| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
1 Intercollege Graduate Degree Program in Physiology
2 Noll Laboratory, Department of Kinesiology, The Pennsylvania State University, University Park, PA 16802-6900, USA
Reflex-mediated cutaneous vasoconstriction (VC) is impaired in older humans; however, it is unclear whether this blunted VC also occurs during local cooling, which mediates VC through different mechanisms. We tested the hypothesis that the sensitization of cutaneous vessels to noradrenaline (NA) during direct skin cooling seen in young skin is blunted in aged skin. In 11 young (18–30 years) and 11 older (62–76 years) men and women, skin blood flow was monitored at two forearm sites with laser Doppler (LD) flowmetry while local skin temperature was cooled and clamped at 24°C. Cutaneous vascular conductance (CVC; LD flux/mean arterial pressure) was expressed as percentage change from baseline (%
CVCbase). At one site, five doses of NA (10–10–10–2
M) were sequentially infused via intradermal microdialysis during cooling while the other 24°C site served as control (Ringer solution + cooling). At control sites, VC due to cooling alone was similar in young versus older (–54 ± 5 versus
–56 ± 3%
CVCbase, P
= 0.46). In young, NA infusions induced additional dose-dependent VC (10–8, 10–6, 10–4 and 10–2
M: –70 ± 2, –72 ± 3, –78 ± 3 and –79 ± 4%
CVCbase; P < 0.05 versus control). In older subjects, further VC did not occur until the highest infused dose of NA (10–2
M: –70 ± 5%
CVCbase; P < 0.05 versus control). When cutaneous arterioles are sensitized to NA by direct cooling, young skin exhibits the capacity to further constrict to NA in a dose-dependent manner. However, older skin does not display enhanced VC capacity until treated with saturating doses of NA, possibly due to age-associated decrements in Ca2+ availability or 
2C-adrenoceptor function.
(Received 7 December 2004;
accepted after revision 2 February 2005;
first published online 10 February 2005)
Corresponding author C. S. Thompson: The Pennsylvania State University, 119 Noll Laboratory, University Park, PA 16802, USA. Email: cst116{at}psu.edu
This article has been cited by other articles:
|
|
 |
|
  M. W. Ramsey, B. J. Behnke, R. D. Prisby, and M. D. Delp Effects of aging on adipose resistance artery vasoconstriction: possible implications for orthostatic blood pressure regulation J Appl Physiol, November 1, 2007; 103(5): 1636 - 1643. [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]
|
|
|
|
 |
|
 D. W. DeGroot and W. L. Kenney Impaired defense of core temperature in aged humans during mild cold stress Am J Physiol Regulatory Integrative Comp Physiol, January 1, 2007; 292(1): R103 - R108. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
B. G. Helwig, S. Parimi, C. K. Ganta, R. Cober, R. J. Fels, and M. J. Kenney Aging alters regulation of visceral sympathetic nerve responses to acute hypothermia Am J Physiol Regulatory Integrative Comp Physiol, September 1, 2006; 291(3): R573 - R579. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
G. E. Alvarez, K. Zhao, W. A. Kosiba, and J. M. Johnson Relative roles of local and reflex components in cutaneous vasoconstriction during skin cooling in humans J Appl Physiol, June 1, 2006; 100(6): 2083 - 2088. [Abstract] [Full Text] [PDF]
|
|
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
