Exposure of neurons to a non-lethal hypoxic stress greatly reduces cell death during subsequent severe ischemia (hypoxic preconditioning, HPC). In organotypic cultures of rat hippocampus, we demonstrate that HPC requires inositol triphosphate (IP3) receptor-dependent Ca2+ release from the endoplasmic reticulum (ER) triggered by increased cytosolic NAD(P)H. Ca2+ chelation with intracellular BAPT...

Angiotensin II (100 nM) induced bi-phasic increases in cytosolic Ca2+ level ([Ca2+]i) through the activation of angiotensin II type 1 receptor. Pharmacological examinations using 10 µM verapamil, 30 µM La3+, and 1 µM thapsigargin indicated that the first phase of the [Ca2+]i-increase was mediated by Ca2+ release from sarcoplasmic reticulum (SR) and Ca2+ influx independently of voltage dependent...

Our objectives were to identify the relative contributions of [Ca2+]i and myofilament Ca2+ sensitivity in the pulmonary venous smooth muscle (PVSM) contractile response to the thromboxane A2 mimetic U-46619 and to assess the roles of PKC, tyrosine kinases (TK), and Rho-kinase (ROK) in that response. We tested the hypothesis that U-46619-induced contraction in PVSM is mediated by both increases ...

To examine the role of Ca2+ in early neuronal death, we studied the impact of free intracellular calcium concentration ([Ca2+]i) on survivability in populations of cultured mouse spinal neurons. We asked whether early neurotoxicity was triggered by Ca2+ influx, whether elevated [Ca2+]i was a predictive indicator of impending neuronal death, and whether factors other than [Ca2+]i increases influ...

A more complete understanding of calcium's role in cell division requires knowledge of the timing, magnitude, and duration of changes in cytoplasmic-free calcium, [Ca2+]i, associated with specific mitotic events. To define the temporal relationship of changes in [Ca2+]i to cellular and chromosomal movements, we have measured [Ca2+]i every 6-7 s in single-dividing Pt K2 cells using fura-2 and mi...

In Retzius neurones of the medicinal leech, Hirudo medicinalis, kainate activates ionotropic glutamate receptors classified as AMPA/kainate receptors. Activation of the AMPA/kainate receptor-coupled cation channels evokes a marked depolarization, intracellular acidification, and increases in the intracellular concentrations of Na+ ([Na+]i) and Ca2+. Qualitatively similar changes are observed up...

Kopper, Kara L., and Joseph S. Adorante. Regulation of intracellular calcium in N1E-115 neuroblastoma cells: the role of Na /Ca2 exchange. Am J Physiol Cell Physiol 282: C1000–C1008, 2002; 10.1152/ajpcell.00182.2001.—In fura 2-loaded N1E-115 cells, regulation of intracellular Ca2 concentration ([Ca2 ]i) following a Ca2 load induced by 1 M thapsigargin and 10 M carbonylcyanide p-trifluoromethyox...

Prolonged stimulation of cultured cerebellar neurons by kainic acid (KA) leads to death of neurons first evident from the swelling of soma and neurites. Stimulation is accompanied by increases in [Ca2+]i and [Na+]i as monitored using digital imaging microfluorimetry. "Blebs" tended to form on neurites with the highest increases in [Ca2+]i. Points of Ca2+ entry into neurites via glutamate-recept...

Propagation of action potentials in axons and dendrites increases intracellular Na+ ([Na+]i) and Ca2+ concentrations ([Ca2+]i). While the importance of [Ca2+]i in synaptic transmission is well established, a possible functional role of [Na+]i is unclear. In cultured hippocampal cells, [Na+]i was increased by veratridine. We have then measured spontaneous excitatory postsynaptic currents (sEPSCs...

In isolated rat hepatocytes, ATP and ADP (10(-6) M) rapidly mobilize intracellular Ca2+ and increase the concentration of free cytosolic Ca2+ ([Ca2+]i) within 1-2 s. The increase in [Ca2+]i is maximal (2.5- to 3-fold) by about 10 s and is dose-dependent, with ATP and ADP being half-maximally effective at 8 X 10(-7) and 3 X 10(-7) M, respectively. At submaximal concentrations, the rise in [Ca2+]...