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How does the stimulus define exocytosis in adrenal chromaffin cells? Pflugers Arch 2017; 470:155-167. [DOI: 10.1007/s00424-017-2052-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2017] [Revised: 07/28/2017] [Accepted: 08/01/2017] [Indexed: 12/28/2022]
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Moya-Díaz J, Álvarez YD, Montenegro M, Bayonés L, Belingheri AV, González-Jamett AM, Cárdenas AM, Marengo FD. Sustained Exocytosis after Action Potential-Like Stimulation at Low Frequencies in Mouse Chromaffin Cells Depends on a Dynamin-Dependent Fast Endocytotic Process. Front Cell Neurosci 2016; 10:184. [PMID: 27507935 PMCID: PMC4960491 DOI: 10.3389/fncel.2016.00184] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2016] [Accepted: 07/08/2016] [Indexed: 12/17/2022] Open
Abstract
Under basal conditions the action potential firing rate of adrenal chromaffin cells is lower than 0.5 Hz. The maintenance of the secretory response at such frequencies requires a continuous replenishment of releasable vesicles. However, the mechanism that allows such vesicle replenishment remains unclear. Here, using membrane capacitance measurements on mouse chromaffin cells, we studied the mechanism of replenishment of a group of vesicles released by a single action potential-like stimulus (APls). The exocytosis triggered by APls (ETAP) represents a fraction (40%) of the immediately releasable pool, a group of vesicles highly coupled to voltage dependent calcium channels. ETAP was replenished with a time constant of 0.73 ± 0.11 s, fast enough to maintain synchronous exocytosis at 0.2–0.5 Hz stimulation. Regarding the mechanism involved in rapid ETAP replenishment, we found that it depends on the ready releasable pool; indeed depletion of this vesicle pool significantly delays ETAP replenishment. On the other hand, ETAP replenishment also correlates with a dynamin-dependent fast endocytosis process (τ = 0.53 ± 0.01 s). In this regard, disruption of dynamin function markedly inhibits the fast endocytosis and delays ETAP replenishment, but also significantly decreases the synchronous exocytosis during repetitive APls stimulation at low frequencies (0.2 and 0.5 Hz). Considering these findings, we propose a model in where both the transfer of vesicles from ready releasable pool and fast endocytosis allow rapid ETAP replenishment during low stimulation frequencies.
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Affiliation(s)
- José Moya-Díaz
- Departamento de Fisiología y Biología Molecular y Celular, Facultad de Ciencias Exactas y Naturales, Instituto de Fisiología, Biología Molecular y Neurociencias, Universidad de Buenos Aires, Consejo Nacional de Investigaciones Científicas y Técnicas Buenos Aires, Argentina
| | - Yanina D Álvarez
- Departamento de Fisiología y Biología Molecular y Celular, Facultad de Ciencias Exactas y Naturales, Instituto de Fisiología, Biología Molecular y Neurociencias, Universidad de Buenos Aires, Consejo Nacional de Investigaciones Científicas y Técnicas Buenos Aires, Argentina
| | - Mauricio Montenegro
- Departamento de Fisiología y Biología Molecular y Celular, Facultad de Ciencias Exactas y Naturales, Instituto de Fisiología, Biología Molecular y Neurociencias, Universidad de Buenos Aires, Consejo Nacional de Investigaciones Científicas y Técnicas Buenos Aires, Argentina
| | - Lucas Bayonés
- Departamento de Fisiología y Biología Molecular y Celular, Facultad de Ciencias Exactas y Naturales, Instituto de Fisiología, Biología Molecular y Neurociencias, Universidad de Buenos Aires, Consejo Nacional de Investigaciones Científicas y Técnicas Buenos Aires, Argentina
| | - Ana V Belingheri
- Departamento de Fisiología y Biología Molecular y Celular, Facultad de Ciencias Exactas y Naturales, Instituto de Fisiología, Biología Molecular y Neurociencias, Universidad de Buenos Aires, Consejo Nacional de Investigaciones Científicas y Técnicas Buenos Aires, Argentina
| | - Arlek M González-Jamett
- Centro Interdisciplinario de Neurociencia de Valparaíso, Facultad de Ciencias, Universidad de Valparaíso Valparaíso, Chile
| | - Ana M Cárdenas
- Centro Interdisciplinario de Neurociencia de Valparaíso, Facultad de Ciencias, Universidad de Valparaíso Valparaíso, Chile
| | - Fernando D Marengo
- Departamento de Fisiología y Biología Molecular y Celular, Facultad de Ciencias Exactas y Naturales, Instituto de Fisiología, Biología Molecular y Neurociencias, Universidad de Buenos Aires, Consejo Nacional de Investigaciones Científicas y Técnicas Buenos Aires, Argentina
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Cárdenas AM, Marengo FD. How the stimulus defines the dynamics of vesicle pool recruitment, fusion mode, and vesicle recycling in neuroendocrine cells. J Neurochem 2016; 137:867-79. [DOI: 10.1111/jnc.13565] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2015] [Revised: 01/05/2016] [Accepted: 01/25/2016] [Indexed: 01/08/2023]
Affiliation(s)
- Ana María Cárdenas
- Centro Interdisciplinario de Neurociencia de Valparaíso; Universidad de Valparaíso; Valparaíso Chile
| | - Fernando D. Marengo
