ATP-evoked membrane current in guinea pig adrenal chromaffin cells

Otsuguro, Ken-ichi; Asano, Tadashi; Ohta, Toshio; S, Itó; Nakazato, Yoshikazu

doi:10.1016/0304-3940(95)11359-5

Cited by 15 publications

(13 citation statements)

References 19 publications

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“…To our knowledge, this is the first evidence that a voltage-gated ICa is modulated by activation of the Aµ receptor in PC12 cells. It was recently reported that adenosine inhibits Ca¥ currents in guinea-pig adrenal chromaffin cells, but the specific receptor that mediates this response was not identified (Otsuguro, Ohta, Ito & Nakazato, 1996). In PC12 cells, adenosine has been shown to modulate the ATPactivated non-selective cation channels, which are related to the ATP-evoked Ca¥ influx (Inoue, Watano, Koizumi, Nakazawa & Burnstock, 1994).…”

Section: Discussionmentioning

confidence: 99%

Adenosine modulates hypoxia‐induced responses in rat PC12 cells via the A_2A receptor

Kobayashi¹,

Conforti²,

Pun³

et al. 1998

The Journal of Physiology

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The present study was undertaken to determine the role of adenosine in mediating the cellular responses to hypoxia in rat phaeochromocytoma (PC12) cells, an oxygen‐sensitive clonal cell line. Reverse transcriptase polymerase chain reaction studies revealed that PC12 cells express adenosine deaminase (the first catalysing enzyme of adenosine degradation) and the A2A and A2B adenosine receptors, but not the A1 or A3 adenosine receptors. Whole‐cell current‐ and voltage‐clamp experiments showed that adenosine attenuated the hypoxia‐induced membrane depolarization. The hypoxia‐induced suppression of the voltage‐sensitive potassium current (IK(V)) was markedly reduced by adenosine. Furthermore, extracellularly applied adenosine increased the peak amplitudes of IK(V) in a concentration‐dependent manner. This increase was blocked by pretreatment not only with a non‐specific adenosine receptor antagonist, 8‐phenyltheophylline (8‐PT), but also with a selective A2A receptor antagonist, ZM241385. Ca2+ imaging studies using fura‐2 acetoxymethyl ester (fura‐2 AM) revealed that the increase in intracellular free Ca2+ during hypoxic exposure was attenuated significantly by adenosine. Voltage‐clamp studies showed that adenosine inhibited the voltage‐dependent Ca2+ currents (ICa) in a concentration‐dependent fashion. This inhibition was also abolished by both 8‐PT and ZM241385. The modulation of both IK(V) and ICa by adenosine was prevented by intracellular application of an inhibitor of protein kinase A (PKA), PKA inhibitor fragment (6‐22) amide. In addition, the effect of adenosine on either IK(V) or ICa was absent in PKA‐deficient PC12 cells. These results indicate that the modulatory effects of adenosine on the hypoxia‐induced membrane responses of PC12 cells are likely to be mediated via activation of the A2A receptor, and that the PKA pathway is required for these modulatory actions. We propose that this modulation serves to regulate membrane excitability in PC12 cells and possibly other oxygen‐sensitive cells during hypoxia.

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Section: Discussionmentioning

confidence: 99%

Adenosine modulates hypoxia‐induced responses in rat PC12 cells via the A_2A receptor

Kobayashi¹,

Conforti²,

Pun³

et al. 1998

The Journal of Physiology

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“…ATP can produce at least three different effects on adrenal chromaffin cells: inhibition of voltage-gated Ca 2+ channels [113,127,225,311], release of Ca 2+ from internal stores [441] and activation of a nonselective cation channel [402]. While the first two effects are most probably mediated by P2Y receptors, the third effect has the characteristics for the activation of P2X receptors.…”

Section: Adrenal Chromaffin Cellsmentioning

confidence: 99%

“…A biphasic rise in [Ca 2+ ] i was shown in response to extracellular ATP, one phase due to release of Ca 2+ from intracellular sites, the other from extracellular sites which was lost in Ca 2+ -free solutions [347]. This important study was a clear hint for the recognition that both P2X and P2Y receptors are expressed by chromaffin cells [127, 402,441].…”

Section: Adrenal Chromaffin Cellsmentioning

confidence: 99%

Purinergic signalling in endocrine organs

Burnstock

2013

Purinergic Signalling

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There is widespread involvement of purinergic signalling in endocrine biology. Pituitary cells express P1, P2X and P2Y receptor subtypes to mediate hormone release. Adenosine 5′-triphosphate (ATP) regulates insulin release in the pancreas and is involved in the secretion of thyroid hormones. ATP plays a major role in the synthesis, storage and release of catecholamines from the adrenal gland. In the ovary purinoceptors mediate gonadotrophin-induced progesterone secretion, while in the testes, both Sertoli and Leydig cells express purinoceptors that mediate secretion of oestradiol and testosterone, respectively. ATP released as a cotransmitter with noradrenaline is involved in activities of the pineal gland and in the neuroendocrine control of the thymus. In the hypothalamus, ATP and adenosine stimulate or modulate the release of luteinising hormone-releasing hormone, as well as arginine-vasopressin and oxytocin. Functionally active P2X and P2Y receptors have been identified on human placental syncytiotrophoblast cells and on neuroendocrine cells in the lung, skin, prostate and intestine. Adipocytes have been recognised recently to have endocrine function involving purinoceptors.

