|
|
||||||||
Department of Basic and Pharmaceutical Sciences, Albany College of Pharmacy, Albany, New York 12208
Severe hemorrhage lowers arterial pressure by suppressing sympathetic activity. This study tested the hypothesis that the decompensatory phase of hemorrhage is mediated by the ventrolateral periaqueductal gray (vlPAG), a region importantly involved in the autonomic and behavioral responses to stress and trauma. Neuronal activity in the vlPAG was inhibited with either lidocaine or cobalt chloride 5 min before hemorrhage (2.5 ml/100 g body wt) was initiated in conscious, unrestrained rats. Bilateral injection of lidocaine (0.5 µl of a 2% or 1 µl of a 5% solution) into the caudal vlPAG delayed the onset and reduced the magnitude of the hypotension produced by hemorrhage significantly. In contrast, inactivation of the dorsolateral PAG with lidocaine was ineffective. Cobalt chloride (5 mM; 0.5 µl), which inhibits synaptic transmission but not axonal conductance, also attenuated hemorrhagic hypotension significantly. Microinjection of lidocaine or cobalt chloride into the vlPAG of normotensive, nonhemorrhaged rats did not influence cardiovascular function. These data indicate that the vlPAG plays an important role in the response to hemorrhage.
hemorrhage; cardiovascular regulation; lidocaine; cobalt
This article has been cited by other articles:
![]() |
J. Ahlgren, K. Porter, and L. F. Hayward Hemodynamic responses and c-Fos changes associated with hypotensive hemorrhage: standardizing a protocol for severe hemorrhage in conscious rats Am J Physiol Regulatory Integrative Comp Physiol, May 1, 2007; 292(5): R1862 - R1871. [Abstract] [Full Text] [PDF] |
||||
![]() |
M. L. Blair and D. Mickelsen Activation of lateral parabrachial nucleus neurons restores blood pressure and sympathetic vasomotor drive after hypotensive hemorrhage Am J Physiol Regulatory Integrative Comp Physiol, September 1, 2006; 291(3): R742 - R750. [Abstract] [Full Text] [PDF] |
||||
![]() |
J. C. Schadt, H. L. Shafford, and M. D. McKown Neuronal activity within the ventrolateral periaqueductal gray during simulated hemorrhage in conscious rabbits Am J Physiol Regulatory Integrative Comp Physiol, March 1, 2006; 290(3): R715 - R725. [Abstract] [Full Text] [PDF] |
||||
![]() |
J. C. Schadt What is the role of serotonin during hemorrhage in conscious animals? Am J Physiol Regulatory Integrative Comp Physiol, March 1, 2003; 284(3): R780 - R781. [Full Text] [PDF] |
||||
![]() |
K. E. Scrogin 5-HT1A receptor agonist 8-OH-DPAT acts in the hindbrain to reverse the sympatholytic response to severe hemorrhage Am J Physiol Regulatory Integrative Comp Physiol, March 1, 2003; 284(3): R782 - R791. [Abstract] [Full Text] [PDF] |
||||
![]() |
T. E. Lohmeier Neurohumoral regulation of arterial pressure in hemorrhage and heart failure Am J Physiol Regulatory Integrative Comp Physiol, October 1, 2002; 283(4): R810 - R814. [Full Text] [PDF] |
||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| Visit Other APS Journals Online |