The magnitude of cellular and shunt conductance of Necturus gastric antral mucosa was studied by (a) comparing the cellular PD response to transepithelial PD response during changes of ionic activity in the serosal bathing solution and (b) by measurement of current spread within the epithelial sheet. Using constant product KCl changes cellular resistance was 6,788 omegacm2 and shunt resistance ...

The thalamus is a major relay and integration station in the central nervous system. While there is a large body of information on the firing and network properties of neurons contained within sensory thalamic nuclei, less is known about the neurons located in midline thalamic nuclei, which are thought to modulate arousal and homeostasis. One midline nucleus that has been implicated in mediatin...

Integration of dual-barrel membrane patch-ion channel probes (MP-ICPs) to scanning ion conductance microscopy (SICM) holds promise of providing a revolutionized approach of spatially resolved chemical sensing. A series of experiments are performed to further the understanding of the system and to answer some fundamental questions, in preparation for future developments of this approach. First, ...

Fundamental understanding of ionic transport at the nanoscale is essential for developing biosensors based on nanopore technology and new generation high-performance nanofiltration membranes for separation and purification applications. We study here ionic transport through single putatively neutral hydrophobic nanopores with high aspect ratio (of length L = 6 μm with diameters ranging from 1 t...

The deviation of specific electrical conductance (EC) from conservative mixing behavior is well-established in the scientific literature. This principle based on observation that, as salt concentration a water sample increases, mobility individual ions decreases, and thus their ability to conduct electricity decreases. Despite this fact, some commonly used models for salinity transport San Fran...

Interactions between excitatory and inhibitory synaptic inputs on dendrites determine the level of activity in neurons. Models based on the cable equation predict that silent shunting inhibition can strongly veto the effect of an excitatory input. The cable model assumes that ionic concentrations do not change during the electrical activity, which may not be a valid assumption, especially for s...

BACKGROUND Zinc has been shown to have beneficial effects in vitro on epithelial barrier function, and in vivo to reduce intestinal permeability in malnourished children with diarrhoea. AIMS To determine whether malnutrition alters intestinal paracellular permeability, and whether zinc prevents such alterations. METHODS Guinea pigs were fed a normal protein diet (NP group), a low protein di...

The electrophysiology of cardiac myocytes is tightly coupled to mechanics. One aspect of this is apparent in the effects of mechanical strain on cardiac action potential dynamics. These can be considered through adjustments to classic electrophysiological models. The standard FitzHugh Nagumo model is a reduced two-variable model from Hodgkin-Huxley that can reproduce basic mechanisms of action ...

We employ a Hodgkin-Huxley type model of basolateral ionic currents in bullfrog saccular hair cells to study the genesis of spontaneous voltage oscillations and their role in shaping the response of the hair cell to external mechanical stimuli. Consistent with recent experimental reports, we find that the spontaneous dynamics of the model can be categorized using conductance parameters of calci...

1. Pressure-sensitive mechanosensory (P) neurones of the leech Hirudo medicinalis produce two responses to serotonin (5-HT): activation of a Cl- conductance and of a non-selective monovalent cation conductance. The effects of channel blockers, the receptor pharmacology and the second-messenger dependence of these responses were studied in voltage-clamped P cells in culture. Antagonists were app...