Characterization of G proteins involved in activation of nonselective cation channels and arachidonic acid release by norepinephrine/{alpha}1A-adrenergic receptors

Yoshifumi Kawanabe,1,2 Nobuo Hashimoto,1 and Tomoh Masaki2

1Departments of Neurosurgery and 2Pharmacology, Kyoto University Graduate School of Medicine, Kyoto 606-8507, Japan

Submitted 25 August 2003 ; accepted in final form 29 October 2003


    ABSTRACT
 TOP
 ABSTRACT
 MATERIAL AND METHODS
 RESULTS
 DISCUSSION
 REFERENCES
 
We demonstrated recently that norepinephrine activates Ca2+-permeable nonselective cation channels (NSCCs) in Chinese hamster ovary cells stably expressing {alpha}1A-adrenergic receptors (CHO-{alpha}1A). Moreover, extracellular Ca2+ through NSCCs plays essential roles in norepinephrine-induced arachidonic acid release. The purpose of the present study was to identify the G proteins involved in the activation of NSCCs and arachidonic acid release by norepinephrine. For these purposes, we used U73122 [GenBank] , an inhibitor of phospholipase C (PLC), and dominant negative mutants of G12 and G13 (G12G228A and G13G225A, respectively). U73122 [GenBank] failed to inhibit NSCCs activation by norepinephrine. The magnitudes of norepinephrine-induced extracellular Ca2+ influx in CHO-{alpha}1A microinjected with G13G225A were smaller than those in CHO-{alpha}1A. In contrast, the magnitudes of norepinephrine-induced extracellular Ca2+ influx in CHO-{alpha}1A microinjected with G12G228A were similar to those in CHO-{alpha}1A. In addition, neither a Rho-associated kinase (ROCK) inhibitor nor a phosphoinositide 3-kinase inhibitor affected norepinephrine-induced extracellular Ca2+ influx. G13G225A, but not G12G228A, also inhibited arachidonic acid release partially. These results demonstrate that 1) the Gq/PLC-pathway is not involved in NSCCs activation by norepinephrine, 2) G13 couples with CHO-{alpha}1A and plays important roles for norepinephrine-induced NSCCs activation, 3) neither ROCK- nor PI3K-dependent cascade is involved in NSCCs activation, and 4) G13 is involved in norepinephrine-induced arachidonic acid release in CHO-{alpha}1A.

norepinephrine; {alpha}1A-adrenergic receptor; nonselective cation channel; G13 protein; arachidonic acid release


{alpha}1-ADRENERGIC RECEPTORS ({alpha}1-ARs) are G protein-coupled receptors and mediate some of the physiological actions of norepinephrine. Several studies have demonstrated that {alpha}1-ARs can activate a variety of effectors including phospholipase C (PLC), phospholipase D, phospholipase A2, cAMP metabolism, and various ion channels (1, 2, 4, 18, 23). Moreover, extracellular Ca2+ influx through nonselective cation channels (NSCCs) plays critical roles for norepinephrine-induced arachidonic acid release and cell proliferation in Chinese hamster ovary cells stably expressing {alpha}1A-ARs (CHO-{alpha}1A) (12, 13). Thus, it is important to elucidate activation mechanisms of NSCCs by norepinephrine. In the present study, we focused on investigating which G protein subtypes were involved in the activation of NSCCs. We have recently shown that a sustained increase in intracellular free Ca2+ concentration ([Ca2+]i) caused by norepinephrine results from Ca2+ entry through NSCCs in CHO-{alpha}1A (12). In particular, NSCCs are sensitive to LOE-908 (5) and resistant to SK&F 96365 (20). {alpha}1-ARs are functionally coupled with Gq in CHO cells (12, 24). However, it remains unclear whether {alpha}1-ARs are coupled with other subtypes of G{alpha} proteins in CHO cells. Dominant negative mutants of G12 and G13 (G12G228A and G13G225A, respectively) inhibit endothelin-1-induced actin stress fiber formation and NSCC activation in CHO cells stably expressing endothelinA receptor and endothelinB receptor (CHO-ETA and CHO-ETB, respectively) (8, 16, 17). Therefore, we used G12G228A and G13G225A to clarify the involvement of G12 and G13 for NSCCs activation by norepinephrine in this study. In addition, we examined the role of G12 and G13 on norepinephrine-induced arachidonic acid release in this study. We demonstrated recently that G12 is involved in endothelin-1-induced arachidonic acid release in CHO-ETA (14).


