In vitro 1H-NMR spectroscopic analysis of metabolites in fast- and slow-twitch muscles of young rats.

The lactate (LAC), creatine (CRN), taurine (TAU), anserine (ANS) and carnosine (CAR) content of the masseter muscles (MM), long extensor muscles of digits (EDL) and soleus muscles (SOL) of young rats were determined using in vitro 1H-NMR spectroscopy to assess the significance of CRN, TAU, ANS and CAR in these muscles. The muscles of Wistar rats at the ages of 6, 12 and 18 weeks were dissected after decapitation and used for the metabolite analyses. The LAC and CAR content of all muscle groups showed no age dependence.

Modulation of the Ca2+-activated large conductance K+ channel by intracellular pH in human renal proximal tubule cells.

The Ca2+-activated and voltage-sensitive large conductance K+ channel (BK channel) with a slope conductance of about 300 pS is present in the surface membrane of cultured human renal proximal tubule epithelial cells (RPTECs). In this study we examined the effects of cytoplasmic pH (pH(i)) on activity and gating kinetics of the BK channel by using the inside-out configuration of the patch-clamp technique. At a constant cytoplasmic Ca(2+) concentration ([Ca2+]i), membrane depolarization raised channel open probability (P(o)), and lowering pH(i) shifted the P(o)-membrane potential (V(m)) relationship to the positive voltage direction.

Protein kinase G activates inwardly rectifying K(+) channel in cultured human proximal tubule cells.

An ATP-regulated inwardly rectifying K(+) channel, whose activity is enhanced by PKA, is present in the plasma membrane of cultured human proximal tubule cells. In this study, we investigated the effects of PKG on this K(+) channel, using the patch-clamp technique. In cell-attached patches, bath application of a membrane-permeant cGMP analog, 8-bromoguanosine 3',5'-monophosphate (8-BrcGMP; 100 microM), stimulated channel activity, whereas application of a PKG-specific inhibitor, KT-5823 (1 microM), reduced the activity.

Inwardly rectifying and Ca2+-permeable AMPA-type glutamate receptor channels in rat neocortical neurons.

Inwardly rectifying and Ca2+-permeable AMPA-type glutamate receptor channels in rat neocortical neurons. J. Neurophysiol.

Distribution of neurones expressing inwardly rectifying and Ca(2+)-permeable AMPA receptors in rat hippocampal slices.

1. Current-voltage (I-V) relationships and Ca2+ permeability of receptor channels activated by bath application of kainate, a non-desensitizing agonist of alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptors, were examined in various types of neurones in hippocampal slices of 5- to 13-day-old rats by using the tight-seal patch clamp recording technique. 2.