| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
1 Louisiana State University School of Medicine; and 2 Department of Physiology, Tulane University School of Medicine, New Orleans, Louisiana 70112
This study tested the hypothesis
that P2X receptor activation increases intracellular Ca2+
concentration ([Ca2+]i) in preglomerular
microvascular smooth muscle cells (MVSMC) by evoking voltage-dependent
calcium influx. MVSMC were obtained and loaded with the
calcium-sensitive dye fura 2 and studied by using single-cell
fluorescence microscopy. The effect of P2X receptor activation on
[Ca2+]i was assessed by using the P2X
receptor-selective agonist 
,
-methylene-ATP and was compared with
responses elicited by the endogenous P2 receptor agonist ATP.
,-Methylene-ATP increased [Ca2+]i dose
dependently. Peak increases in [Ca2+]i
averaged 37 ± 11, 73 ± 15, and 103 ± 21 nM at agonist
concentrations of 0.1, 1, and 10 µM, respectively. The average peak
response elicited by 10 µM ,-methylene-ATP was ~34% of the
response obtained with 10 µM ATP. ,-Methylene-ATP induced a
transient increase in [Ca2+]i before
[Ca2+]i returned to baseline, whereas ATP
induced a biphasic response including a peak response followed by a
sustained plateau. In Ca2+-free medium, ATP induced a sharp
transient increase in [Ca2+]i, whereas the
response to ,-methylene-ATP was abolished. Ca2+
channel blockade with 10 µM diltiazem or nifedipine attenuated the
response to ,-methylene-ATP, whereas nonspecific blockade of
Ca2+ influx pathways with 5 mM Ni2+ abolished
the response. Blockade of P2X receptors with the novel P2X
receptor antagonist NF-279 completely but reversibly
abolished the response to ,-methylene-ATP. These results
indicate that P2X receptor activation by ,-methylene-ATP
increases [Ca2+]i in preglomerular MVSMC, in
part, by stimulating voltage-dependent Ca2+ influx through
L-type Ca2+ channels.
microvascular smooth muscle cells; adeonsine 5'-triphosphate; afferent arteriole; renal microvasculature; 8,8'-[carbonylbis(imino-4,1-phenylenecarbonylimino-4,1-phenylenecarbonylimino)]bis-1,3,5-napthalenetrisulfonic
acid hexasodium salt; ,-methylene-adeonsine 5'-triphosphate; nifedipine; diltiazem; nickel; calcium channels; P2X receptors
This article has been cited by other articles:
|
|
 |
|
  I. Rivera, S. Zhang, B. S. Fuller, B. Edwards, T. Seki, M.-H. Wang, M. B. Marrero, and E. W. Inscho P2 receptor regulation of [Ca2+]i in cultured mouse mesangial cells Am J Physiol Renal Physiol, May 1, 2007; 292(5): F1380 - F1389. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. P. Schneider, E. W. Inscho, and D. M. Pollock Attenuated vasoconstrictor responses to endothelin in afferent arterioles during a high-salt diet Am J Physiol Renal Physiol, April 1, 2007; 292(4): F1208 - F1214. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
T. Takenaka, H. Okada, Y. Kanno, T. Inoue, M. Ryuzaki, H. Nakamoto, H. Kawachi, F. Shimizu, and H. Suzuki Exogenous 5'-nucleotidase improves glomerular autoregulation in Thy-1 nephritic rats Am J Physiol Renal Physiol, April 1, 2006; 290(4): F844 - F853. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 A. Nishiyama, K. E. Jackson, D. S. A. Majid, M. Rahman, and L. G. Navar Renal interstitial fluid ATP responses to arterial pressure and tubuloglomerular feedback activation during calcium channel blockade Am J Physiol Heart Circ Physiol, February 1, 2006; 290(2): H772 - H777. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 X. Zhao, A. K. Cook, M. Field, B. Edwards, S. Zhang, Z. Zhang, J. S. Pollock, J. D. Imig, and E. W. Inscho Impaired Ca2+ Signaling Attenuates P2X Receptor-Mediated Vasoconstriction of Afferent Arterioles in Angiotensin II Hypertension Hypertension, September 1, 2005; 46(3): 562 - 568. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 X. Zhao, J. R. Falck, V. R. Gopal, E. W. Inscho, and J. D. Imig P2X Receptor-Stimulated Calcium Responses in Preglomerular Vascular Smooth Muscle Cells Involves 20-Hydroxyeicosatetraenoic Acid J. Pharmacol. Exp. Ther., December 1, 2004; 311(3): 1211 - 1217. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 Y. Koura, A. Ichihara, Y. Tada, Y. Kaneshiro, H. Okada, C. J. Temm, M. Hayashi, and T. Saruta Anandamide Decreases Glomerular Filtration Rate through Predominant Vasodilation of Efferent Arterioles in Rat Kidneys J. Am. Soc. Nephrol., June 1, 2004; 15(6): 1488 - 1494. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 M.-L. He, H. Zemkova, T.-a. Koshimizu, M. Tomic, and S. S. Stojilkovic Intracellular calcium measurements as a method in studies on activity of purinergic P2X receptor channels Am J Physiol Cell Physiol, August 1, 2003; 285(2): C467 - C479. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 R. A. North Molecular Physiology of P2X Receptors Physiol Rev, October 1, 2002; 82(4): 1013 - 1067. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
X. Zhao, E. W. Inscho, M. Bondlela, J. R. Falck, and J. D. Imig The CYP450 hydroxylase pathway contributes to P2X receptor-mediated afferent arteriolar vasoconstriction Am J Physiol Heart Circ Physiol, November 1, 2001; 281(5): H2089 - H2096. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
E. W. Inscho P2 receptors in regulation of renal microvascular function Am J Physiol Renal Physiol, June 1, 2001; 280(6): F927 - F944. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
E. W. Inscho and A. K. Cook P2 receptor-mediated afferent arteriolar vasoconstriction during calcium blockade Am J Physiol Renal Physiol, February 1, 2002; 282(2): F245 - F255. [Abstract] [Full Text] [PDF]
|
|
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| Visit Other APS Journals Online |
