scholarly journals gamma-Aminobutyric acid receptor channels in adrenal chromaffin cells: a patch-clamp study.

1985 ◽  
Vol 82 (7) ◽  
pp. 2168-2172 ◽  
Author(s):  
J. Bormann ◽  
D. E. Clapham
Keyword(s):  
Patch Clamp ◽  
Chromaffin Cells ◽  
Aminobutyric Acid ◽  
Gamma Aminobutyric Acid ◽  
Adrenal Chromaffin Cells ◽  
Acid Receptor ◽  
Adrenal Chromaffin ◽  
Clamp Study

scholarly journals Patch clamp study on dopaminergic inhibition of adrenal chromaffin cells

1989 ◽  
Vol 49 ◽  
pp. 178
Author(s):  
Yasutake Mine ◽  
Akinori Akaike ◽  
Masashi Sasa ◽  
Shuji Takaori
Keyword(s):  
Patch Clamp ◽  
Chromaffin Cells ◽  
Adrenal Chromaffin Cells ◽  
Adrenal Chromaffin ◽  
Clamp Study

Calcium entry through slow-inactivating L-type calcium channels preferentially triggers endocytosis rather than exocytosis in bovine chromaffin cells

2011 ◽  
Vol 301 (1) ◽  
pp. C86-C98 ◽  
Author(s):  
Juliana M. Rosa ◽  
Cristina J. Torregrosa-Hetland ◽  
Inés Colmena ◽  
Luis M. Gutiérrez ◽  
Antonio G. García ◽  
...  
Keyword(s):  
Patch Clamp ◽  
Chromaffin Cells ◽  
Channel Blocker ◽  
Primary Cultures ◽  
Adrenal Chromaffin Cells ◽  
Cell Functions ◽  
Fluorescence Techniques ◽  
Voltage Dependent ◽  
Bovine Chromaffin Cells ◽  
Adrenal Chromaffin

Calcium (Ca2+)-dependent endocytosis has been linked to preferential Ca2+ entry through the L-type (α1D, CaV1.3) of voltage-dependent Ca2+ channels (VDCCs). Considering that the Ca2+-dependent exocytotic release of neurotransmitters is mostly triggered by Ca2+ entry through N-(α1B, CaV2.2) or PQ-VDCCs (α1A, CaV2.1) and that exocytosis and endocytosis are coupled, the supposition that the different channel subtypes are specialized to control different cell functions is attractive. Here we have explored this hypothesis in primary cultures of bovine adrenal chromaffin cells where PQ channels account for 50% of Ca2+ current ( ICa), 30% for N channels, and 20% for L channels. We used patch-clamp and fluorescence techniques to measure the exo-endocytotic responses triggered by long depolarizing stimuli, in 1, 2, or 10 mM concentrations of extracellular Ca2+ ([Ca2+]e). Exo-endocytotic responses were little affected by ω-conotoxin GVIA (N channel blocker), whereas ω-agatoxin IVA (PQ channel blocker) caused 80% blockade of exocytosis as well as endocytosis. In contrast, nifedipine (L channel blocker) only caused 20% inhibition of exocytosis but as much as 90% inhibition of endocytosis. Conversely, FPL67146 (an activator of L VDCCs) notably augmented endocytosis. Photoreleased caged Ca2+ caused substantially smaller endocytotic responses compared with those produced by K+ depolarization. Using fluorescence antibodies, no colocalization between L, N, or PQ channels with clathrin was found; a 20–30% colocalization was found between dynamin and all three channel antibodies. This is incompatible with the view that L channels are coupled to the endocytotic machine. Data rather support a mechanism implying the different inactivation rates of L (slow-inactivating) and N/PQ channels (fast-inactivating). Thus a slow but more sustained Ca2+ entry through L channels could be a requirement to trigger endocytosis efficiently, at least in bovine chromaffin cells.

scholarly journals Stimulus-secretion coupling in excitable cells: a central role for calcium

1993 ◽  
Vol 184 (1) ◽  
pp. 183-196 ◽  
Author(s):  
T. R. Cheek ◽  
V. A. Barry
Keyword(s):  
Patch Clamp ◽  
Chromaffin Cells ◽  
Calcium Concentration ◽  
Flash Photolysis ◽  
Secretory Cells ◽  
Adrenal Chromaffin Cells ◽  
Excitable Cells ◽  
Stimulus Secretion Coupling ◽  
Adrenal Chromaffin ◽  
Dependent Processes

