Amperometric Study of the Kinetics of Exocytosis in Mouse Adrenal Slice Chromaffin Cells: Physiological and Methodological Insights

2006 ◽  
Vol 96 (3) ◽  
pp. 1196-1202 ◽  
Author(s):  
Gloria Arroyo ◽  
Jorge Fuentealba ◽  
Natalia Sevane-Fernández ◽  
Marcos Aldea ◽  
Antonio G. García ◽  
...  
Keyword(s):  
Electrical Stimulation ◽  
Carbon Fiber ◽  
Phosphate Buffer ◽  
Neurotransmitter Release ◽  
Chromaffin Cells ◽  
Nicotinic Receptors ◽  
Adrenal Glands ◽  
Splanchnic Nerve ◽  
Amperometric Response ◽  
Kinetics Of

This study was designed to examine the kinetics of neurotransmitter release using the carbon fiber amperometric technique on cells in slices of mouse adrenal glands superfused with bicarbonate phosphate buffer–based solutions. The exocytotic amperometric response evoked by electrical stimulation was significantly faster than that produced after exogenous application of ACh or K+. Splanchnic nerve–evoked neurotransmitter release was blocked by hexamethonium, indicating the involvement of ACh nicotinic receptors. We discuss the implications of our data for understanding the mechanisms underlying the vesicle fusion process.

scholarly journals Role of cholinergic receptors in adrenal catecholamine secretion in spontaneously hypertensive rats

1999 ◽  
Vol 277 (4) ◽  
pp. R1057-R1062 ◽  
Author(s):  
Takahiro Nagayama ◽  
Takayuki Matsumoto ◽  
Makoto Yoshida ◽  
Mizue Suzuki-Kusaba ◽  
Hiroaki Hisa ◽  
...  
Keyword(s):  
Electrical Stimulation ◽  
Muscarinic Receptors ◽  
Nicotinic Receptors ◽  
Spontaneously Hypertensive Rats ◽  
Adrenal Glands ◽  
Hypertensive Rats ◽  
Spontaneously Hypertensive ◽  
Wky Rats ◽  
Wistar Kyoto

We investigated the role of nicotinic and muscarinic receptors in secretion of catecholamines induced by transmural electrical stimulation (ES) from isolated perfused adrenal glands of spontaneously hypertensive rats (SHRs) and normotensive Wistar-Kyoto (WKY) rats. ES (1–10 Hz) produced frequency-dependent increases in epinephrine (Epi) and norepinephrine (NE) output as measured in perfusate. The ES-induced increases in NE output, but not Epi output, were significantly greater in adrenal glands of SHRs than in those of WKY rats. Hexamethonium (10–100 μM) markedly inhibited the ES-induced increases in Epi and NE output from adrenal glands of SHRs and WKY rats. Atropine (0.3–3 μM) inhibited the ES-induced increases in Epi and NE output from adrenal glands of SHRs, but not from those of WKY rats. These results suggest that endogenous acetylcholine-induced secretion of adrenal catecholamines is predominantly mediated by nicotinic receptors in SHRs and WKY rats and that the contribution of muscarinic receptors may be different between these two strains.

scholarly journals Full activation of an α7-α3β4 nicotinic receptor complex avoids receptor desensitization in human chromaffin cells

2020 ◽  
Author(s):  
Amanda Jiménez-Pompa ◽  
Sara Sanz-Lázaro ◽  
José Medina-Polo ◽  
Carmen González-Enguita ◽  
Jesús Blázquez ◽  
...  
Keyword(s):  
Nicotinic Receptor ◽  
Chromaffin Cells ◽  
Nicotinic Receptors ◽  
Adrenal Glands ◽  
Gradual Increase ◽  
Receptor Complex ◽  
Receptor Desensitization ◽  
Partial Activation ◽  
Full Activation

