..., and after myocytes were acutely warmed to 11°C, which is in the upper range of temperatures experienced by burbot in nature. Results on K + channels support our hypothesis as the relative density of K-channel conductances in the burbot heart are similar to those found for cold-acclimated cold-active fish...

... + current fully inactivated during a depolarisation to +30 mV with a time-constant of ∼9 ms, and the time constant of recovery from inactivation at –70 mV was 13.2 s. This long-lasting inactivation of the K + channel was the major factor in the augmentation of both action potentials and contractions...

... in the transepithelial resistance were also observed following the hypotonicity exposure. The electrogenic V te and I sc responses to hypotonicity resulted from the activation of different K + and anion conductive pathways on the apical and basolateral membranes of the epithelium: (a) iberiotoxin-sensitive K + channels...

... very high ammonia levels in its tissues; (5) get rid of ammonia as NH 3 gas and, probably, (6) possesses background K + channels that are impermeable to NH 4 + . The effects of extracellular ammonia on the contraction performance of the heart from this fish were found to be the same as in rainbow trout...

...Brett N. Scott; Ming-Jiun Yu; Lenora W. Lee; Klaus W. Beyenbach SUMMARY The mechanisms of K + entry from the hemolymph into principal cells of Malpighian tubules were investigated in the yellow fever mosquito, Aedes aegypti . The K + channel blocker Ba 2+ (5 mmol l –1 ) significantly decreased...

... + ] irreversibly decreased fluid secretion rates from 6.38±0.95 nl min -1 (mean ± S.E.M.) to 1.48±0.52 nl min -1 ( N =8). In the presence of 6 mmol l -1 Ba 2+ , a blocker of basal K + channels,fluid secretion rates reversibly decreased and the hyperpolarization of both V bl and V ap seen in 50 mmol l -1 and 140...

... by the reversible inhibition of I sc by Ba 2+ added to the mucosal Ringer. Analysis of the kinetics of Ba 2+ inhibition of I sc indicates that there might be more than one type of K + channel carrying the I sc . This hypothesis was supported by power spectra obtained with a serosa-to-mucosa K + gradient, which...

...Wolfgang Zeiske; Heiko Meyer; Helmut Wieczorek SUMMARY In lepidopteran larvae, three transport mechanisms are involved in the active and electrogenic K + secretion that occurs in the epithelial goblet cells of the midgut. These consist of (i) basolateral K + channels, allowing K + entry from...

... the principal findings with respect to cation secretion in lepidopteran caterpillar midgut goblet cells (K + ) and in brush-border cells of Malpighian tubules (K + , Na + ). © 1992 by Company of Biologists 1992 homeostasis salt excretion membrane pathways K + channel K + /H + antiport H...

...CHRISTOPHER A. LORETZ; CHARLES R. FOURTNER Using patch-clamp techniques, a Ca 2+ -dependent, voltage-gated K + channel [K(Ca) channel] was isolated from the basolateral membrane of NaCl-absorbing intestinal epithelial cells of the goby Gillichthys mirabilis . This K(Ca) channel had a high...

...B. A. Miller; P. N. R. Usherwood ABSTRACT K + channel activity in cultured locust myofibres was investigated using gigaohm patch-clamp techniques. After 2 months in vitro the myofibres had a mean resting potential of -39±7mV (±S.D., N =42). Five types of K + channel were identified at this time...

...Daisuke Yamamoto; Nobuyuki Suzuki ABSTRACT Permeability and gating properties of single, non-inactivating, K + channel currents in cultured Drosophila neurons were studied using the gigaohm-seal patch-clamp technique. The non-inactivating K + currents were activated by depolarizing the membrane...

...Dwight N. Crawford; William R. Harvey ABSTRACT Ba 2+ and Ca 2+ prevent and reverse the Btk δ -endotoxin inhibition of the short-circuit current in isolated lepidopteran midgut. These findings support the K + pump–leak steady-state model for midgut K + homeostasis and the K + channel mechanism of Bt...

...Wade J. Sigurdson; Catherine E. Morris; Borys L. Brezden; David R. Gardner ABSTRACT Heart ventricle cells of Lymnaea stagnalis contain a stretch-activated K + channel which exhibits two open states and three closed states. Over the range 0 to –25 mmHg (1 mmHg = 133·3 Pa), the probability...