Modification of multiple ion channel functions in vivo by pharmacological inhibition: observation by threshold tracking and modeling.

Maintenance of axonal excitability relies on complex balance by multiple ion currents, but its evaluation is limited by in vitro single channel neurophysiological study on overall behavior. We sought to evaluate behaviors of multiple ion currents by pharmacological blockade. The threshold tracking technique was used to measure multiple excitability indices on tail sensory nerve of normal male mice before and after administration of either BaCl or ivabradine.

Quantitative MRI volumetry, diffusivity, cerebrovascular flow, and cranial hydrodynamics during head-down tilt and hypercapnia: the SPACECOT study.

To improve the pathophysiological understanding of visual changes observed in astronauts, we aimed to use quantitative MRI to measure anatomic and physiological responses during a ground-based spaceflight analog (head-down tilt, HDT) combined with increased ambient carbon dioxide (CO). Six healthy, male subjects participated in the double-blinded, randomized crossover design study with two conditions: 26.5 h of -12° HDT with ambient air and with 0.

Impaired Axonal Na(+) Current by Hindlimb Unloading: Implication for Disuse Neuromuscular Atrophy.

This study aimed to characterize the excitability changes in peripheral motor axons caused by hindlimb unloading (HLU), which is a model of disuse neuromuscular atrophy. HLU was performed in normal 8-week-old male mice by fixing the proximal tail by a clip connected to the top of the animal's cage for 3 weeks. Axonal excitability studies were performed by stimulating the sciatic nerve at the ankle and recording the compound muscle action potential (CMAP) from the foot.

Age-dependent effects on sensory axonal excitability in normal mice.

Serial recordings were performed to measure sensory excitability in peripheral nerves and elucidate age-dependent changes in neuronal ion currents in the peripheral sensory nervous system. The threshold tracking technique was used to measure multiple excitability indices in the tail sensory nerves of five normal male mice at four time points (6, 10, 14, and 19 weeks of age). A separate group of four mice was also measured at 43 weeks and at 60 weeks of age.