Abstractα7 nicotinic receptors have been involved in numerous pathologies. A hallmark of these receptors is their extremely fast desensitization, a process not fully understood yet. Here we show that human native α7 and α3β4 nicotinic receptors physically interact in human chromaffin cells of adrenal glands. The full activation of this α7-α3β4 receptor complex avoids subtypes receptor desensitization, leading to gradual increase of currents with successive acetylcholine pulses. Instead, full and partial activation with choline of α7 and α3β4 subtypes, respectively, of this linked receptor leads to α7 receptor desensitization. Therefore choline, a product of the acetylcholine hydrolysis, acts as a brake by limiting the increase of currents by acetylcholine. Very importantly, the efficiency of the α7-α3β4 interaction diminishes in subjets older than 50 years, accordingly increasing receptor desensitization and decreasing nicotinic currents. These results open a new line of research to achieve improved therapeutic treatments for nicotinic receptors related diseases.

PACAP-(1–38) as neurotransmitter in the porcine adrenal glands

2000 ◽  
Vol 279 (6) ◽  
pp. E1413-E1425 ◽  
Author(s):  
Karen Tornøe ◽  
Jens Hannibal ◽  
Tine Børglum Jensen ◽  
Birgitte Georg ◽  
Lars Fledelius Rickelt ◽  
...  
Keyword(s):  
Chromaffin Cells ◽  
Endocrine Cells ◽  
Adrenal Glands ◽  
Fold Increase ◽  
Splanchnic Nerve ◽  
Reflex Pathways ◽  
Calcitonin Gene ◽  
Adrenal Chromaffin ◽  
Adrenal Secretion ◽  
Splanchnic Nerve Stimulation

The concentration of pituitary adenylyl cyclase-activating polypeptide [PACAP-(1–38)] in porcine adrenal glands amounted to 14 ± 3 pmol/g tissue. PACAP immunoreactive (PACAP-IR) fibers innervated adrenal chromaffin cells (often co-localized with choline acetyltransferase). Subcapsular fibers traversed the cortex-innervating endocrine cells and blood vessels [some co-storing mainly calcitonin gene-related peptide but also vasoactive intestinal polypeptide (VIP)]. PACAP-IR fibers were demonstrated in the splanchnic nerves, whereas IR adrenal nerve cell bodies were absent. In isolated, vascularly perfused adrenal gland, splanchnic nerve stimulation (16 Hz) and capsaicin (10−5 M) increased PACAP-(1–38) release (1.6-fold and 6-fold respectively, P = 0.02). PACAP-(1–38) dose-dependently stimulated cortisol (2 × 10−10 M; 24-fold increase, P = 0.02) and chromogranin A fragment (2 × 10−9 M; 15-fold increase, P = 0.05) secretion. Both were strongly inhibited by the PAC1/VPAC2 receptor antagonist PACAP-(6–38) (10−7 M). PACAP-(6–38) also inhibited splanchnic nerve (10 Hz)-induced cortisol secretion but lacked any effect on splanchnic nerve-induced pancreastatin secretion. PACAP-(1–38) (2 × 10−10 M) decreased vascular resistance from 5.5 ± 0.6 to 4.6 ± 0.4 mmHg · min · ml−1. PACAP-(6–38) had no effect on this response. We conclude that PACAP-(1–38) may play a role in splanchnic nerve-induced adrenal secretion and in afferent reflex pathways.

scholarly journals The V-ATPase membrane domain is a sensor of granular pH that controls the exocytotic machinery

2013 ◽  
Vol 203 (2) ◽  
pp. 283-298 ◽  
Author(s):  
Sandrine Poëa-Guyon ◽  
Mohamed Raafet Ammar ◽  
Marie Erard ◽  
Muriel Amar ◽  
Alexandre W. Moreau ◽  
...  
Keyword(s):  
Neurotransmitter Release ◽  
Chromaffin Cells ◽  
Secretory Granules ◽  
Secretory Vesicle ◽  
Fusion Pore ◽  
Membrane Domain ◽  
Reversible Dissociation ◽  
Open Time ◽  
Vesicle Exocytosis ◽  
Kinetics Of

