Efflux and accumulation of amino nitrogen in relation to the volume of rat renal inner medullary cells exposed to media of variable osmolality

Sleep and neurological autoimmune diseases

Neurological autoimmune diseases are characterized by an inappropriate immune response that by mistake targets the nervous system. As a result, patients experiment a number of neurological manifestations that may include insomnia, excessive daytime sleepiness, cataplexy, central hypoventilation, and REM sleep behavior disorder. Polysomnographic evaluation may reveal disorganized sleep architecture involving both NREM and REM sleep, and REM sleep intrusions into wakefulness. The study of sleep disorders in the setting of autoimmune diseases (e.g., narcolepsy, anti-IgLON5 disease, paraneoplastic neurological syndromes) shows that an abnormal immune-mediated (humoral or cellular) response target the neuronal structures (e.g., brainstem, hypothalamus) and neurotransmitters systems (e.g., hypocretin) that regulate sleep resulting in sleep impairment. It is a window to examine the link between the autoimmune system and the sleep regulation at the molecular, cellular, and anatomic level.

Targeting of microbe-derived metabolites to improve human health: The next frontier for drug discovery

Recent advances in metabolomic and genome mining approaches have uncovered a poorly understood metabolome that originates solely or in part from bacterial enzyme sources. Whether living on exposed surfaces or within our intestinal tract, our microbial inhabitants produce a remarkably diverse set of natural products and small molecule metabolites that can impact human health and disease. Highlighted here, the gut microbe-derived metabolite trimethylamine N-oxide has been causally linked to the development of cardiovascular diseases. Recent studies reveal drugging this pathway can inhibit atherosclerosis development in mice. Building on this example, we discuss challenges and untapped potential of targeting bacterial enzymology for improvements in human health.

Sodium-dependent potassium (86Rb+) efflux moderates volume regulation by cells in rat renal inner medullary slices exposed to strongly hyperosmotic media

The possibility has been examined that Na(+)-dependent K(+)-conductive pathways, known to exist in certain excitable cell membranes and inhibitable by the drug R56865, may also be present in cells of rat renal inner medulla, and that their activation may explain aspects of volume regulation by these cells in tissue slices exposed to strongly hyperosmotic media, as reflected by the rate of efflux of preloaded 86Rb+ (a marker for K+) and steady-state cell volumes and K+ contents. Cells incubated in media of 2000 mosmol/kg (400 mM Na+, 1172 mM urea) shrink and lose K+ by comparison with those in 720 mosmol/kg (203 mM Na+, 266 mM urea). If 2-aminisobutyric acid (10 mM) is added there is partial restoration of cell volume due to inwardly directed Na(+)-amino acid cotransport, but 86Rb+ efflux is accelerated and cells fail to regain net K+. R56865 (5 microM) completely blocks the increase in efflux and causes marked increases in cell volume and K+ contents, but only in strongly hyperosmotic media and in the presence of both Na+ and amino acid. In mildly hyperosmotic media, or media of 2000 mosmol/kg from which Na+ or amino acid is omitted, R56865 is without effect on these variables.