    MATERIAL AND METHODS
 TOP
 ABSTRACT
 MATERIAL AND METHODS
 RESULTS
 DISCUSSION
 REFERENCES
 
Cell culture. We used CHO-{alpha}1A, which were constructed as described previously (12). Cells were maintained in F-12 medium supplemented with 10% fetal calf serum (FCS) under a humidified 5% CO2-95% air atmosphere.

Measurement of [Ca2+]i. [Ca2+]i was measured using a fluorescent probe fluo 3. The measurements of fluorescence by a CAF 110 spectrophotometer (JASCO, Tokyo, Japan) and an Attofluor Ratio-Vision real time digital fluorescence analyzer (Atto Instruments, Potomac, MD) were performed exactly as described previously (7).

Microinjection of G12G228A and G13G225A. G12G228A and G13G225A in pcDNA 3.1(+) were constructed as described previously (8, 14). Microinjection of G12G228A and G13G225A was performed as described previously (8, 14). Briefly, cells were seeded onto glass coverslips coated with fibronectin (Iwaki Glass, Chiba, Japan), which were marked with a cross to facilitate the localization of injected cells, and incubated overnight in Ham's F-12 medium containing 1% FCS. Plasmids (100 ng/µl) encoding for G12G228A and G13G225A were microinjected into cell nuclei. As a control, expression plasmids without inserts were microinjected in an adjacent field on the same coverslip. Microinjection was performed using a manual microinjection system (Eppendorf-5 Prime, Hamburg, Germany) equipped with an Axiovert 100 inverted microscope (Carl-Zeiss, Frankfurt, Germany).

Transfection of G12G228A and G13G225A. For transient expression of G12G228A or G13G225A, cells were transfected with plasmid (100 ng/µl) encoding for G12G228A or G13G225A by MBS Mammalian Transfection Kit (Stratagene, CA) according to the manufacturer's instructions. After 24 h incubation, we used these cells for measurement of [3H]arachidonic acid release.

[3H]arachidonic acid release. The level of [3H]arachidonic acid release was determined as described previously (12). Briefly, cells in 100-mm dishes were incubated overnight with [3H]arachidonic acid (final concentration, 1 µCi/ml). After washing, norepinephrine was added for 5 min. The medium was then removed, acidified with 100 µl of 1N formic acid, and extracted with 3 ml of chloroform. The extracts were evaporated to dryness, resuspended in 50 µl of chloroform, and applied to silica gel plates for thin-layer chromatography (Merck, Darmstadt, Germany). The plates were developed in heptane/diethyl ether/acetic acid (vol/vol; 75:25:4). The distance of movement was visualized with iodine vapor. The plate was scraped, and the radioactivity was counted with a liquid scintillation counter.

Materials. Constitutively active G12 or G13 in pcDNA3(+) was kindly provided by Dr. Manabu Negishi (Kyoto University, Japan). Welfide (Osaka, Japan) kindly provided Y-27632. Other chemicals were obtained commercially.

Statistical analysis. All results were expressed as means ± SE. The data were subjected to a two-way analysis of variance. When a significant F value was encountered, the Newman-Keuls' multiple range test was used to test for significant differences between treatment groups. A probability level of P < 0.05 was considered statistically significant.


    RESULTS
 TOP
 ABSTRACT
 MATERIAL AND METHODS
 RESULTS
 DISCUSSION
 REFERENCES
 
Effects of U73122 [GenBank] on norepinephrine-induced activation of Ca2+ channels. At first, we examined the involvement of Gq/PLC-dependent pathway in NSCCs activation by norepinephrine based on the data that {alpha}1-ARs are functionally coupled with Gq in CHO cells (13, 24). Norepinephrine at 100 nM induced a biphasic increase in [Ca2+]i consisting of an initial transient peak and a subsequent sustained increase in CHO-{alpha}1A (Fig. 1A). On the other hand, 100 nM norepinephrine induced only a sustained increase in [Ca2+]i in CHO-{alpha}1A treated with 10 µM U73122 [GenBank] , a specific inhibitor of PLC (Fig. 1B). The transient increase in [Ca2+]i was not detected in these cells (Fig. 1, B and C). The magnitudes of sustained increase in [Ca2+]i in U73122 [GenBank] -treated cells were similar to those in control cells (Fig. 1D). The inactive analog of U73122 [GenBank] , U73343 [GenBank] , also failed to inhibit norepinephrine-induced sustained increase in [Ca2+]i (data not shown).



