The mechanism by which progesterone causes localized suppression of the immune response during pregnancy has remained elusive. Using human T lymphocytes and T cell lines, we show that progesterone, at concentrations found in the placenta, rapidly and reversibly blocks voltage-gated and calcium-activated K 1 channels (K V and K Ca , respectively), resulting in depolarization of the membrane pote...

Hoesch, Robert E., Daniel Weinreich, and Joseph P. Y. Kao. Localized IP3-evoked Ca 2 release activates a K current in primary vagal sensory neurons. J Neurophysiol 91: 2344–2352, 2004. First published December 10, 2003; 10.1152/jn.01008.2003. Electrophysiological and microfluorimetric techniques were used to determine whether intracellular photorelease of caged IP3, and the consequent release o...

During vertebrate locomotion, spinal neurons act as oscillators when initiated by glutamate release from descending systems. Activation of NMDA receptors initiates Ca²⁺-mediated intrinsic membrane potential oscillations in central pattern generator (CPG) neurons. NMDA receptor-dependent intrinsic oscillations require Ca²⁺-dependent K⁺ (K(Ca)2) channels for burst termination. However, the locati...

This article offers an explanation for the apparent lack of Na, K-ATPase activity in parietal cells although ouabain has been known to inhibit gastric acid secretion since 1962. The gastric H, K-ATPase (proton-pump) seems to be acting in altered states, thus behaving like a Na, K-ATPase (Na-pump) and/or Ca-ATPase (Ca-pump) depending on cellular needs.  This conclusion is based on the following ...

Potassium channels represent the dominant ion conductance of vascular smooth muscle cell membranes and play a major role in the regulation of membrane potential (18,19). Membrane potential, in turn, regulates the open state probability of voltage-gated Ca channels (18,19). Thus, as illustrated in Fig. 1, the closure of K channels and the loss of outward K current lead to depolarization, opening...