Voltage-activated Ca(2+) channels and their role in the endocrine function of the pituitary gland in newborn and adult mice.
AuthorsSedej S, Tsujimoto T, Zorec R, Rupnik M
JournalJ Physiol
PubMed ID14724188
'We have prepared fresh pituitary gland slices from adult and, for the first time, from newborn mice to assess modulation of secretory activity via voltage-activated Ca(2+) channels (VACCs). Currents through VACCs and membrane capacitance have been measured with the whole-cell patch-clamp technique. Melanotrophs in newborns were significantly larger than in ... More
Blind spectral decomposition of single-cell fluorescence by parallel factor analysis.
AuthorsShirakawa H, Miyazaki S
JournalBiophys J
PubMed ID14990501
'Simultaneous measurement of multiple signaling molecules is essential to investigate their relations and interactions in living cells. Although a wide variety of fluorescent probes are currently available, the number of probes that can be applied simultaneously is often limited by the overlaps among their fluorescence spectra. We developed the experimental ... More
Structure of the inhibitory region of troponin by site directed spin labeling electron paramagnetic resonance.
AuthorsBrown LJ, Sale KL, Hills R, Rouviere C, Song L, Zhang X, Fajer PG
JournalProc Natl Acad Sci U S A
PubMed ID12239350
'Site-directed spin labeling EPR (SDSL-EPR) was used to determine the structure of the inhibitory region of TnI in the intact cardiac troponin ternary complex. Maeda and collaborators have modeled the inhibitory region of TnI (skeletal 96-112: the structural motif that communicates the Ca(2+) signal to actin) as a kinked alpha-helix ... More
New ratiometric fluorescent calcium indicators with moderately attenuated binding affinities.
AuthorsGee KR, Archer EA, Lapham LA, Leonard ME, Zhou ZL, Bingham J, Diwu Z
JournalBioorg Med Chem Lett
PubMed ID10915039
Mono-halogenated derivatives of the calcium indicators fura-2 and indo-1 were synthesized and their spectroscopic properties evaluated. Halogenation ortho or para to the bridging oxygen in the BAPTA nucleus had a more pronounced weakening effect on binding affinity than in the meta position in the fura derivatives. Two new excitation ratioable ... More
Pituitary control of BK potassium channel function and intrinsic firing properties of adrenal chromaffin cells.
AuthorsLovell PV, McCobb DP
JournalJ Neurosci
PubMed ID11331373
The discovery that the hypothalamic-pituitary-adrenocortical (HPA) endocrine stress axis controls an alternative splicing decision in chromaffin Slo-encoded BK (big potassium) channels raised the possibility that activation of the HPA could serve as a mechanism to tune the intrinsic electrical properties of epinephrine-secreting adrenal chromaffin cells. To test this, we compared ... More
Repetitive application of caffeine sensitizes caffeine-induced Ca2+ release in bullfrog sympathetic ganglion neurons.
AuthorsHigure Y, Nohmi M
JournalBrain Res
PubMed ID12393242
Cytosolic free calcium concentration ([Ca(2+)](i)) was recorded from cultured bullfrog sympathetic ganglion cells loaded with the Ca(2+)-indicator Fura-2 or Fura-6F. Repetitive application of caffeine at a low concentration, which either failed to produce any [Ca(2+)](i) elevation or induced a small gradual increase in [Ca(2+)](i) at first challenge, produced a drastic ... More
Sensitization of regulated exocytosis by protein kinase C.
AuthorsZhu H, Hille B, Xu T
JournalProc Natl Acad Sci U S A
PubMed ID12486252
Activation of protein kinase C (PKC) increases vesicular secretion in many cell types. We determined the calcium dependence of secretion and the size of the readily releasable pool of secretory granules in pituitary gonadotropes by photorelease of caged-calcium. The calcium affinity for exocytosis was roughly doubled by activation of PKC ... More
Cyclosporin A-insensitive permeability transition in brain mitochondria: inhibition by 2-aminoethoxydiphenyl borate.
AuthorsChinopoulos C, Starkov AA, Fiskum G
JournalJ Biol Chem
PubMed ID12750371
The mitochondrial permeability transition pore (PTP) may operate as a physiological Ca2+ release mechanism and also contribute to mitochondrial deenergization and release of proapoptotic proteins after pathological stress, e.g. ischemia/reperfusion. Brain mitochondria exhibit unique PTP characteristics, including relative resistance to inhibition by cyclosporin A. In this study, we report that ... More
Polycarboxylate fluorescent indicators as ion concentration probes in biological systems.
AuthorsKaterinopoulos HE, Foukaraki E
JournalCurr Med Chem
PubMed ID11860359
A large number of techniques have been applied to monitor the function of free metal ions in biological systems. Fluorescent ion probes have evolved into an extremely useful tool for contemporary experimentalists. Polycarboxylate indicators are widely used in the determination of metal ion concentrations, especially due to their cell membrane ... More
Characterization of a range of fura dyes with two-photon excitation.
AuthorsWokosin DL, Loughrey CM, Smith GL
JournalBiophys J
PubMed ID14990500
Two-photon excitation (TPE) spectra of Fura-2, -4F, -6F, -FF, and Furaptra were characterized using a tunable (750-850 nM) ultra-short pulse laser. Two-photon fluorescence of these dyes was studied in free solution and in the cytosol of isolated rabbit ventricular cardiomyocytes. The TPE spectra of the Ca(2+)-free and Ca(2+)-bound forms of ... More
Inositol 1,4,5-trisphosphate (IP3)-mediated Ca2+ release evoked by metabotropic agonists and backpropagating action potentials in hippocampal CA1 pyramidal neurons.
AuthorsNakamura T, Nakamura K, Lasser-Ross N, Barbara JG, Sandler VM, Ross WN
JournalJ Neurosci
PubMed ID11069943
We examined the properties of [Ca(2+)](i) changes that were evoked by backpropagating action potentials in pyramidal neurons in hippocampal slices from the rat. In the presence of the metabotropic glutamate receptor (mGluR) agonists t-ACPD, DHPG, or CHPG, spikes caused Ca(2+) waves that initiated in the proximal apical dendrites and spread ... More