View larger version (27K):
[in this window]
[in a new window]
 
Fig. 1. A and B: original tracings illustrating the effects of U73122 [GenBank] on the norepinephrine-induced increase in intracellular free Ca2+ concentration ([Ca2+]i) in Chinese hamster ovary cells stably expressing {alpha}1A-adrenergic receptors (CHO-{alpha}1A). The cells loaded with fluo 3 were incubated with (B) or without (A) 10 µM U73122 [GenBank] for 10 min before 100 nM norepinephrine stimulation. Norepinephrine was added at the time indicated by the horizontal bar. C and D: effects of U73122 [GenBank] on norepinephrine-induced transient (C) and sustained (D) increase in [Ca2+]i. The transient and sustained increase in [Ca2+]i in CHO-{alpha}1A in the presence of 10 µM U73122 [GenBank] are presented as a percentage of values in its absence. Data are presented as mean ± SE of 10 experiments.

 

Effects of G12G228A and G13G225A on norepinephrine-induced activation of Ca2+ channels. To investigate whether G12 and G13 are involved in the activation of NSCCs, we investigated the effects of G12G228A and G13G225A on the norepinephrine-induced increase in [Ca2+]i in CHO-{alpha}1A. In this experiment, G12G228A and G13G225A were microinjected into CHO-{alpha}1A, and the norepinephrine-induced increase in [Ca2+]i in these cells was analyzed using Attofluor Ratio-Vision real time digital fluorescence analyzer. Norepinephrine at 100 nM induced a biphasic increase in [Ca2+]i consisting of an initial transient peak and a subsequent sustained increase in CHO-{alpha}1A microinjected with G12G228A (Fig. 2A). On the other hand, 100 nM norepinephrine induced only a transient increase in [Ca2+]i in CHO-{alpha}1A microinjected with G13G225A (Fig. 2, B and D). The magnitudes of transient increase in [Ca2+]i in CHO-{alpha}1A microinjected with G13G225A were similar to those in CHO-{alpha}1A and CHO-{alpha}1A microinjected with G12G228A (Fig. 2C). On the other hand, norepinephrine failed to induce a sustained increase in [Ca2+]i in CHO-{alpha}1A microinjected with constitutively active G12 or G13 (data not shown).



View larger version (27K):
[in this window]
[in a new window]
 
Fig. 2. A and B: original tracings illustrating the effects of dominant negative mutant of G12 (G12G228A) and G13 (G13G225A) on the norepinephrine-induced increase in [Ca2+]i in CHO-{alpha}1A. Microinjection of G12G228A or G13G225A and fluo-3 microfluorimetry were performed as described in MATERIALS AND METHODS. C and D: effects of G12G228A and G13G225A on norepinephrine-induced transient (C) and sustained (D) increase in [Ca2+]i. The transient and sustained increase in [Ca2+]i in CHO-{alpha}1A microinjected with G12G228A or G13G225A are presented as a percentage of values in its absence. Data are presented as means ± SE of 10 experiments.

 

Effects of Y-27632 and wortmannin on norepinephrine-induced activation of Ca2+ channels. According to the data using G13G225A, G13 plays important roles in NSCCs activation by norepinephrine. It is generally accepted that Rho/Rho-kinase (ROCK) pathway is a downstream target of G13 (21). We examined the effects of ROCK on norepinephrine-induced increase in [Ca2+]i in CHO-{alpha}1A. In this experiment, Y-27632 was used as a specific inhibitor of ROCK (22). Y-27632 at 10 µM did not affect to the norepinephrine-induced transient and sustained increase in [Ca2+]i (Fig. 3, A-C).



