| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
CARDIOVASCULAR |
1 Department of Physiology, University of Texas Health Science Center, San Antonio, TX 78229, USA
Cutaneous vascular conductance (CVC) declines in response to local cooling (LC). Previous work indicates that at least part of the vasoconstrictor response to LC may be through an inhibitory effect on nitric oxide synthase (NOS) activity. In this study we further tested that notion. A total of eight (6 male, 2 female) subjects participated (Part 1 n = 7; Part 2 n = 5, 4 of whom participated in Part 1). Skin blood flow was monitored by laser-Doppler flowmetry. Control of local skin and body temperatures was achieved with Peltier cooler/heater probe holders and water perfused suits, respectively. Microdialysis fibres were inserted aseptically. Saline, L-NAME (20 mM; to inhibit NOS activity) and sodium nitroprusside (SNP 10 µM) were infused by microdialysis. Bretylium tosylate (BT), to block adrenergic function, was administered by iontophoresis. CVC was calculated from blood flow and blood pressure. Part 1 was designed to determine the relative roles of the NO and the adrenergic systems. The infusion of L-NAME elicited a 35 ± 4% decrease in CVC at the L-NAME and BT + L-NAME sites (P < 0.05); subsequent slow LC (34–24°C) for 35 min caused a significant (P < 0.05) decrease in CVC at control sites (68 ± 4%) and at the BT treated sites (39 ± 5%). LC caused a further 23 ± 5% of initial baseline decrease in CVC at the L-NAME treated sites (P < 0.05). Importantly, CVC at the BT + L-NAME sites was unaffected by LC (P > 0.05). Part 2 was designed to test whether LC influences were specific to the NOS enzymes. Two sites were pretreated with both BT and L-NAME. After 50 min, SNP was added as an NO donor to restore baseline CVC at one site. The same LC process as in Part 1 was applied. There was a 24 ± 10% decrease (P < 0.05) in CVC at sites with baseline CVC restored, while, as in Part 1, there was no change (P > 0.05) at sites treated with BT + L-NAME only. These data suggest that the vasoconstriction with slow LC is due to a combination of increased noradrenaline release and decreased activity of both NOS per se and of process(es) downstream of NOS.
(Received 16 March 2006;
accepted after revision 21 May 2006;
first published online 25 May 2006)
Corresponding author J. M. Johnson: Department of Physiology–MSC 7756, 7703 Floyd Curl Drive, San Antonio, TX 78229-3900, USA. Email: johnson{at}uthscsa.edu
This article has been cited by other articles:
|
|
 |
|
  V. Vuksanovic, L. W. Sheppard, and A. Stefanovska Nonlinear Relationship between Level of Blood Flow and Skin Temperature for Different Dynamics of Temperature Change Biophys. J., May 15, 2008; 94(10): L78 - L80. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 S. Schmidt, R. Banks, V. Kumar, K. H. Rand, and H. Derendorf Clinical Microdialysis in Skin and Soft Tissues: An Update J. Clin. Pharmacol., March 1, 2008; 48(3): 351 - 364. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 G. J. Hodges, W. A. Kosiba, K. Zhao, G. E. Alvarez, and J. M. Johnson The role of baseline in the cutaneous vasoconstrictor responses during combined local and whole body cooling in humans Am J Physiol Heart Circ Physiol, November 1, 2007; 293(5): H3187 - H3192. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 G. H. Simmons, C. T. Minson, J.-L. Cracowski, and J. R. Halliwill Systemic hypoxia causes cutaneous vasodilation in healthy humans J Appl Physiol, August 1, 2007; 103(2): 608 - 615. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
C. S. Thompson-Torgerson, L. A. Holowatz, N. A. Flavahan, and W. Larry Kenney Rho kinase-mediated local cold-induced cutaneous vasoconstriction is augmented in aged human skin Am J Physiol Heart Circ Physiol, July 1, 2007; 293(1): H30 - H36. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
G. J. Hodges, J. A. Traeger III, T. Tang, W. A. Kosiba, K. Zhao, and J. M. Johnson Role of sensory nerves in the cutaneous vasoconstrictor response to local cooling in humans Am J Physiol Heart Circ Physiol, July 1, 2007; 293(1): H784 - H789. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
C. S. Thompson-Torgerson, L. A. Holowatz, N. A. Flavahan, and W. L. Kenney Cold-induced cutaneous vasoconstriction is mediated by Rho kinase in vivo in human skin Am J Physiol Heart Circ Physiol, April 1, 2007; 292(4): H1700 - H1705. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. M. Johnson Mechanisms of vasoconstriction with direct skin cooling in humans Am J Physiol Heart Circ Physiol, April 1, 2007; 292(4): H1690 - H1691. [Full Text] [PDF]
|
|
|
|
 |
|
 L. A. Sokolnicki, S. K. Roberts, B. W. Wilkins, A. Basu, and N. Charkoudian Contribution of nitric oxide to cutaneous microvascular dilation in individuals with type 2 diabetes mellitus Am J Physiol Endocrinol Metab, January 1, 2007; 292(1): E314 - E318. [Abstract] [Full Text] [PDF]
|
|
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
