scholarly journals Different Membrane Pathways Mediate Ca2+Influx in Adrenal Chromaffin Cells Exposed to 150–400 ns Electric Pulses

2018 ◽  
Vol 2018 ◽  
pp. 1-12 ◽  
Author(s):  
Tarique R. Bagalkot ◽  
Robert C. Terhune ◽  
Normand Leblanc ◽  
Gale L. Craviso
Keyword(s):  
Plasma Membrane ◽  
Pulse Width ◽  
Chromaffin Cells ◽  
Field Amplitude ◽  
Adrenal Chromaffin Cells ◽  
Rapid Rise ◽  
Electric Field Amplitude ◽  
Electric Pulses ◽  
Intracellular Ca ◽  
Adrenal Chromaffin

Exposing adrenal chromaffin cells to 5 ns electric pulses (nsPEF) causes a rapid rise in intracellular Ca2+(Ca2+i) that is solely the result of Ca2+influx through voltage-gated Ca2+channels (VGCCs). This study explored the effect of longer duration nsPEF onCa2+i. Single 150, 200, or 400 ns pulses at 3.1 kV/cm evoked rapid increases inCa2+i, the magnitude of which increased linearly with pulse width and electric field amplitude. Recovery ofCa2+ito prestimulus levels was faster for 150 ns exposures. Regardless of pulse width, no rise inCa2+ioccurred in the absence of extracellular Ca2+, indicating that the source of Ca2+was from outside the cell. Ca2+responses evoked by a 150 ns pulse were inhibited to varying degrees byω-agatoxin IVA,ω-conotoxin GVIA, nitrendipine or nimodipine, antagonists of P/Q-, N-, and L-type VGCCs, respectively, and by 67% when all four types of VGCCs were blocked simultaneously. The remaining Ca2+influx insensitive to VGCC inhibitors was attributed to plasma membrane nanoporation, which comprised theE-field sensitive component of the response. Both pathways of Ca2+entry were inhibited by 200 μM Cd2+. These results demonstrate that, in excitable chromaffin cells, single 150–400 ns pulses increased the permeability of the plasma membrane to Ca2+in addition to causing Ca2+influx via VGCCs.

scholarly journals Metabolic stability and antigenic modulation of nicotinic acetylcholine receptors on bovine adrenal chromaffin cells.

1988 ◽  
Vol 107 (3) ◽  
pp. 1147-1156 ◽  
Author(s):  
L S Higgins ◽  
D K Berg
Keyword(s):  
Plasma Membrane ◽  
Nicotinic Acetylcholine Receptors ◽  
Acetylcholine Receptors ◽  
Chromaffin Cells ◽  
Splanchnic Nerve ◽  
Temperature Sensitive ◽  
Adrenal Chromaffin Cells ◽  
Antigenic Modulation ◽  
Nicotinic Acetylcholine ◽  
Adrenal Chromaffin

Bovine adrenal chromaffin cells have nicotinic acetylcholine receptors (AChRs) that are activated by the splanchnic nerve, resulting in release of catecholamines from the cells. Examination of the AChRs can provide information about the regulation and turnover of synaptic components on neurons and endocrine cells. Previous studies have shown that mAb 35 recognizes the AChR on the cells. Here we show that mAb 35 can remove AChRs from the surface of the cells by antigenic modulation, and that the modulation can be used together with other methods to examine the stability and turnover of the receptors in the plasma membrane. Unexpectedly, the results indicate a disparity between the rate at which AChRs reappear on the cells and the rate at which the ACh response recovers after preexisting AChRs have been removed. Exposure of bovine adrenal chromaffin cultures to mAb 35 results in a parallel decrease in the magnitude of the nicotinic response and the number of AChRs on the cells. The decrease depends on the concentration and divalence of mAb 35, and on the time and temperature of the incubation. The antibody induces receptor aggregation in the plasma membrane under conditions where receptor loss subsequently occurs. After binding to receptor, mAb 35 appears to be internalized, degraded, and released from the cells through a temperature sensitive pathway that requires lysosomal function. These features are characteristic of antigenic modulation. Appearance of new AChRs on the cells either after antigenic modulation or after blockade of existing AChRs with monovalent antibody fragments occurs at a rate equivalent to 3% of the receptors present on control cells per hour. The rate of receptor loss from the cells was measured in the presence of either tunicamycin or puromycin to block appearance of new receptors. Both conditions indicated a receptor half-life of approximately 24 h and a rate of loss of approximately 3%/h. The finding that the rate of receptor loss equaled the rate of receptor appearance was consistent with the observation that the total number of AChRs on untreated cells did not increase with time. In the presence of tunicamycin, loss of receptor-mediated response to nicotine also occurred with a half-time of 24 h. Paradoxically, the rate of recovery of the nicotinic response, determined using two procedures, was more than twice as great as the rate at which new AChRs appeared on the cells.(ABSTRACT TRUNCATED AT 400 WORDS)

