Rostral ventral medullary surface activity during hypercapnic challenges in awake and anesthetized goats.
Regions within the rostral ventral medullary surface (RVMS) play an important role in cardiorespiratory responses to CO2 during anesthesia. Activity within a RVMS area, in which local cooling elicited marked ventilatory and blood pressure reductions, was measured as 660 nm scattered light changes in 5 goats following 5% CO2 challenges during waking and anesthetic states. During wakefulness, hypercapnia elicited a substantial, short latency transient (1-1.5 min) activity increase, followed by a sustained decrease. Stimulus cessation elicited a large and rapid off-transient activity increase which persisted for approximately 20 min. In contrast, during halothane anesthesia, the initial activation was absent, and the later activity decline and off-response were much reduced. We conclude that biphasic RVMS activity responses emerge to CO2 stimulation, and are state-dependent.
Gozal
D
D
Department of Anatomy and Cell Biology, University of California at Los Angeles School of Medicine 90095-1763, USA.
Ohtake
P J
PJ
Rector
D M
DM
Lowry
T F
TF
Pan
L G
LG
Forster
H V
HV
Harper
R M
RM
D000280:Administration, Inhalation; D000758:Anesthesia; D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D002245:Carbon Dioxide / Q000494:pharmacology; D005260:Female; D006041:Goats; D006935:Hypercapnia / Q000503:physiopathology*; D008027:Light; D008526:Medulla Oblongata / Q000187:drug effects / Q000503:physiopathology*; D055095:Optics and Photonics; D011930:Reaction Time; D012119:Respiration / Q000187:drug effects; D012542:Scattering, Radiation; D014851:Wakefulness
D002245:Carbon Dioxide