The choroid plexuses are involved in CSF secretion and CSF K homeostasis. This study examines the potential role of K cotransport in these two processes using isolated rat lateral ventricle choroid plexuses. Bumetanide-sensitive 86Rb influx and efflux were measured to assess the response of K cotransport to changes in media osmolality and K concentration. Alterations in osmolality had no effect...

Insulin crosses the blood-brain barrier (BBB) via receptor-mediated transcytosis and has been suggested to augment uptake of peripheral substances across the BBB. The delta-opioid receptor-selective peptide D-penicillamine(2,5) (DPDPE), a Met-enkephalin analog, produces analgesia via a central nervous system-derived effect. In vitro (K(cell), microl. min(-1). mg(-1)) and in situ (K(in), microl....

For technical reasons, 86Rb is frequently preferred to 42K as a tracer for K+. Systematic comparisons of the two isotopes, however, are rarely done. In this paper we compare the transport of 42K and 86Rb in rat and mouse soleus muscle and in rat erythrocytes. Ouabain-suppressible K+ uptake in rat soleus was the same whether measured with 42K or 86Rb, both when stimulated by insulin, salbutamol ...

Amino acid accumulation within brush-border membrane vesicles (BBMV) from the larval midgut of Lepidoptera is driven by a K gradient. However, it can also be driven by a Na gradient, although with reduced efficiency. To examine the possibility that sodium and potassium ions are handled by the same amino acid transporter, glycine uptake into BBMV from Philosamia cynthia Drury was measured in the...

Potassium (K(+)) is the most important cationic nutrient for all living organisms and has roles in most aspects of plant physiology. To assess the impact of one of the main K(+) uptake components, the K(+) inward rectifying channel AKT1, we characterized both loss of function and overexpression of OsAKT1 in rice. In many conditions, AKT1 expression correlated with K(+) uptake and tissue K(+) le...

Radiocaesium (Cs) contamination of agricultural, semi-natural and natural areas is a worldwide problem that has arisen from human activities, such as intentional and unintentional discharges from the nuclear industry. The contamination of soils by Cs is of serious concern because of the long half-lives of the radionuclides (Cs = 2yr, Cs = 30yr) and the emission of harmful β and γ radiation duri...

Rice (Oryza sativa L.) requires adequate potassium (K) nutrition for optimal growth, grain yield, and disease resistance. Studies were conducted in 2001 and 2002 at the Pine Tree Branch Experiment Station (PTBS) to characterize K uptake by rice and investigate the effect of both K-fertilizer application rate and time on rice growth, K uptake, and grain yield. Potassium fertilizer was applied at...

plant growth promoting rhizobacteria (pgpr) has been identified as an alternative to chemical fertilizer to increase soil fertility and crop production in sustainable agriculture. the objective of this study was to investigate the effects of single and co-inoculation of azospirillum and pseudomonas strains on plant growth and nutrient uptake of maize as a factorial experiment. treatments includ...