. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. — os. soma 2 uM TPGN Treatments TPGN * ZOO uM Pb Figure 1. Effects of lend and pharmacological agents an ilic cal- cium fln.\ observed in AplyMa bag cell neurons. .4. Increasing Pb'2 (Phi concentrations stimulated a corresponding increase in Ca ctllu\ signals. B. Ca*: channel Mucker verapamil (VPMLl markedly reduced the Pb':-indiiced Ca'} efflux while Co*" (Co) slight/v diminished the signals. C. Thapsigargin (TPGN), a Ca*~-ATPase inhibitor, generates a sustained increase in cffln.\, a level mil significantly altered b\
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. — os. soma 2 uM TPGN Treatments TPGN * ZOO uM Pb Figure 1. Effects of lend and pharmacological agents an ilic cal- cium fln.\ observed in AplyMa bag cell neurons. .4. Increasing Pb'2 (Phi concentrations stimulated a corresponding increase in Ca ctllu\ signals. B. Ca*: channel Mucker verapamil (VPMLl markedly reduced the Pb':-indiiced Ca'} efflux while Co*" (Co) slight/v diminished the signals. C. Thapsigargin (TPGN), a Ca*~-ATPase inhibitor, generates a sustained increase in cffln.\, a level mil significantly altered b\ the subsequent addition of Pb'-'. Background (bgl measurements or nega- live controls were done at 60-200 urn awa\ from the plasmamembrane, while positive controls (.soma) were measured at the nenronal membrane before mis of the treatments were added. To record the transmembrane Ca*2 signals, a CaH ^selective self-referencing probe was used. This instrument and method of operation have been described in detail (8, II. 12); the probe takes advantage of the inherent, albeit low voltage signals caused by the movement of ions across cell membranes. Silanized microelec- trodes tipped with a 3()-/jm column of Ca* ^selective liquid mem- brane (Fluka Calcium lonophore 1. Cocktail A) were moved alter- nately at Hz, orthogonal to the plasma membrane, between a near pole within 1 pm of the surface and a distant point 10 pm away. The circuit was completed with a 3 M KC1 bridge electrode. Calcium flux was calculated with the Pick equation using the differential voltage recorded between the two extremes of oscilla- tion (12). Background measurements were made at points further than 60 fjm from the cell membrane. This whole set-up was mounted on a Zeiss IM 35 inverted microscope, in a Faraday cage, on an air table. Addition of lead acetate in 50-pM increments (50-300/jM concentrations) to the bathing medium caused a dose-dependent increase in Ca*2 efflux signals (Fig. 1A) and demonstra
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