Plasma membrane lipids of bovine adrenal chromaffin cells

Lipids ◽  
1986 ◽  
Vol 21 (6) ◽  
pp. 417-419 ◽  
Author(s):  
A. N. Malviya ◽  
M. M. Gabellec ◽  
G. Rebel
Keyword(s):  
Plasma Membrane ◽  
Chromaffin Cells ◽  
Membrane Lipids ◽  
Adrenal Chromaffin Cells ◽  
Adrenal Chromaffin

scholarly journals Regulation of Ca2+ channels by SNAP-25 via recruitment of syntaxin-1 from plasma membrane clusters

2016 ◽  
Vol 27 (21) ◽  
pp. 3329-3341 ◽  
Author(s):  
Trine Lisberg Toft-Bertelsen ◽  
Iwona Ziomkiewicz ◽  
Sébastien Houy ◽  
Paulo S. Pinheiro ◽  
Jakob B. Sørensen
Keyword(s):  
Plasma Membrane ◽  
Chromaffin Cells ◽  
Botulinum Neurotoxin ◽  
Binding Protein ◽  
Expression Level ◽  
Cholesterol Depletion ◽  
Adrenal Chromaffin Cells ◽  
Adrenal Chromaffin ◽  
Ca2 Channels

SNAP-25 regulates Ca2+ channels, with potentially important consequences for diseases involving an aberrant SNAP-25 expression level. How this regulation is executed mechanistically remains unknown. We investigated this question in mouse adrenal chromaffin cells and found that SNAP-25 inhibits Ca2+ currents, with the B-isoform being more potent than the A-isoform, but not when syntaxin-1 is cleaved by botulinum neurotoxin C. In contrast, syntaxin-1 inhibits Ca2+ currents independently of SNAP-25. Further experiments using immunostaining showed that endogenous or exogenous SNAP-25 expression recruits syntaxin-1 from clusters on the plasma membrane, thereby increasing the immunoavailability of syntaxin-1 and leading indirectly to Ca2+ current inhibition. Expression of Munc18-1, which recruits syntaxin-1 within the exocytotic pathway, does not modulate Ca2+ channels, whereas overexpression of the syntaxin-binding protein Doc2B or ubMunc13-2 increases syntaxin-1 immunoavailability and concomitantly down-regulates Ca2+ currents. Similar findings were obtained upon chemical cholesterol depletion, leading directly to syntaxin-1 cluster dispersal and Ca2+ current inhibition. We conclude that clustering of syntaxin-1 allows the cell to maintain a high syntaxin-1 expression level without compromising Ca2+ influx, and recruitment of syntaxin-1 from clusters by SNAP-25 expression makes it available for regulating Ca2+ channels. This mechanism potentially allows the cell to regulate Ca2+ influx by expanding or contracting syntaxin-1 clusters.

scholarly journals Cyclic AMP-dependent mechanism regulates acetylcholine receptor function on bovine adrenal chromaffin cells and discriminates between new and old receptors.

1988 ◽  
Vol 107 (3) ◽  
pp. 1157-1165 ◽  
Author(s):  
L S Higgins ◽  
D K Berg
Keyword(s):  
Plasma Membrane ◽  
Nicotinic Acetylcholine Receptors ◽  
Acetylcholine Receptors ◽  
Chromaffin Cells ◽  
De Novo ◽  
Adrenal Chromaffin Cells ◽  
Secondary Messenger ◽  
Dependent Process ◽  
Adrenal Chromaffin ◽  
Antigenic Profile

Bovine adrenal chromaffin cells have nicotinic acetylcholine receptors (AChRs) that mediate release of catecholamines from the cells in response to synaptic input, and resemble neuronal AChRs in pharmacology and antigenic profile. Results presented here show that a cAMP-dependent process enhances the function of adrenal chromaffin AChRs as a population in the plasma membrane. This was demonstrated by showing that cAMP analogues cause specific increases both in the level of nicotine-induced catecholamine release from the cells and in the level of the nicotine-induced conductance change occurring in the cells. Neither de novo synthesis of receptors nor transport of preexisting intracellular receptors to the plasma membrane is necessary for the enhancement. The responsiveness of AChRs to regulation by the cAMP-dependent process appears to depend on the length of time the receptors have been on the cell surface. AChRs newly inserted into the plasma membrane generate a greater nicotinic response than do older AChRs and, unlike older AChRs, their response to agonist is not enhanced after treatment of the cells with cAMP analogues. The findings indicate that the AChRs and/or associated components undergo a maturation in the plasma membrane that alters their function and their regulation by secondary messenger systems.

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