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confidence: 99%

“…ATP stored in secretory visicles has been shown to be released on exocytosis [5]. ATP has been reported to evoke CA release from adrenal chromaffin cells [1,15] and PC12 cells [13] and to inhibit Ca 2+ currents in adrenal chromaffin cells [3,23].Continuous and on-line assay methods for CA released from cultured adrenal chromaffin cells [11,17] and perfused adrenal glands [4,18] have been developed using an electrochemical detector. We previously reported a simultaneous on-line assay method for CA and ATP released from cultured porcine adrenal chromaffin cells using an electrochemical detector and luciferin-luciferase, respectively [14].…”

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confidence: 99%

Release of Dopamine and ATP from PC12 Cells Treated with Dexamethasone, Reserpine and Bafilomycin A1.

Kasai

Ohta

Nakazato

et al. 2001

The Journal of Veterinary Medical Science

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ABSTRACT. The amounts and time courses of dopamine and ATP released from perfused PC12 cells were examined using a simultaneous on-line recording system. High KCl (60 mM) caused dopamine and ATP release with similar time courses. The relative amount of dopamine to ATP in the effluent was 9.5. In PC12 cells cultured with dexamethasone, reserpine or bafilomycin A1 for 2 days, these drugs did not affect increases of intracellular Ca 2+ in response to high KCl. Dexamethasone doubled the amount of dopamine release induced by high KCl without changing the amount of ATP release. High KCl failed to cause dopamine release in reserpine-treated cells but evoked ATP release. Bafilomycin A1 decreased both high KCl-induced dopamine and ATP release. The ratio of released ATP to total adenine nucleotides and adenosine in response to high KCl was not changed by treatment with the drugs. These results suggest that dopamine and ATP are simultaneously released from secretory vesicles of PC12 cells, in which they are stored via different pathways. Similar to dopamine uptake into secretory vesicles, the H + -gradient across the vesicular membrane developed by vacuolar ATPase may play an important role in the vesicular uptake of ATP. KEY WORDS: ATP, dopamine, on-line, PC12 cell, V-ATPase.J. Vet. Med. Sci. 63(4): 367-372, 2001 It is well known that catecholamine (CA) is stored together with adenosine 5'-triphosphate (ATP) in secretory vesicles of the adrenal medulla [32] and pheochromocytoma (PC12) cells [31]. In adrenal chromaffin cells, it has been reported that CA is present in secretory vesicles but not in the cytosol [24] and that 75% of ATP in the cells is in secretory vesicles [7]. ATP stored in secretory visicles has been shown to be released on exocytosis [5]. ATP has been reported to evoke CA release from adrenal chromaffin cells [1,15] and PC12 cells [13] and to inhibit Ca 2+ currents in adrenal chromaffin cells [3,23].Continuous and on-line assay methods for CA released from cultured adrenal chromaffin cells [11,17] and perfused adrenal glands [4,18] have been developed using an electrochemical detector. We previously reported a simultaneous on-line assay method for CA and ATP released from cultured porcine adrenal chromaffin cells using an electrochemical detector and luciferin-luciferase, respectively [14]. Using this system, we found that CA and ATP appeared in the effluent with similar time courses in response to various secretagogues including high KCl. In the sympathetic nerves of the guinea-pig vas deferens, however, it has been reported that the ratios of CA and ATP appearing in the effluent greatly change during stimulation, suggesting the presence of heterogeneous secretory vesicles with respect to the concentrations of CA and/or ATP [28] and post-release degradation of ATP by soluble ectonucleotidases [29]. Furthermore, the vesicles isolated from PC12 cells have been reported to contain CA and ATP at various concentration ratios (CA/ATP) ranging from 13 to 29 [31].It is well known that ATP and CA are taken up ...

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ATP-evoked membrane current in guinea pig adrenal chromaffin cells

Cited by 15 publications

References 19 publications

Adenosine modulates hypoxia‐induced responses in rat PC12 cells via the A_2A receptor

Adenosine modulates hypoxia‐induced responses in rat PC12 cells via the A_2A receptor

Purinergic signalling in endocrine organs

Release of Dopamine and ATP from PC12 Cells Treated with Dexamethasone, Reserpine and Bafilomycin A1.

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ATP-evoked membrane current in guinea pig adrenal chromaffin cells

Cited by 15 publications

References 19 publications

Adenosine modulates hypoxia‐induced responses in rat PC12 cells via the A2A receptor

Adenosine modulates hypoxia‐induced responses in rat PC12 cells via the A2A receptor

Purinergic signalling in endocrine organs

Release of Dopamine and ATP from PC12 Cells Treated with Dexamethasone, Reserpine and Bafilomycin A1.

Contact Info

Product

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Adenosine modulates hypoxia‐induced responses in rat PC12 cells via the A_2A receptor

Adenosine modulates hypoxia‐induced responses in rat PC12 cells via the A_2A receptor