View larger version (34K):
[in this window]
[in a new window]
 
Fig. 3. A: original tracings illustrating the effects of Y-27632 on the norepinephrine-induced increase in [Ca2+]i in CHO-{alpha}1A. The cells loaded with fluo 3 were incubated with 10 µM Y-27632 for 10 min before 100 nM norepinephrine stimulation. Norepinephrine was added at the time indicated by the horizontal bar. B and C: effects of Y-27632 on norepinephrine-induced transient (B) and sustained (C) increase in [Ca2+]i. D: original tracings illustrating the effects of wortmannin on the norepinephrine-induced increase in [Ca2+]i in CHO-{alpha}1A. The cells loaded with fluo 3 were incubated with 1 µM wortmannin for 10 min before 100 nM norepinephrine stimulation. E, F: effects of wortmannin on norepinephrine-induced transient (E) and sustained (F) increase in [Ca2+]i. The transient and sustained increase in [Ca2+]i in CHO-{alpha}1A in the presence of 10 µM Y-27632 is presented as a percentage of values in its absence. Data are presented as means ± SE of 10 experiments.

 

Based on the previous data that phosphoinoditide 3-kinase (PI3K) is involved in some types of NSCCs activation by endothelin-1 in CHO cells stably expressing endothelin receptors (9, 10), we examined the effects of wortmannin, an inhibitor of PI3K, on norepinephrine-induced increase in [Ca2+]i in CHO-{alpha}1A. Wortmannin at 1 µM failed to inhibit the norepinephrine-induced transient and sustained increase in [Ca2+]i (Fig. 3, D-F).

Effects of G12G228A and G13G225A on norepinephrine-induced arachidonic acid release. G12G228A or G13G225A was transiently transfected for evaluating the role of G12 or G13, respectively, in norepinephrine-induced arachidonic acid release. For this purpose, we used MBS Mammalian Transfection Kit. When we transfected green fluorescent protein (GFP) with this method, around 65% of cells were GFP positive (data not shown). The magnitudes of norepinephrine-induced arachidonic acid release in CHO-{alpha}1A transfected with G13G225A were around 20% of those in CHO-{alpha}1A (Fig. 4). In contrast, G12G228A failed to inhibit norepinephrine-induced arachidonic acid release (Fig. 4). The magnitudes of norepinephrine-induced arachidonic acid release in CHO-{alpha}1A transfected with only vector were similar to those in CHO-{alpha}1A (data not shown).



View larger version (19K):
[in this window]
[in a new window]
 
Fig. 4. Effects of G12G228A and G13G225A on norepinephrine-induced arachidonic acid release in CHO-{alpha}1A. Cells were transfected with G12G228A or G13G225A transiently as described in MATERIALS AND METHODS. The cells were incubated with 100 nM norepinephrine for 5 min. Arachidonic acid release was determined as described in MATERIALS AND METHODS. Data presented are means ± SE of 10 experiments. #P < 0.05, significantly different from the control values stimulated by norepinephrine in the absence of G12G228A in each experiment.

 


