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Gil A, González-Vélez V, Gutiérrez LM, Villanueva J. The Role of Nicotinic Receptors on Ca 2+ Signaling in Bovine Chromaffin Cells. Curr Issues Mol Biol 2024; 46:808-820. [PMID: 38248354 PMCID: PMC10814139 DOI: 10.3390/cimb46010052] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2023] [Revised: 01/03/2024] [Accepted: 01/12/2024] [Indexed: 01/23/2024] Open
Abstract
Chromaffin cells have been used as a physiological model to understand neurosecretion in mammals for many years. Nicotinic receptors located in the cells' membrane are stimulated by acetylcholine, and they participate in the exocytosis of chromaffin granules, releasing catecholamines in response to stress. In this work, we discuss how the participation of nicotinic receptors and the localization of active zones in the borders of the cytoskeleton can generate local calcium signals leading to secretion. We use a computational model of a cytoskeleton cage to simulate Ca2+ levels in response to voltage and acetylcholine pulses. We find that nicotinic receptors are able to enhance the differences between local and average calcium values, as well as the heterogeneous distributions around the active zones, producing a non-linear, highly localized Ca2+ entry that, although consisting of a few ions, is able to improve secretion responses in chromaffin cells. Our findings emphasize the intricate interplay among nicotinic receptors, the cytoskeleton, and active zones within chromaffin cells as an example of Ca2+-dependent neurosecretion in mammals.
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Affiliation(s)
- Amparo Gil
- Departamento de Matemática Aplicada y CC de la Computación, Universidad de Cantabria, 39005 Santander, Spain;
| | - Virginia González-Vélez
- Departamento Ciencias Básicas, Universidad Autónoma Metropolitana Azcapotzalco, Mexico City 02128, Mexico
| | - Luis Miguel Gutiérrez
- Instituto de Neurociencias, CSIC-Universidad Miguel Hernández. Ctra de Valencia S/N, Sant Joan d’Alacant, 03550 Alicante, Spain;
| | - José Villanueva
- Instituto de Neurociencias, CSIC-Universidad Miguel Hernández. Ctra de Valencia S/N, Sant Joan d’Alacant, 03550 Alicante, Spain;
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López-Gil A, Nanclares C, Méndez-López I, Martínez-Ramírez C, de Los Rios C, Padín-Nogueira JF, Montero M, Gandía L, García AG. The quantal catecholamine release from mouse chromaffin cells challenged with repeated ACh pulses is regulated by the mitochondrial Na + /Ca 2+ exchanger. J Physiol 2017; 595:2129-2146. [PMID: 27982456 DOI: 10.1113/jp273339] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2016] [Accepted: 11/30/2016] [Indexed: 01/09/2023] Open
Abstract
KEY POINTS Upon repeated application of short ACh pulses to C57BL6J mouse chromaffin cells, the amperometrically monitored secretory responses promptly decayed to a steady-state level of around 25% of the initial response. A subsequent K+ pulse, however, overcame such decay. These data suggest that mouse chromaffin cells have a ready release-vesicle pool that is selectively recruited by the physiological neurotransmitter ACh. The ACh-sensitive vesicle pool is refilled and maintained by the rate of Ca2+ delivery from mitochondria to the cytosol, through the mitochondrial Na+ /Ca2+ exchanger (mNCX). ITH12662, a novel blocker of the mNCX, prevented the decay of secretion elicited by ACh pulses and delayed the rate of [Ca2+ ]c clearance. This regulatory pathway may be physiologically relevant in situations of prolonged stressful conflicts where a sustained catecholamine release is regulated by mitochondrial Ca2+ circulation through the mNCX, which couples respiration and ATP synthesis to long-term stimulation of chromaffin cells by endogenously released ACh. ABSTRACT Using caged-Ca2+ photorelease or paired depolarising pulses in voltage-clamped chromaffin cells (CCs), various pools of secretory vesicles with different readiness to undergo exocytosis have been identified. Whether these pools are present in unclamped CCs challenged with ACh, the physiological neurotransmitter at the splanchnic nerve-CC synapse, is unknown. We have explored here whether an ACh-sensitive ready-release vesicle pool (ASP) is present in C57BL6J mouse chromaffin cells (MCCs). Single cells were fast perfused with a Tyrode solution at 37°C, and challenged with 12 sequential ACh pulses (100 μm, 2 s, every 30 s) plus a K+ pulse given at the end (75 mm K+ ). After the first 2-3 ACh pulses the amperometrically monitored secretory responses promptly decayed to a steady-state level of around 25% of the initial response. The last K+ pulse, however, overcame such decay. Repeated ACh pulses to voltage-clamped cells elicited non-desensitising nicotinic currents. Also, the [Ca2+ ]c transients elicited by repeated ACh pulses that were superimposed on a stable baseline elevation did not undergo decay. The novel blocker of the mitochondrial Na+ /Ca2+ exchanger (mNCX) ITH12662 prevented the decay of secretion elicited by ACh pulses and delayed the rate of [Ca2+ ]c clearance. The experiments are compatible with the idea that C57BL6J MCCs have an ASP vesicle pool that is selectively recruited by the physiological neurotransmitter ACh and is regulated by the rate of Ca2+ delivery from mitochondria to the cytosol, through the mNCX.
