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AJP - Regulatory, Integrative and Comparative Physiology, Vol 268, Issue 2 324-R333, Copyright © 1995 by American Physiological Society
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R. M. Harper, D. Gozal, G. Aljadeff, J. L. Carroll, X. W. Dong and D. M. Rector
Department of Anatomy and Cell Biology, University of California Los Angeles School of Medicine 90024.
We examined ventral medullary surface activity using light reflectance procedures after blood pressure alterations induced by phenylephrine or sodium nitroprusside in 23 pentobarbital sodium-anesthetized cats. Images of reflected 660-nm light were collected and digitized at 1- to 3-s intervals after baseline and intravenous saline, 5-40 micrograms/kg phenylephrine, or sodium nitroprusside infusion. Carotid sinus nerve denervation (CSD) and bilateral vagotomy were performed in five and three animals, respectively, and challenges were repeated. Phenylephrine elicited a dose-dependent transient blood pressure elevation and reflectance increase (interpreted as activity decline) over the entire ventral medullary surface examined. The increase consisted of an initial rapid transient component, peaking at 45 s, and a 3- to 5-min recovery. CSD enhanced, and vagotomy substantially reduced, the initial transient response to phenylephrine. Sodium nitroprusside-induced lowering of blood pressure was associated with decreased reflectance in rostral sites and increased reflectance in caudal regions. CSD abolished a late component and diminished amplitude of an initial rapidly rising component of changes induced by nitroprusside, a decline further accentuated by addition of vagotomy.
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D. M. Rector, C. A. Richard, R. J. Staba, and R. M. Harper Sleep states alter ventral medullary surface responses to blood pressure challenges Am J Physiol Regulatory Integrative Comp Physiol, April 1, 2000; 278(4): R1090 - R1098. [Abstract] [Full Text] [PDF] |
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C. A. Richard, D. M. Rector, R. K. Harper, and R. M. Harper Optical imaging of the ventral medullary surface across sleep-wake states Am J Physiol Regulatory Integrative Comp Physiol, October 1, 1999; 277(4): R1239 - R1245. [Abstract] [Full Text] [PDF] |
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