Superfusion

The last three figures apparently refer to the ketone in the superfused condition. 

Isoeugenol, when cooled to a very low temperature, crystallises in fine needles, which melt at 34°, but it usually exists in a state of superfusion. 

Many oils possess the property of becoming solid at temperatures slightly below the ordinary, and a determination of the soliditying- or melting-points becomes an important criterion of purity in these cases. The melting-point is not usually the same as the solidifying-point, on account of the peculiar properties of bodies, included under the term superfusion, etc. In addition, the temperature recorded differs some-... 

This section examined small muscle preparations stimulated electrically or skinned muscle fibers maintained in superfused baths with different substance concentrations. The electrical stimulation was either continuous or intermittent for relatively short durations. 

Electrophysiological Experiments. Guinea pig myocardial cells prepared as described previously 24) were superfused at 37 C with a Tyrode solution. Electrical properties of the myocytes were examined by the patch-clamp methods (25) using fire-polished pipettes. The current was measured by means of a patch-clamp amplifier, stored on the tape through a digital PCM data recording system, and analyzed with a computer. 

Johnson, M.P. Hoffman, A.J. and Nichols, D.E. Effects of the enantiomers of MDA, MDMA and related analogs on [ H] serotonin and [ Hjdopamine release from superfused rat brain slices. Eur J Pharmacol 132 269-276, 1986. 

Figure 2 shows the concentration-dependent, MDMA-induced transmitter release from preloaded rat striatal slices superfused in vitro. From the figure, it is apparent that MDMA behaves similarly to the selective... 

FIGURE 2. Comparison of the MDMA-, PCA-, and methamphetamine-induced release of tritiated monoamines from superfused striatal slices in vitro... 

Figure 9 Graph of inhibition of acetylcholine release in superfused hippocampal slices versus CB1 receptor occupancy estimated from inhibition of [131I]AM281 binding.

Samuel, D., Lynch, M.A., and Littleton, J.M., Picrotoxin inhibits the effect of ethanol on the spontaneous efflux of [3H]-dopamine from superfused slices of rat corpus striatum, Neuropharmacology, 22, 1412, 1983. 

FIG. 5. Simultaneous and reproducible measurements of changes in SR and cytosolic Ca2+ in response to agonists. Pregnant rat myometrial cells were superfused with Krebs (2 mM Ca2+) and Carbachol (in Ca-free solution) applied as indicated. Repetitive applications of Carbachol evoked reproducible [Ca2+]j elevations (bottom trace) and SR [Ca2+]L decreases (upper traces). Left-hand axis cytosolic Ca2+. Right-hand axis intraluminal (SR) Ca2+changes, measured with mag-fluo-4. (Taken from Shmigol et al 2001.)... 

FIG. 5. Maintenance of the superficial buffer barrier depends on NCX-assisted Ca2+ transport from the SR lumen to the extracellular space. (A) Rate of loss of SR Ca2+ content, measured as a caffeine transient, into Ca2+ free perfusate at room temperature. (B) Rate of decline in [Ca2+ I from an elevated level, measured as fura 2 fluorescence ratio, into Ca2+ free superfusate, which is either Na+ free or contains 10 /rM CPA or is Na+ free and contains CPA. (C) This cartoon represents a model for maintained buffering by the superficial SR of Ca2+ entry. Ca2+ taken up by SERCA is subsequently released into the SR-PM junctional space from where it is extruded by the NCX. 

Regulation of InsP3 receptors by cytosolic Ca2+ lessons from superfusion experiments... 

Rapid superfusion of permeabilized hepatocytes loaded with 45Ca2+ has allowed us to examine the kinetics of InsP3-evoked Ca2+ mobilization with high temporal resolution under conditions where the concentrations of InsP3 and cytosolic Ca2+ can be rapidly changed (Marchant Taylor 1997). The results of these studies have... 

Taylor The experimental observation from which this comes is as follows. First, we pretreat the permeabilized cells in our superfusion apparatus with 100 /rM Ca2+ for about a second, to drive the cells to the state where they can no longer respond to InsP3 (even at heroic concentrations). Next, we wash out the Ca2+ to a low cytosolic level of 200 nM. Then we look for how long it takes for the normal response to a maximal concentration of InsP3 to recover. That takes a long time. 

Taylor In the experiments I showed we deliberately used a high Ca2+. This is partly a technical feature of the way that the superfusion works, but also we wanted to completely inhibit. The EC50 for this effect depends on how long the cells are left incubating in it, but it is in the order of 1.5 fiM. 

Fig. 5. Zn2+ enhances amphetamine induced release of [3H]MPP+. HEK-293 cells stably expressing the hDAT were preloaded with [3H]MPP+ and superfused upon reaching a stable baseline (basal efflux mean of the three fractions before drug addition hDAT wt (A) basal efflux 0.247 0.004% min T, i.e., 245.6 + 6.7 dpm min, n = 60 observations of randomly chosen experiments performed on different days hDAT-H193K (B) basal [3H]MPP+ efflux 0.433 0.08% min-1, i.e., 181.2 + 7.1 dpm min-1, n = 47. The experiment was started with the collection of 4-min fractions. After three fractions (12 min) of basal efflux, cells were exposed to Zn2+ (101iM), or left at control conditions as indicated. After six fractions (from 24 min and onward), amphetamine (10 pM) was added to all superfusion channels. After nine fractions (from 36 min and onward), all channels were switched back to control conditions. Data are presented as fractional efflux, i.e., each fraction is expressed as the percentage of radioactivity present in the cells at the beginning of that fraction. Symbols represent means + S.E. of 6-12 observations (one observation equals one superfusion chamber all experiments were performed in triplicate). Reproduced with permission from ref. (83).

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