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Affiliation(s)
- Angela López-Gil
- Instituto Teófilo Hernando, Universidad Autónoma de Madrid, C/ Arzobispo Morcillo, 4, 28029, Madrid, Spain
| | - Carmen Nanclares
- Instituto Teófilo Hernando, Universidad Autónoma de Madrid, C/ Arzobispo Morcillo, 4, 28029, Madrid, Spain.,Departamento de Farmacología y Terapéutica, Facultad de Medicina, Universidad Autónoma de Madrid, C/ Arzobispo Morcillo, 4, 28029, Madrid, Spain
| | - Iago Méndez-López
- Instituto Teófilo Hernando, Universidad Autónoma de Madrid, C/ Arzobispo Morcillo, 4, 28029, Madrid, Spain.,Departamento de Farmacología y Terapéutica, Facultad de Medicina, Universidad Autónoma de Madrid, C/ Arzobispo Morcillo, 4, 28029, Madrid, Spain
| | - Carmen Martínez-Ramírez
- Instituto Teófilo Hernando, Universidad Autónoma de Madrid, C/ Arzobispo Morcillo, 4, 28029, Madrid, Spain.,Departamento de Farmacología y Terapéutica, Facultad de Medicina, Universidad Autónoma de Madrid, C/ Arzobispo Morcillo, 4, 28029, Madrid, Spain
| | - Cristóbal de Los Rios
- Instituto Teófilo Hernando, Universidad Autónoma de Madrid, C/ Arzobispo Morcillo, 4, 28029, Madrid, Spain.,Instituto de Investigación Sanitaria, Hospital Universitario de la Princesa, Universidad Autónoma de Madrid, c/ Diego de León, 62, 28006, Madrid, Spain
| | - J Fernando Padín-Nogueira
- Instituto Teófilo Hernando, Universidad Autónoma de Madrid, C/ Arzobispo Morcillo, 4, 28029, Madrid, Spain.,Departamento de Farmacología y Terapéutica, Facultad de Medicina, Universidad Autónoma de Madrid, C/ Arzobispo Morcillo, 4, 28029, Madrid, Spain
| | - Mayte Montero
- Instituto de Biologia y Genética Molecular, Universidad de Valladolid, c/ Sanz y Forés, 3, 47003, Valladolid, Spain
| | - Luis Gandía
- Instituto Teófilo Hernando, Universidad Autónoma de Madrid, C/ Arzobispo Morcillo, 4, 28029, Madrid, Spain.,Departamento de Farmacología y Terapéutica, Facultad de Medicina, Universidad Autónoma de Madrid, C/ Arzobispo Morcillo, 4, 28029, Madrid, Spain
| | - Antonio G García
- Instituto Teófilo Hernando, Universidad Autónoma de Madrid, C/ Arzobispo Morcillo, 4, 28029, Madrid, Spain.,Departamento de Farmacología y Terapéutica, Facultad de Medicina, Universidad Autónoma de Madrid, C/ Arzobispo Morcillo, 4, 28029, Madrid, Spain.,Instituto de Investigación Sanitaria, Hospital Universitario de la Princesa, Universidad Autónoma de Madrid, c/ Diego de León, 62, 28006, Madrid, Spain
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