| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
1 Department of Anesthesiology, Baylor College of Medicine, Houston, Texas 77030; and 2 Department of Internal Medicine, Lund University Hospital, Lund, S-221 85 Sweden
The effects of stimulating
P2Y1 or
P2Y2 purinoceptors on the
endothelium of isolated middle cerebral arteries (MCAs), third-order branches of the MCA (bMCAs), and penetrating arterioles (PAs) of the
rat were studied. After pressurization and development of spontaneous
tone (25% contraction), resting diameters for MCAs, bMCAs, and PAs
were 203 ± 5 (n = 50), 99 ± 2 (n = 42), and 87 ± 2 µm
(n = 53), respectively. Luminal
application of the P2Y1-selective agonist 2-methylthioadenosine 5'-triphosphate elicited
dose-dependent dilations (or loss of intrinsic tone) in MCAs but not in
bMCAs or PAs. The dilation in MCAs was completely blocked by removal of
the endothelium or by nitro-L-arginine methyl ester
(10
5 M), an inhibitor of NO
synthase. Luminal application of the
P2Y2-selective agonist ATP
elicited dilations in MCAs, bMCAs, and PAs. Removal of the endothelium
abolished the dilations in all vessel groups. Dilations in MCAs have
been shown to involve both NO and endothelium-derived hyperpolarizing
factor (EDHF). The dilations in bMCAs and PAs had a minor NO component
and prominent EDHF component; that is, 1) the dilations to ATP were not
diminished by the combined inhibition of NO synthase and
cyclooxygenase, 2) the dilations
were accompanied by significant hyperpolarizations of the vascular
smooth muscle (~15 mV), and 3) the
dilations were completely abolished by the calcium-activated potassium
channel blocker charybdotoxin. We concluded that the role of NO in
purinoceptor-induced dilations diminishes along the cerebrovascular
tree in the rat, whereas the role of EDHF becomes more prominent.
calcium-activated potassium channels; endothelium; vascular smooth muscle; P2Y2- and P2Y1-purinoceptor subtypes; nitric oxide; endothelium-derived hyperpolarizing factor
This article has been cited by other articles:
|
|
 |
|
  J. Andresen, N. I. Shafi, and R. M. Bryan Jr. Endothelial influences on cerebrovascular tone J Appl Physiol, January 1, 2006; 100(1): 318 - 327. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 J. You, E. M. Golding, and R. M. Bryan Jr. Arachidonic acid metabolites, hydrogen peroxide, and EDHF in cerebral arteries Am J Physiol Heart Circ Physiol, September 1, 2005; 289(3): H1077 - H1083. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
F. M. Faraci, C. Lynch, and K. G. Lamping Responses of cerebral arterioles to ADP: eNOS-dependent and eNOS-independent mechanisms Am J Physiol Heart Circ Physiol, December 1, 2004; 287(6): H2871 - H2876. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
G. G. Konduri, I. Bakhutashvili, R. Frenn, I. Chandrasekhar, E. R. Jacobs, and A. K. Khanna P2Y purine receptor responses and expression in the pulmonary circulation of juvenile rabbits Am J Physiol Heart Circ Physiol, July 1, 2004; 287(1): H157 - H164. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
Y. Miyagi and J. H. Zhang {alpha},{beta}-Methylene ATP enhances P2Y4 contraction of rabbit basilar artery Am J Physiol Heart Circ Physiol, April 1, 2004; 286(4): H1546 - H1551. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
R. J. Gonzales, D. N. Krause, and S. P. Duckles Testosterone suppresses endothelium-dependent dilation of rat middle cerebral arteries Am J Physiol Heart Circ Physiol, February 1, 2004; 286(2): H552 - H560. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. A. Ospina, S. P. Duckles, and D. N. Krause 17{beta}-Estradiol decreases vascular tone in cerebral arteries by shifting COX-dependent vasoconstriction to vasodilation Am J Physiol Heart Circ Physiol, June 5, 2003; 285(1): H241 - H250. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 E. M. Golding, S. P. Marrelli, J. You, and R. M. Bryan Jr Endothelium-Derived Hyperpolarizing Factor in the Brain: A New Regulator of Cerebral Blood Flow? Stroke, March 1, 2002; 33(3): 661 - 663. [Full Text] [PDF]
|
|
|
|
|
|
L. A. Schildmeyer and R. M. Bryan Jr. Effect of NO on EDHF response in rat middle cerebral arteries Am J Physiol Heart Circ Physiol, February 1, 2002; 282(2): H734 - H738. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
H. L. Xu, R. A. Santizo, H. M. Koenig, and D. A. Pelligrino Chronic estrogen depletion alters adenosine diphosphate-induced pial arteriolar dilation in female rats Am J Physiol Heart Circ Physiol, November 1, 2001; 281(5): H2105 - H2112. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
E. M. Golding and T. E. Kepler Role of estrogen in modulating EDHF-mediated dilations in the female rat middle cerebral artery Am J Physiol Heart Circ Physiol, June 1, 2001; 280(6): H2417 - H2423. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
R. M. Bryan Jr., S. P. Marrelli, M. L. Steenberg, L. A. Schildmeyer, and T. D. Johnson Effects of luminal shear stress on cerebral arteries and arterioles Am J Physiol Heart Circ Physiol, May 1, 2001; 280(5): H2011 - H2022. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
A. C. Ngai, E. F. Coyne, J. R. Meno, G. A. West, and H. R. Winn Receptor subtypes mediating adenosine-induced dilation of cerebral arterioles Am J Physiol Heart Circ Physiol, May 1, 2001; 280(5): H2329 - H2335. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
T. Horiuchi, H. H. Dietrich, S. Tsugane, and R. G. Dacey Jr. Analysis of purine- and pyrimidine-induced vascular responses in the isolated rat cerebral arteriole Am J Physiol Heart Circ Physiol, February 1, 2001; 280(2): H767 - H776. [Abstract] [Full Text] [PDF]
|
|
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| Visit Other APS Journals Online |
