleotides/chemical synthesis , Base Sequence , Molecular Sequence Data , Molecular Structure , Oligodeoxyribonucleotides/chemistryABSTRACT
It has been suggested that naturally occurring copper and zinc concentrations in deep seawater are toxic to marine organisms when the free ion forms are overabundant. The effects of micronutrients on the growth of gametophytes of the ecologically and commercially significant giant kelp (Macrocystis pyrifera) were studied in defined media. The results indicate that toxic copper and zinc ion concentrations as well as cobalt and manganese deficiencies may be among the factors controlling the growth of marine organisms in nature.