Secretion of vesicular contents by exocytosis is a common feature of neuroendocrine secretory cells such as adrenal chromaffin cells and PC12 cells. Although it is clear that in these cells an elevation in intracellular calcium concentration, [Ca2+]i, is the triggering event that induces secretion, recent studies using video-imaging, patch-clamp and flash photolysis techniques have all indicated that the Ca2+ signal that triggers secretion is in fact very complex, with the subcellular distribution of Ca2+ being of particular importance along with the magnitude of the rise. It has become evident that Ca2+ signals with different spatial profiles can be triggered in the same cell by a given stimulus, depending upon the nature of the Ca2+ signalling pathway activated, and that this ability to be able to vary the method of delivery of Ca2+ into the cell is important physiologically, because it provides a means of obtaining differential activation of Ca(2+)-dependent processes.

Patch-clamp capacitance analysis of the effects of alpha-SNAP on exocytosis in adrenal chromaffin cells

1996 ◽  
Vol 109 (9) ◽  
pp. 2417-2422
Author(s):  
A.V. Kibble ◽  
R.J. Barnard ◽  
R.D. Burgoyne
Keyword(s):  
Patch Clamp ◽  
Chromaffin Cells ◽  
Deletion Mutant ◽  
Initial Rate ◽  
Membrane Capacitance ◽  
Adrenal Chromaffin Cells ◽  
Pipette Solution ◽  
Whole Cell ◽  
Whole Cell Patch Clamp ◽  
Adrenal Chromaffin

We have examined the effect of alpha-SNAP on exocytosis in adrenal chromaffin cells by direct assay of exocytosis using patch-clamp capacitance analysis. Cells were recorded using the whole cell patch-clamp configuration and the cells dialysed with control pipette solution or with a pipette solution containing alpha-SNAP or the deletion mutant alpha-SNAP(41–295). The deletion mutant was found to be unable to bind to syntaxin allowing a test of the requirement for syntaxin-binding for any effect of alpha-SNAP on exocytosis. Following cell dialysis for 10 minutes, cells were depolarised five times at 2 minute intervals. At each depolarisation step cells dialysed with alpha-SNAP showed a significant increase in both the initial rate and extent of exocytosis which was seen as a rise in membrane capacitance. This increase in exocytosis was not observed with alpha-SNAP(41–295) which instead produced some inhibition of the extent but had no effect on the initial rate of exocytosis. These results show directly that alpha-SNAP has a specific and marked stimulatory effect on exocytosis in chromaffin cells.

Morphological Observations on the Granule Types in Rabbit Extra-Adrenal Chromaffin Cells.

1975 ◽  
Vol 33 ◽  
pp. 318-319
Author(s):  
Joe A. Mascorro ◽  
Robert D. Yates
Keyword(s):  
Chromaffin Cells ◽  
Sodium Phosphate ◽  
Ganglion Cells ◽  
Ultrastructural Level ◽  
Osmic Acid ◽  
Adrenal Chromaffin Cells ◽  
Potassium Iodate ◽  
Perfusion Fluid ◽  
New Zealand White Rabbits ◽  
Adrenal Chromaffin

Extra-adrenal chromaffin organs (abdominal paraganglia) constitute rich sources of catecholamines. It is believed that these bodies contain norepinephrine exclusively. However, the present workers recently observed epinephrine type granules in para- ganglion cells. This report investigates catecholamine containing granules in rabbit paraganglia at the ultrastructural level.New Zealand white rabbits (150-170 grams) were anesthetized with 50 mg/kg Nembutal (IP) and perfused with 3% glutaraldehyde buffered with 0.2M sodium phosphate, pH 7.3. The retroperitoneal tissue blocks were removed and placed in perfusion fluid for 4 hours. The abdominal paraganglia were dissected from the blocks, diced, washed in phosphate buffer and fixed in 1% osmic acid buffered with phosphate. In other animals, the glutaraldehyde perfused tissue blocks were immersed for 1 hour in 3% glutaraldehyde/2.5% potassium iodate buffered as before. The paraganglia were then diced, separated into two vials and washed in the buffer. A portion of this tissue received osmic acid fixation.

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