    DISCUSSION
 TOP
 ABSTRACT
 MATERIAL AND METHODS
 RESULTS
 DISCUSSION
 REFERENCES
 
Norepinephrine at 100 nM evoked an increase in [Ca2+]i consisting of two components: a rapid initial transient peak and a sustained phase (Fig. 1A). The sustained phase was abolished by the removal of extracellular Ca2+, whereas the transient peak remained unaffected (12). These results indicate that the sustained phase is due to a transmembrane Ca2+ influx, whereas the transient phase is the result of Ca2+ mobilization from the intracellular stores as noted previously (6). Extracellular Ca2+ influx through NSCCs plays essential role in norepinephrine-induced cell proliferation and arachidonic acid release in CHO-{alpha}1A (12, 13). Therefore, it is important to reveal the intracellular activation mechanisms of NSCCs by norepinephrine. In this study, we focused on which G proteins were involved in NSCCs activation by norepinephrine in CHO-{alpha}1A. Judging from the data of [3H]inositol phosphate accumulation (12), {alpha}1A-ARs couple with Gq in CHO cells. In addition, it is generally accepted that PLC is activated downstream of Gq (2, 24). Therefore, at first, we examined the involvement of Gq/PLC-pathway in NSCCs activation by norepinephrine. Judging from the data that 1) norepinephrine evokes only sustained increase in [Ca2+]i in U73122 [GenBank] -treated CHO-{alpha}1A (Fig. 1B) and 2) the magnitudes of the sustained increase in [Ca2+]i in U73122 [GenBank] -treated CHO-{alpha}1A were similar to those in control CHO-{alpha}1A (Fig. 1D), the Gq/PLC-pathway plays an important role in norepinephrine-induced Ca2+ release from the intracellular stores, whereas activation of NSCCs is independent of the Gq/PLC-pathway. Because G12 and G13 are involved in NSCCs activation by endothelin-1 in CHO cells stably expressing endothelin receptors (8, 16) and C6 glioma cells (11), we examined the effects of G12 and G13 on NSCCs activation by norepinephrine using G12G228A and G13G225A. Based on the data that 1) the magnitudes of the transient increase in [Ca2+]i in CHO-{alpha}1A microinjected with G12G228A or G13G225A were similar to those in the control CHO-{alpha}1A (Fig. 2), 2) norepinephrine failed to induce a sustained increase in [Ca2+]i in CHO-{alpha}1A microinjected with G13G225A (Fig. 2, B and D), and 3) the magnitudes of the sustained increase in [Ca2+]i in CHO-{alpha}1A microinjected with G12G228A were similar to those in the control CHO-{alpha}1A (Fig. 2, A and D), {alpha}1A-ARs may couple with G13, but not with G12, in CHO cells, and the G13-dependent pathway plays an important role for activation of NSCCs, whereas norepinephrine-induced mobilization of Ca2+ from the intracellular Ca2+ store may not be involved. Based on the data using constitutively active G12 or G13, NSCCs have already been activated before adding norepinephrine. These data may support that {alpha}1A-ARs may couple with G13, but not with G12, in CHO cells. A previous report demonstrates that G12/G13 mediates {alpha}1-AR-induced cardiac hypertrophy (19). It is interesting that the {alpha}1-AR may be capable of coupling to different G proteins in different cell types. Because the Rho/ROCK pathway is a downstream target of G13 (21), we investigated the effects of ROCK on the activation of NSCCs by norepinephrine using Y-27632. Based on the lack of sensitivity to Y-27632, G13 activates NSCCs via ROCK-independent signaling pathways. Further study is needed to identify the regulators downstream of G13 for activation of NSCCs. PI3K is involved in some types of NSCCs activation by endothelin-1 in CHO cells stably expressing endothelin receptors (9, 10). However, PI3K is not involved in NSCCs activation by norepinephrine in CHO-{alpha}1A judging from the lack of sensitivity to wortmannin (Fig. 3).

Extracellular Ca2+ influx through NSCCs plays a critical role for norepinephrine-induced arachidonic acid release in CHO-{alpha}1A (12). Therefore, we examined the effects of G13 on norepinephrine-induced arachidonic acid release. Disruption of signaling through endogenous G13 by its dominant negative mutant (G13G225A) inhibited norepinephrine-induced arachidonic acid release in CHO-{alpha}1A (Fig. 4), indicating that activation of arachidonic acid release is mediated by G13. In contrast, G12G228A failed to inhibit norepinephrine-induced arachidonic acid release (Fig. 4). Therefore, G13, but not G12, plays important roles in norepinephrine-induced arachidonic acid release. Norepinephrine-induced arachidonic acid release was not inhibited completely by G13G225A in this study (Fig. 4). We think that this is because G13G225A is not transfected to all cells. However, another possibility is that norepinephrine induces arachidonic acid release with another unknown pathway in CHO-{alpha}1A. Further research is necessary to confirm this.

Next, we summarized the pharmacological characteristics and activation mechanisms of Ca2+ channels activated by norepinephrine in CHO-{alpha}1A and by endothelin-1 in CHO-ETA and CHO-ETB (Table 1). On the basis of the sensitivity to Ca2+ channel blockers, SK&F 96365 and LOE 908, NSCCs activated by norepinephrine in CHO-{alpha}1A (11) and NSCC-1 activated by endothelin-1 in CHO-ETA and CHO-ETB (15) have the same pharmacological sensitivities (LOE 908-sensitivity and SK&F 96365-resistance). In addition, the activation mechanisms of NSCCs by norepinephrine in CHO-{alpha}1A (Fig. 2) are similar to those of NSCC-1 in CHO-ETB (8) at the following points. 1) Both channels are activated via G13-dependent and Gq/PLC-independent pathways. 2) Neither Rocknor PI3K-dependent pathway are involved in these channels' activation. These results indicate that {alpha}1A-ARs and endothelinB receptors may activate some types of NSCCs (NSCC-1) via the same pathways in CHO cells. Moreover, NSCCs activated by norepinephrine are included in NSCC-1.