Several studies have suggested that the V0 domain of the vacuolar-type H+-adenosine triphosphatase (V-ATPase) is directly implicated in secretory vesicle exocytosis through a role in membrane fusion. We report in this paper that there was a rapid decrease in neurotransmitter release after acute photoinactivation of the V0 a1-I subunit in neuronal pairs. Likewise, inactivation of the V0 a1-I subunit in chromaffin cells resulted in a decreased frequency and prolonged kinetics of amperometric spikes induced by depolarization, with shortening of the fusion pore open time. Dissipation of the granular pH gradient was associated with an inhibition of exocytosis and correlated with the V1–V0 association status in secretory granules. We thus conclude that V0 serves as a sensor of intragranular pH that controls exocytosis and synaptic transmission via the reversible dissociation of V1 at acidic pH. Hence, the V-ATPase membrane domain would allow the exocytotic machinery to discriminate fully loaded and acidified vesicles from vesicles undergoing neurotransmitter reloading.

Fusion and Fission Processes in Exocytosis: Possible Roles for Synexin and Osmotic Lysis in the Two Events

1980 ◽  
Vol 38 ◽  
pp. 594-597
Author(s):  
H.B. Pollard ◽  
C.E. Creutz ◽  
C.J. Pazoles ◽  
J.H. Scott
Keyword(s):  
Small Molecules ◽  
Chromaffin Cells ◽  
Adrenal Glands ◽  
General Concept ◽  
Extracellular Calcium ◽  
Large Protein ◽  
Granule Membrane ◽  
Osmotic Lysis ◽  
Per Se ◽  
Chemical Evidence

Exocytosis is a general concept describing secretion of enzymes, hormones and transmitters that are otherwise sequestered in intracellular granules. Chemical evidence for this concept was first gathered from studies on chromaffin cells in perfused adrenal glands, in which it was found that granule contents, including both large protein and small molecules such as adrenaline and ATP, were released together while the granule membrane was retained in the cell. A number of exhaustive reviews of this early work have been published and are summarized in Reference 1. The critical experiments demonstrating the importance of extracellular calcium for exocytosis per se were also first performed in this system (2,3), further indicating the substantial service given by chromaffin cells to those interested in secretory phenomena over the years.

Viral inactivation by potassium ferrate

1995 ◽  
Vol 31 (5-6) ◽  
pp. 165-168 ◽  
Author(s):  
Futaba Kazama
Keyword(s):  
Phosphate Buffer ◽  
Potassium Ferrate ◽  
Sodium Thiosulphate ◽  
Viral Inactivation ◽  
Complete Decomposition ◽  
Kinetics Of ◽  
Oxidative Intermediate

The kinetics of inactivation by potassium ferrate were studied using a bacteriophage, F-specific RNA-coliphage Qβ as a viral model. The inactivation appeared to be expressed by Hom's model in phosphate buffer at pH 6, 7, and 8. The rate of inactivation depended on pH; the lower pH, the faster inactivation observed. To consider the mechanism by which ferrate caused inactivation, the efficiency of inactivation was checked after ferrate decomposition in buffer. Effective inactivation following Hom's model was also observed after the complete decomposition of ferrate ion; however, the efficiency of that inactivation disappeared by the addition of sodium thiosulphate, suggesting that rather long-lived oxidative intermediate was generated by the decomposition of ferrate ion. The intermediate might take part in the inactivation.

Effect of phosphate buffer on the kinetics of glycation of proteins

2005 ◽  
Vol 18 (2) ◽  
pp. 183-186 ◽  
Author(s):  
Herminia Gil ◽  
Daniel Salcedo ◽  
Rom�n Romero
Keyword(s):  
Phosphate Buffer ◽  
Kinetics Of

Faster kinetics of quantal catecholamine release in mouse chromaffin cells stimulated with acetylcholine, compared with other secretagogues

2016 ◽  
Vol 139 (5) ◽  
pp. 722-736 ◽  
Author(s):  
Enrique Calvo-Gallardo ◽  
Ángela López-Gil ◽  
Iago Méndez-López ◽  
Carmen Martínez-Ramírez ◽  
Juan Fernando Padín ◽  
...  
Keyword(s):  
Chromaffin Cells ◽  
Catecholamine Release ◽  
Kinetics Of
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