Imaging of VMS activity during blood pressure challenges in awake and anesthetized goats. Am J Physiol 1996 Jan;270(1 Pt 2):R182-91
Date
01/01/1996Pubmed ID
8769801DOI
10.1152/ajpregu.1996.270.1.R182Scopus ID
2-s2.0-0030058267 (requires institutional sign-in at Scopus site) 21 CitationsAbstract
We examined scattered-light changes in a rostral ventral medullary surface (VMS) area from five goats after blood pressure challenges during waking and halothane anesthesia. Reflected 660-nm images were digitized at 1/s after baseline; intravenous saline; 5, 10, or 15 micrograms/kg phenylephrine administration; or sodium nitroprusside infusion sufficient to lower blood pressure by 50%. Phenylephrine elicited a dose-dependent, blood pressure elevation during both states and a substantial transient reflectance increase (interpreted as activity decline) during anesthesia, but only a minimal, long-latency, slow-reflectance decrease activity increase) during waking. Sodium nitroprusside elicited lowering of blood pressure and decreased reflectance in the rostral site during anesthesia. The magnitude of the reflectance change to depressor challenge increased 30%, and the onset latency shortened during waking. Isolated regions of enhanced reflectance changes appeared during both challenges. Activity in this rostral VMS site differentially responds to blood pressure elevation or lowering, and state markedly alters the responses. We speculate that VMS responses to depressor challenge represent reflex activation of respiratory regions.
Author List
Harper RM, Gozal D, Forster HV, Ohtake PJ, Pan LG, Lowry TF, Rector DMAuthor
Hubert V. Forster PhD Professor in the Physiology department at Medical College of WisconsinMESH terms used to index this publication - Major topics in bold
Anesthesia, GeneralAnimals
Blood Pressure
Dose-Response Relationship, Drug
Female
Goats
Medulla Oblongata
Nitroprusside
Phenylephrine
Reaction Time
Sodium Chloride
Urethane
Wakefulness
