Learn More
Considerable evidence supports a Ca(2+) dysregulation hypothesis of brain aging and Alzheimer's disease. However, it is still not known whether (1) intracellular [Ca(2+)](i) is altered in aged brain neurons during synaptically activated neuronal activity; (2) altered [Ca(2+)](i) is directly correlated with impaired neuronal plasticity; or (3) the previously(More)
Nonlinear capacitative current (charge movement) was compared to the Ca current (ICa) in single guinea pig ventricular myocytes. It was concluded that the charge movement seen with depolarizing test steps from -50 mV is dominated by L-type Ca channel gating current, because of the following observations. (a) Ca channel inactivation and the immobilization of(More)
1. Currents through Ca2+ channels of single guinea-pig ventricular myocytes were studied using patch electrodes for whole-cell recording. Currents through Na+ and K+ channels were suppressed by the application of drugs or the substitution of impermeant ions. 2. Inactivation of the Ca2+ current (ICa) was investigated using a two-pulse protocol. The amount of(More)
1. Non-linear capacitative current (charge movement) was studied in isolated guinea-pig and rat ventricular myocytes. Linear capacitance was subtracted using standard procedures. Most of the experiments were done with guinea-pig myocytes, while rat myocytes were used for comparison. 2. When a myocyte was held at -100 mV, depolarizing clamp steps produced a(More)
Previous work has shown that the genes encoding each alpha1-adrenoceptor subtype are coexpressed throughout the peripheral vascular system. We have evaluated subtype-selective antibodies as tools to determine the extent of protein expression in arteries. The alpha1A-, alpha1B-, and alpha1D-adrenoceptors were detected in the medial layer of the aorta,(More)
The aim of this study was to quantify the contribution of the Na(+)/H(+) exchanger (NHE) and the Na(+) channel to the rise in cytosolic Na(+) concentration ([Na(+)]) that is seen in anoxic guinea pig ventricular myocytes. [Na(+)] was measured with the use of microfluorometry and was found to rise to 44 mM after prolonged anoxia. This rise was partially(More)
Na-loading single frog atrial cells produce changes in membrane currents that are similar to the creep currents originally observed in Na-loaded cardiac Purkinje fibers. Exposure to the Na ionophore, monensin, was used to induce creep currents in isolated atrial cells. The sensitivity of myocardial creep currents to three compounds that have been shown to(More)
Effects of (-)-BAY K 8644 on Ca2+ channel function were studied in guinea pig ventricular myocytes. It was found that the compound has both voltage-dependent stimulatory and inhibitory effects on the Ca2+ current (ICa), in agreement with prior studies. The basis for these effects was studied by evaluating the effects of (-)-BAY K 8644 on the Ca2+ channel(More)
The effects of Bay K 8644 on the high-threshold calcium channel was investigated by means of the whole-cell patch-clamp technique in single guinea pig ventricular myocytes. The goal of the experiments was to characterize the inhibitory effects of Bay K 8644 on the calcium channel, and identify the factors that influence the inhibition. Bay K 8644 was found(More)