We evaluated the effects of angiotensin II (ANG II) and its antagonists on prolactin release, intracellular calcium ([Ca2+]i) mobilization, and [3H]thymidine uptake in cells from normal rat pituitaries and from estrogen-induced pituitary tumors. ANG II (10(-7) to 10(-9) M) increased prolactin release significantly in control and not in tumoral cells. In control cells, ANG II (10(-6) to 10(-9) M...

In many neurons, subthreshold depolarization in the soma can transiently increase action-potential (AP)-evoked neurotransmission via analog-to-digital facilitation. The mechanisms underlying this form of short-term synaptic plasticity are unclear, in part, due to the relative inaccessibility of the axon to direct physiological interrogation. Using voltage imaging and patch-clamp recording from ...

Relay cells of the lateral geniculate nucleus, like those of other thalamic nuclei, manifest two distinct response modes, and these represent two very different forms of relay of information to cortex. When relatively hyperpolarized, these relay cells respond with a low threshold Ca2+ spike that triggers a brief burst of conventional action potentials. These cells switch to tonic mode when depo...

The roles of different K+ currents in regulating the generation and waveform of action potentials in Drosophila dorsal longitudinal flight muscles (DLMs) were examined in current-clamp experiments. In response to depolarizing current, DLMs displayed an initial transient rectification of the electronic potential lasting for up to hundreds of milliseconds. This delay in excitation was followed by...

Beractant, a natural surfactant, induces an antifibrogenic phenotype and apoptosis in normal human lung fibroblasts (NHLF). As intracellular Ca2+ signalling has been related to programmed cell death, we aimed to assess the effect of beractant on intracellular Ca2+ concentration ([Ca2+]i) in NHLF in vitro. Cultured NHLF were loaded with Fura-2 AM (3 μM) and Ca2+ signals were recorded by microflu...

We investigated the effect of various excitatory amino acids on intracellular free Ca2+ concentration ( [Ca2+]i) in single mouse hippocampal neurons in vitro by using the Ca2+-sensitive dye fura-2. In normal physiological solution, glutamate, kainate, N-methyl-D-aspartate, and quisqualate all produced increases in [Ca2+]i. When all extracellular Ca2+ was removed, kainate and N-methyl-D-aspartat...

The modification of the discharge pattern of subthalamic nucleus (STN) neurons from single-spike activity to mixed burst-firing mode is one of the characteristics of parkinsonism in rat and primates. However, the mechanism of this process is not yet understood. Intrinsic firing patterns of STN neurons were examined in rat brain slices with intracellular and patch-clamp techniques. Almost half o...

Calbindin is a fast Ca2+-binding protein expressed by Purkinje cells and involved in their firing regulation. Its deletion produced approximately 160-Hz oscillation sustained by synchronous, rhythmic Purkinje cells in the cerebellar cortex of mice. Parvalbumin is a slow-onset Ca2+-binding protein expressed in Purkinje cells and interneurons. In order to assess its function in Purkinje cell firi...

Oscillatory rises in intracellular Ca2+ concentration ([Ca2+]i) are the pivotal signal in the fertilization of mammalian eggs. The spatiotemporal dynamics of [Ca2+]i rises in mouse eggs subjected to intracytoplasmic sperm injection (ICSI) were analysed by Ca2+ imaging and compared with those subjected to in-vitro fertilization (IVF). The first Ca2+ transient occurred 15-30 min after ICSI in mos...

During the process of enhancing monocytic differentiation of the human leukemia line HL-60, 1,25-dihydroxyvitamin D3 (1,25(OH)2D3) also "primes" the cell for respiratory burst by increasing the uptake of Ca2+ across the plasma membrane (Hruska, K.A., Bar-Shavit, Z., Malone, J.D., and Teitelbaum, S.L. (1988) J. Biol. Chem. 263, 16039-16044). The present study asked if the maturational effect of ...