| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
1 Clinical Research Department
and Second Institute of Physiology,
We studied whether vasoactive drugs used to determine baroreflex sensitivity influence baroreceptor firing by affecting carotid sinus smooth muscle or simply by stretching the sinus wall through changes in pressure. In six young healthy subjects, the diameter of the carotid artery and its change with arterial pulse were measured with ultrasonography. Blood pressure was measured by Finapres. Phenylephrine and nitroglycerin doses were injected intravenously to raise and lower pressure by ~15-25 mmHg. Carotid dimensions increased in all subjects during the phenylephrine-induced rise and decreased during the nitroglycerin-induced fall in pressure. Diastolic diameter changed more than systolic diameter; changes were significantly different from the control value (assessed by single-factor analysis of variance and Scheffé's post hoc test). The systolic pressure-diameter relationship appeared to be nonlinear, with a steeper slope above than below baseline, and contributed significantly to the nonlinearity of the R-R interval-systolic pressure relationship. It is concluded that during drug-induced changes in blood pressure, baroreceptor activity in humans is influenced more by passive stretch than by local smooth muscle contraction.
echo tracking; baroreflex sensitivity; carotid distensibility; phenylephrine; nitroglycerin
This article has been cited by other articles:
|
|
 |
|
  C. N. Young, J. P. Fisher, and P. J. Fadel The ups and downs of assessing baroreflex function J. Physiol., March 1, 2008; 586(5): 1209 - 1211. [Full Text] [PDF]
|
|
|
|
|
|
P. Studinger, R. Goldstein, and J. A. Taylor Mechanical and neural contributions to hysteresis in the cardiac vagal limb of the arterial baroreflex J. Physiol., September 15, 2007; 583(3): 1041 - 1048. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 C. W. Myers, W. B. Farquhar, D. E. Forman, T. D. Williams, D. L. Dierks, and J. A. Taylor Carotid distensibility characterized via the isometric exercise pressor response Am J Physiol Heart Circ Physiol, December 1, 2002; 283(6): H2592 - H2598. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 K. D. Monahan, H. Tanaka, F. A. Dinenno, and D. R. Seals Central Arterial Compliance Is Associated With Age- and Habitual Exercise-Related Differences in Cardiovagal Baroreflex Sensitivity Circulation, October 2, 2001; 104(14): 1627 - 1632. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 S. Chowdhary, J. C. Vaile, J. Fletcher, H. F. Ross, J. H. Coote, and J. N. Townend Nitric Oxide and Cardiac Autonomic Control in Humans Hypertension, August 1, 2000; 36(2): 264 - 269. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
N. Hogan, A. Kardos, D. J. Paterson, and B. Casadei Effect of exogenous nitric oxide on baroreflex function in humans Am J Physiol Heart Circ Physiol, July 1, 1999; 277(1): H221 - H227. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
L. Rudas, A. A. Crossman, C. A. Morillo, J. R. Halliwill, K. U. O. Tahvanainen, T. A. Kuusela, and D. L. Eckberg Human sympathetic and vagal baroreflex responses to sequential nitroprusside and phenylephrine Am J Physiol Heart Circ Physiol, May 1, 1999; 276(5): H1691 - H1698. [Abstract] [Full Text] [PDF]
|
|
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| Visit Other APS Journals Online |