- Laboratorio de Fisiología y Biología Molecular; Instituto de Fisiología; Biología Molecular y Neurociencias (CONICET); Departamento de Fisiología y Biología Molecular y Celular; Facultad de Ciencias Exactas y Naturales; Universidad de Buenos Aires; Buenos Aires Argentina
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Alvarez YD, Ibañez LI, Uchitel OD, Marengo FD. P/Q Ca2+ channels are functionally coupled to exocytosis of the immediately releasable pool in mouse chromaffin cells. Cell Calcium 2008; 43:155-64. [PMID: 17561253 DOI: 10.1016/j.ceca.2007.04.014] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2006] [Revised: 04/26/2007] [Accepted: 04/27/2007] [Indexed: 11/18/2022]
Abstract
Chromaffin cell exocytosis is triggered by Ca(2+) entry through several voltage-dependent channel subtypes. Because it was postulated that immediately releasable vesicles are closely associated with Ca(2+) channels, we wondered what channel types are specifically coupled to the release of this pool. To study this question, cultured mouse chromaffin cell exocytosis was followed by patch-clamp membrane capacitance measurements. The immediately releasable pool was estimated using paired pulse stimulation, resulting in an upper limit of 31+/-3 fF for control conditions (I(Ca): 25+/-2 pA/pF). The N-type channel blocker omega-conotoxin-GVIA affected neither I(Ca) nor the immediately releasable pool exocytosis; although the L channel blocker nitrendipine decreased current by 50%, it did not reduce this pool significantly; and the R channel inhibitor SNX-482 significantly reduced the current but induced only a moderate decrease in the estimated IRP exocytosis. In contrast, the P/Q channel blocker omega-Agatoxin-IVA decreased I(Ca) by 37% but strongly reduced the immediately releasable pool (upper limit: 6+/-1 fF). We used alpha1A subunit knockout mice to corroborate that P/Q Ca(2+) channels were specifically linked to immediately releasable vesicles, and we found that also in this preparation the exocytosis of this pool was severely decreased (6+/-1 fF). On the other hand, application of a strong stimulus that caused the fusion of most of releasable vesicles (3 min, 50 mM K(+)) induced similar exocytosis for wild type and knockout cells. Finally, whereas application of train stimulation on chromaffin cells derived from wild type mice provoked typical early synchronous and delayed asynchronous exocytosis components, the knockout derived cells presented a strongly depressed early exocytosis but showed a prominent delayed asynchronous component. These results demonstrate that P/Q are the dominant calcium channels associated to the release of immediately releasable pool in mouse chromaffin cells.
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Affiliation(s)
- Yanina D Alvarez
- Instituto de Fisiología, Biología Molecular y Neurociencias (CONICET), Departamento de Fisiología y Biología Molecular y Celular, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Argentina
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Berestovsky GN, Kataev AA, Tsyganov MA. Transient currents and Ca2+ gradient relaxation in characean algae cells: Theory and experiment. Biophysics (Nagoya-shi) 2006. [DOI: 10.1134/s0006350906060042] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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Oheim M, Kirchhoff F, Stühmer W. Calcium microdomains in regulated exocytosis. Cell Calcium 2006; 40:423-39. [PMID: 17067670 DOI: 10.1016/j.ceca.2006.08.007] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2006] [Accepted: 08/23/2006] [Indexed: 11/19/2022]
Abstract
Katz and co-workers showed that Ca(2+) triggers exocytosis. The existence of sub-micrometer domains of greater than 100 microM [Ca(2+)](i) was postulated on theoretical grounds. Using a modified, low-affinity aequorin, Llinas et al. were the first to demonstrate the existence of Ca(2+) 'microdomains' in squid presynaptic terminals. Over the past several years, it has become clear that individual Ca(2+) nano- and microdomains forming around the mouth of voltage-gated Ca(2+) channels ascertain the tight coupling of fast synaptic vesicle release to membrane depolarization by action potentials. Recent work has established different geometric arrangements of vesicles and Ca(2+) channels at different central synapses and pointed out the role of Ca(2+) syntillas - localized, store operated Ca(2+) signals - in facilitation and spontaneous release. The coupling between Ca(2+) increase and evoked exocytosis is more sluggish in peripheral terminals and neuroendocrine cells, where channels are less clustered and Ca(2+) comes from different sources, including Ca(2+) influx via the plasma membrane and the mobilization of Ca(2+) from intracellular stores. Finally, also non- (electrically) excitable cells display highly localized Ca(2+) signaling domains. We discuss in particular the organization of structural microdomains of Bergmann glia, specialized astrocytes of the cerebellum that have only recently been considered as secretory cells. Glial microdomains are the spatial substrate for functionally segregated Ca(2+) signals upon metabotropic activation. Our review emphasizes the large diversity of different geometric arrangements of vesicles and Ca(2+) sources, leading to a wide spectrum of Ca(2+) signals triggering release.
