Jennifer M. Ritchie

Learn More
1. Voltage-clamp studies were carried out on single rabbit myelinated nerve fibres at 14 degrees C with the method of Dodge & Frankenhaeuser (1958). 2. A method was developed to allow the ionic currents through the modal membrane to be calibrated exactly under voltage-clamp conditions by measuring the resistance of the internode through which the current(More)
The membrane of the myelinated axon expresses a rich repertoire of physiologically active molecules: (1) Voltage-sensitive NA+ channels are clustered at high density (approximately 1,000/microns 2) in the nodal axon membrane and are present at lower density (< 25/microns 2) in the internodal axon membrane under the myelin. Na+ channels are also present(More)
Many bacterial pathogens rely on a conserved membrane histidine sensor kinase, QseC, to respond to host adrenergic signaling molecules and bacterial signals in order to promote the expression of virulence factors. Using a high-throughput screen, we identified a small molecule, LED209, that inhibits the binding of signals to QseC, preventing its(More)
Patch-clamp recording from the plasmalemma of rat cultured astrocytes reveals the presence of both voltage-dependent sodium and voltage-dependent potassium conductances. These conductances are similar but not identical to the corresponding conductances in the axolemma. Whereas the h infinity relation of the sodium channels has the same voltage dependence as(More)
The mammalian gastrointestinal tract provides a complex and competitive environment for the microbiota. Successful colonization by pathogens requires scavenging nutrients, sensing chemical signals, competing with the resident bacteria and precisely regulating the expression of virulence genes. The gastrointestinal pathogen enterohaemorrhagic Escherichia(More)
The density of sodium channels in mammalian myelinated fibers has been estimated from measurements of the binding of [3H]saxitoxin to rabbit sciatic nerve. Binding both to intact and to homogenized nerve consists of a linear, nonspecific, component and a saturable component that represents binding to the sodium channel. The maximum saturable binding(More)
Horakova et al. were the first to observe that the phase of late outward current carried by potassium ions in frog and squid nerve is virtually absent in voltage-clamped rat nodes of Ranvier. This observation has been recently confirmed by Chiu et al. in rabbit nodes of Ranvier, suggesting that the nodal membrane in the mammal generally has few if any(More)
Enterohemorrhagic Escherichia coli (EHEC) is a group of food-borne pathogens that can cause diarrhea, colitis, and the hemolytic uremic syndrome (HUS). The importance of several of the proposed EHEC virulence factors lacks experimental verification in animal models. The limitations of current animal models led us to reexamine the infant rabbit model for the(More)
The functional organization of the mammalian myelinated nerve fiber is complex and elegant. In contrast to nonmyelinated axons, whose membranes have a relatively uniform structure, the mammalian myelinated axon exhibits a high degree of regional specialization that extends to the location of voltage-dependent ion channels within the axon membrane. Sodium(More)