View this table:
[in this window]
[in a new window]
 
Table 1. Summary of Ca2+ channels activated by norepinephrine receptors or endothelin-1 receptors in Chinese hamster ovary cells

 


    ACKNOWLEDGMENTS
 
We thank Welfide for the kind donation of Y-27632. We also thank Drs. Makoto Taketo, Masanobu Oshima, and Tomo-o Ishikawa (Department of Pharmacology, Kyoto University Graduate School of Medicine, Kyoto, Japan) for technical support.

GRANTS

This study was supported by a grant from the Smoking Research Foundation, Japan, and by the Uehara Memorial Foundation Fellowship, Tokyo, Japan.


    FOOTNOTES
 

Address for reprint requests and other correspondence: Y. Kawanabe, Renal Division, Dept. of Medicine, Brigham and Women's Hospital and Harvard Medical School, Harvard Institute of Medicine, Rm. 520, 77 Ave. Louis Pasteur, Boston, MA 02115 (E-mail; ykawanabe{at}rics.bwh.harvard.edu).

The costs of publication of this article were defrayed in part by the payment of page charges. The article must therefore be hereby marked "advertisement" in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.


    REFERENCES
 TOP
 ABSTRACT
 MATERIAL AND METHODS
 RESULTS
 DISCUSSION
 REFERENCES
 
1. Apkon M and Nerbonne JM. Alpha 1-adrenergic agonists selectively suppress voltage-dependent K+ current in rat ventricular myocytes. Proc Natl Acad Sci USA 85: 8756-8760, 1988.[Abstract]

2. Berridge MJ. Inositol triphosphate and calcium signalling. Nature 361: 315-325, 1993.[CrossRef][ISI][Medline]

3. Burch RM, Luini A, Mais DE, Corda D, Vanderhoek JY, Kohn LD, and Axelrod J. Alpha 1-adrenergic stimulation of arachidonic acid release and metabolism in a rat thyroid cell line. Mediation of cell replication by prostaglandin E2. J Biol Chem 261: 11236-11241, 1986.[Abstract/Free Full Text]

4. Davis JN, Arnett CD, Hoyler E, Stalvey LP, Daly JW, and Skolnick P. Brain alpha-adrenergic receptors: comparison of [3H]WB 4101 binding with noradrenaline-stimulated cyclic AMP accumulation in rat cerebral cortex. Brain Res 159: 125-135, 1978.[CrossRef][ISI][Medline]

5. Encabo A, Romanin C, Birke FW, Kukovetz WR, and Groschner K. Inhibition of a store-operated Ca2+ entry pathway in human endothelial cells by the isoquinoline derivative LOE 908. Br J Pharmacol 119: 702-706, 1996.[Abstract]

6. Gardner P. Calcium and T lymphocyte activation. Cell 59: 15-20, 1989.[ISI][Medline]

7. Kawanabe Y, Hashimoto N, and Masaki T. Ca2+ channels involved in endothelin-induced mitogenic response in carotid artery vascular smooth muscle cells. Am J Physiol Cell Physiol 282: C330-C337, 2002.[Abstract/Free Full Text]

8. Kawanabe Y, Hashimoto N, and Masaki T. Characterization of G proteins involved in activation of nonselective cation channels by endothelinB receptor. Br J Pharmacol 136: 1015-1022, 2002.[Abstract/Free Full Text]

9. Kawanabe Y, Hashimoto N, and Masaki T. Effects of phosphoinositide 3-kinase on the endothelin-1-induced activation of voltage-independent Ca2+ channels and mitogenesis in Chinese hamster ovary cells stably expressing endothelinA receptor. Mol Pharmacol 62: 756-761, 2002.[Abstract/Free Full Text]

10. Kawanabe Y, Hashimoto N, and Masaki T. Role of phosphoinositide 3-kinase in the nonselective cation channel activation by endothelin-1/endothelinB receptor. Am J Physiol Cell Physiol 284: C506-C510, 2003.[Abstract/Free Full Text]

11. Kawanabe Y, Hashimoto N, and Masaki T. Molecular mechanisms for activation of Ca2+-permeable nonselective cation channels by endothelin-1 in C6 glioma cells. Biochem Pharmacol 65: 1435-1439, 2003.[CrossRef][ISI][Medline]

12. Kawanabe Y, Hashimoto N, Masaki T, and Miwa S. Ca2+ influx through nonselective cation channels plays an essential role in noradrenaline-induced arachidonic acid release in Chinese hamster ovary cells expressing {alpha}1A-, {alpha}1B-, or {alpha}1D-adrenergic receptors. J Pharmacol Exp Ther 299: 901-907, 2001.[Abstract/Free Full Text]