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Affiliation(s)
- Martin Oheim
- Molecular and Cellular Biophysics of Synaptic Transmission, INSERM, U603, Paris, France.
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Westerink RHS, Rook MB, Beekwilder JP, Wadman WJ. Dual role of calbindin-D28Kin vesicular catecholamine release from mouse chromaffin cells. J Neurochem 2006; 99:628-40. [PMID: 16824046 DOI: 10.1111/j.1471-4159.2006.04099.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
Calbindin-D(28K) is suggested to play a postsynaptic role in neurotransmission and in the regulation of the intracellular Ca(2+) concentration. However, it is still unclear whether calbindin-D(28K) has a role in the regulation of exocytosis, either as Ca(2+) buffer or as Ca(2+) sensor. Amperometric recordings of catecholamine exocytosis from wild-type and calbindin-D(28K) knockout mouse chromaffin cells reveal a strong reduction in the number of released vesicles, as well as in the amount of neurotransmitter released per fusion event in knockout cells. However, Ca(2+) current recordings and Ca(2+) imaging experiments, including video-rate confocal laser scanning microscopy, revealed that the intracellular Ca(2+) dynamics are remarkably similar in wild-type and knockout cells. The combined results demonstrate that calbindin-D(28K) plays an important and dual role in exocytosis, affecting both release frequency and quantal size, apparently without strong effects on intracellular Ca(2+) dynamics. Consequently, the possibility that calbindin-D(28K) functions not only as a Ca(2+) buffer but also as a modulator of vesicular catecholamine release is discussed.
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Affiliation(s)
- R H S Westerink
- Cellular and Molecular Toxicology, Institute for Risk Assessment Sciences, Utrecht University, Utrecht, the Netherlands.
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Marengo FD. Calcium gradients and exocytosis in bovine adrenal chromaffin cells. Cell Calcium 2005; 38:87-99. [PMID: 16076487 DOI: 10.1016/j.ceca.2005.06.006] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2004] [Revised: 05/15/2005] [Accepted: 06/01/2005] [Indexed: 10/25/2022]
Abstract
The relationship between the localized Ca(2+) concentration and depolarization-induced exocytosis was studied in patch-clamped adrenal chromaffin cells using pulsed-laser Ca(2+) imaging and membrane capacitance measurements. Short depolarizing voltage steps induced Ca(2+) gradients and small "synchronous" increases in capacitance during the pulses. Longer pulses increased the capacitance changes, which saturated at 16 fF, suggesting the presence of a small immediately releasable pool of fusion-ready vesicles. A Hill plot of the capacitance changes versus the estimated Ca(2+) concentration in a thin (100 nm) shell beneath the membrane gave n = 2.3 and K(d) = 1.4 microM. Repetitive stimulation elicited a more complex pattern of exocytosis: early pulses induced synchronous capacitance increases, but after five or more pulses there was facilitation of the synchronous responses and gradual increases in capacitance continued between pulses (asynchronous exocytosis) as the steep submembrane Ca(2+) gradients collapsed. Raising the pipette Ca(2+) concentration led to early facilitation of the synchronous response and early appearance of asynchronous exocytosis. We used this data to develop a kinetic model of depolarization-induced exocytosis, where Ca(2+)-dependent fusion of vesicles occurs from a small immediately releasable pool with an affinity of 1-2 microM and vesicles are mobilized to this pool in a Ca(2+)-dependent manner.
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Affiliation(s)
- Fernando D Marengo
- Department of Physiology, UCLA, School of Medicine, Los Angeles, CA 90095, USA.
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