Bovine serum albumin selectively increases the low-voltage-activated calcium current of NG108-15 neuroblastoma × glioma cells

Schmitt, Hans‐Georg; Meves, H.

doi:10.1016/0006-8993(94)91482-6

Cited by 10 publications

(3 citation statements)

References 17 publications

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“…Serum albumin has also been reported to increase the low-voltage-activated calcium current. 27 The serum concentration of albumin was variable in our patients (Table 1). Also the effects of their sera on the Na+ current amplitude (Table 2) and on the position of the h, curve (Fig.…”

Section: Discussionmentioning

confidence: 95%

Cerebrospinal fluid and serum from patients with inflammatory polyradiculoneuropathy have opposite effects on sodium channels

et al. 1995

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The effects of cerebrospinal fluid (CSF) and serum from patients having Guillain-Barré syndrome (GBS) or chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) on voltage-dependent Na+ channels were compared. Bathing human myoballs in CSF substantially reduced their Na+ currents (by > 40% with 8 of 10 patients) elicited at 1 Hz under whole-cell recording conditions. This was because, at the resting potential, more Na+ channels were inactivated (left-shift of the h infinity curve). CSF from patients with other neurological diseases (OND) produces a similar, but smaller, effect. In contrast, serum samples from the same GBS and OND patients caused an increase of the Na+ currents by reducing the number of Na+ channels inactivated at the resting potential. This right-shift of the h infinity curve is in part explained by the effect of serum albumin. We confirm that the CSF of most GBS and CIDP patients contains factors inhibiting voltage-dependent Na+ currents. There is no indication that such factors are effective in the serum of these patients.

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Section: Discussionmentioning

confidence: 95%

Cerebrospinal fluid and serum from patients with inflammatory polyradiculoneuropathy have opposite effects on sodium channels

et al. 1995

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“…2B). BSA binds free AA in the bath, effectively decreasing the external concentration and maintaining a steep concentration gradient for AA to diffuse from the cell into the external solution (Spector, 1975;Schmitt & Meves, 1994). Taken together the results from these whole cell patch clamp experiments suggest that AA inhibits both whole cell L_ and N-type currents in neonatal SCG neurons.…”

Section: Arachidonic Acid Inhibits Whole Cell Ba¥ Currents In Neonatamentioning

confidence: 98%

Effects of arachidonic acid on unitary calcium currents in rat sympathetic neurons

Liu

Rittenhouse

2000

The Journal of Physiology

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We have characterized the actions of arachidonic acid (AA) on whole cell and unitary calcium (Ca2+) currents in rat neonatal superior cervical ganglion (SCG) neurons using barium (Ba2+) as the charge carrier. Whole cell currents were elicited by stepping the membrane potential from −90 mV to +10 mV. Arachidonic acid (5 μm) was introduced into the bath in the continued presence of 1 μm (+)‐202‐791, an L‐type Ca2+ channel agonist. Under these conditions, the peak current, comprised mainly of N‐type current, and a slow, (+)‐202‐791‐induced component of the tail current were inhibited by 67 ± 6 and 60 ± 10%, respectively, indicating that AA inhibits both N‐ and L‐type currents. At a test potential of +30 mV, AA (5 μm) decreased unitary L‐ and N‐type Ca2+ channel open probability (Po) in cell‐attached patches that contained a single channel. For both channels, the underlying causes of the decrease in Po were similar. Arachidonic acid caused an increase in the percentage of null sweeps and in the number of null sweeps that clustered together. In sweeps with activity, the average number of openings per sweep decreased, while first latency and mean closed time increased. Arachidonic acid had no significant effect on unitary current amplitude or mean open time. Our findings are the first description of the inhibition of unitary L‐ and N‐type Ca2+ channel activity by AA and are consistent with both channels spending more time in their null mode and with increased dwell time in one or more closed states.

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“…BSA carries a net negative charge at physiological pH, and its adsorption to the SR membrane could increase the local concentration of Ca 2+ , which is a potent physiological activator of the release channel and which interacts synergistically with both caffeine and ATP to stimulate Ca 2+ release. Changes in surface charge density have been previously proposed to account for the BSA-induced potentiation of Ca 2+ channel currents in neuroblastoma x glioma cells (9).…”

Section: +mentioning

confidence: 99%

Bovine serum albumin potentiates caffeine- or ATP-induced tension in human skinned skeletal muscle fibers

Ponte

Oliveira²,

Suarez‐Kurtz³

1997

Braz J Med Biol Res

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Human skinned muscle fibers were used to investigate the effects of bovine serum albumin (BSA) on the tension/pCa relationship and on the functional properties of the Ca 2+ -release channel of the sarcoplasmic reticulum (SR). In both fast-and slow-type fibers, identified by their tension response to pSr 5.0, BSA (0.7-15 µM) had no effect on the Ca 2+ affinity of the contractile proteins and elicited no tension per se in Ca 2+ -loaded fibers. In contrast, BSA (>1.0 µM) potentiated the caffeineinduced tension in Ca 2+ -loaded fibers, this effect being more intense in slow-type fibers. Thus, BSA reduced the threshold caffeine concentration required for eliciting detectable tension, and increased the amplitude, the rate of rise and the area under the curve of caffeine-induced tension. BSA also potentiated the tension elicited in Ca 2+ -loaded fibers by low-Mg 2+ solutions containing 1.0 mM free ATP. These results suggest that BSA modulates the response of the human skeletal muscle SR Ca 2+ -release channel to activators such as caffeine and ATP.

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Bovine serum albumin selectively increases the low-voltage-activated calcium current of NG108-15 neuroblastoma × glioma cells

Cited by 10 publications

References 17 publications

Cerebrospinal fluid and serum from patients with inflammatory polyradiculoneuropathy have opposite effects on sodium channels

Cerebrospinal fluid and serum from patients with inflammatory polyradiculoneuropathy have opposite effects on sodium channels

Effects of arachidonic acid on unitary calcium currents in rat sympathetic neurons

Bovine serum albumin potentiates caffeine- or ATP-induced tension in human skinned skeletal muscle fibers

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