13. Kawanabe Y, Hashimoto N, Miwa S, and Masaki T. Effects of Ca2+ influx through nonselective cation channel on noradrenaline-induced mitogenic responses. Eur J Pharmacol 447: 31-36, 2002.[CrossRef][ISI][Medline]

14. Kawanabe Y, Nozaki K, Hashimoto N, and Masaki T. Characterization of Ca2+ channels and G proteins involved in arachidonic acid release by endothelin-1/endothelinA receptor. Mol Pharmacol 64: 689-695, 2003.[Abstract/Free Full Text]

15. Kawanabe Y, Okamoto Y, Enoki T, Hashimoto N, and Masaki T. Ca2+ channels activated by endothelin-1 in CHO cells expressing endothelin-A or endothelin-B receptors. Am J Physiol Cell Physiol 281: C1676-C1685, 2001.[Abstract/Free Full Text]

16. Kawanabe Y, Okamoto Y, Miwa S, Hashimoto N, and Masaki T. Molecular mechanisms for the activation of voltage-independent Ca2+ channels by endothelin-1 in Chinese hamster ovary cells stably expressing human endothelinA receptors. Mol Pharmacol 62: 75-80, 2002.[Abstract/Free Full Text]

17. Kawanabe Y, Okamoto Y, Nozaki K, Hashimoto N, Miwa S, and Masaki T. Molecular mechanism for endothelin-1-induced stress-fiber formation: analysis of G proteins using a mutant endothelinA receptor. Mol Pharmacol 61: 277-284, 2002.[Abstract/Free Full Text]

18. Llahi S and Fain JN. Alpha1-adrenergic receptor-mediated activation of phospholipase D in rat cerebral cortex. J Biol Chem 267: 3679-3685, 1992.[Abstract/Free Full Text]

19. Maruyama Y, Nishida M, Sugimoto Y, Tanabe S, Turner JH, Kozasa T, Wada T, Nagao T, and Kurose H. Galpha12/13 mediates alpha1-adrenergic receptor-induced cardiac hypertrophy. Circ Res 91: 961-969, 2002.[Abstract/Free Full Text]

20. Meritt JE, Airmstrong WP, Benham CD, Hallam TJ, Jacob R, Jaxa-Chamiec A, Leigh BK, Mccarthy SA, Moores KE, and Rink TJ. SK&F 96365, a novel inhibitor of receptor-mediated calcium entry. Biochem J 271: 515-522, 1990.[ISI][Medline]

21. Seasholtz TM, Majumdar M, and Brown JH. Rho as a mediator of G protein-coupled receptor signaling. Mol Pharmacol 55: 949-956, 1999.[Free Full Text]

22. Uehata M, Ishizaki T, Satoh H, Ono T, Kawahara T, Morishima T, Tamakawa H, Yamagami K, Inui J, Maekawa M, and Narumiya S. Calcium sensitization of smooth muscle mediated by a Rho-associated protein kinase in hypertension. Nature 389: 990-994, 1997.[CrossRef][ISI][Medline]

23. Wilson KM and Minneman KP. Different pathways of [3H]inositol phosphate formation mediated by alpha1a- and alpha1b-adrenergic receptors. J Biol Chem 265: 17601-17606, 1990.[Abstract/Free Full Text]

24. Wu D, Katz A, Lee CH, and Simon MI. Activation of phospholipase C by alpha1-adrenergic receptors is mediated by the alpha subunits of Gq family. J Biol Chem 267: 25798-25802, 1992.[Abstract/Free Full Text]





This Article
Abstract
Full Text (PDF)
Alert me when this article is cited
Alert me if a correction is posted
Citation Map
Services
Email this article to a friend
Similar articles in this journal
Similar articles in ISI Web of Science
Similar articles in PubMed
Alert me to new issues of the journal
Download to citation manager
Search for citing articles in:
ISI Web of Science (2)
Google Scholar
Articles by Kawanabe, Y.
Articles by Masaki, T.
Articles citing this Article
PubMed
PubMed Citation
Articles by Kawanabe, Y.
Articles by Masaki, T.


HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
Visit Other APS Journals Online
Copyright © 2004 by the American Physiological Society.