title: Effect of bilateral carotid body resection on cardiac baroreflex control of blood pressure during hypoglycemia.
abstract: Hypoglycemia results in a reduction in cardiac baroreflex sensitivity and a shift in the baroreflex working range to higher heart rates. This effect is mediated, in part, by the carotid chemoreceptors. Therefore, we hypothesized hypoglycemia-mediated changes in baroreflex control of heart rate would be blunted in carotid body-resected patients when compared with healthy controls. Five patients with bilateral carotid body resection for glomus tumors and 10 healthy controls completed a 180-minute hyperinsulinemic, hypoglycemic (≈3.3 mmol/L) clamp. Changes in heart rate, blood pressure, and spontaneous cardiac baroreflex sensitivity were assessed. Baseline baroreflex sensitivity was not different between groups (P>0.05). Hypoglycemia resulted in a reduction in baroreflex sensitivity in both the groups (main effect of time, P<0.01) and responses were lower in resected patients when compared with controls (main effect of group, P<0.05). Hypoglycemia resulted in large reductions in systolic (-17±7 mm Hg) and mean (-14±5 mm Hg) blood pressure in resected patients that were not observed in controls (interaction of group and time, P<0.05). Despite lower blood pressures, increases in heart rate with hypoglycemia were blunted in resected patients (interaction of group and time, P<0.01). Major novel findings from this study demonstrate that intact carotid chemoreceptors are essential for increasing heart rate and maintaining arterial blood pressure during hypoglycemia in humans. These data support a contribution of the carotid chemoreceptors to blood pressure control and highlight the potential widespread effects of carotid body resection in humans.
authors: Department of Physiology, Michigan State University, East Lansing (E.A.W.); Departments of Anesthesiology (J.K.L., J.L.T., M.T.M., T.B.C., M.J.J.), and Endocrinology (S.D., A.B., R.B., R.A.R.), Mayo Clinic, Rochester, MN.
authors: Jacqueline K
authors: JK
authors: Limberg
authors: Department of Physiology, Michigan State University, East Lansing (E.A.W.); Departments of Anesthesiology (J.K.L., J.L.T., M.T.M., T.B.C., M.J.J.), and Endocrinology (S.D., A.B., R.B., R.A.R.), Mayo Clinic, Rochester, MN.
authors: Jennifer L
authors: JL
authors: Taylor
authors: Department of Physiology, Michigan State University, East Lansing (E.A.W.); Departments of Anesthesiology (J.K.L., J.L.T., M.T.M., T.B.C., M.J.J.), and Endocrinology (S.D., A.B., R.B., R.A.R.), Mayo Clinic, Rochester, MN.
authors: Michael T
authors: MT
authors: Mozer
authors: Department of Physiology, Michigan State University, East Lansing (E.A.W.); Departments of Anesthesiology (J.K.L., J.L.T., M.T.M., T.B.C., M.J.J.), and Endocrinology (S.D., A.B., R.B., R.A.R.), Mayo Clinic, Rochester, MN.
authors: Simmi
authors: S
authors: Dube
authors: Department of Physiology, Michigan State University, East Lansing (E.A.W.); Departments of Anesthesiology (J.K.L., J.L.T., M.T.M., T.B.C., M.J.J.), and Endocrinology (S.D., A.B., R.B., R.A.R.), Mayo Clinic, Rochester, MN.
authors: Ananda
authors: A
authors: Basu
authors: Department of Physiology, Michigan State University, East Lansing (E.A.W.); Departments of Anesthesiology (J.K.L., J.L.T., M.T.M., T.B.C., M.J.J.), and Endocrinology (S.D., A.B., R.B., R.A.R.), Mayo Clinic, Rochester, MN.
authors: Rita
authors: R
authors: Basu
authors: Department of Physiology, Michigan State University, East Lansing (E.A.W.); Departments of Anesthesiology (J.K.L., J.L.T., M.T.M., T.B.C., M.J.J.), and Endocrinology (S.D., A.B., R.B., R.A.R.), Mayo Clinic, Rochester, MN.
authors: Robert A
authors: RA
authors: Rizza
authors: Department of Physiology, Michigan State University, East Lansing (E.A.W.); Departments of Anesthesiology (J.K.L., J.L.T., M.T.M., T.B.C., M.J.J.), and Endocrinology (S.D., A.B., R.B., R.A.R.), Mayo Clinic, Rochester, MN.
authors: Timothy B
authors: TB
authors: Curry
authors: Department of Physiology, Michigan State University, East Lansing (E.A.W.); Departments of Anesthesiology (J.K.L., J.L.T., M.T.M., T.B.C., M.J.J.), and Endocrinology (S.D., A.B., R.B., R.A.R.), Mayo Clinic, Rochester, MN. Joyner.michael@mayo.edu.
authors: Michael J
authors: MJ
authors: Joyner
authors: Department of Physiology, Michigan State University, East Lansing (E.A.W.); Departments of Anesthesiology (J.K.L., J.L.T., M.T.M., T.B.C., M.J.J.), and Endocrinology (S.D., A.B., R.B., R.A.R.), Mayo Clinic, Rochester, MN.
authors: Erica A
authors: EA
authors: Wehrwein
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D017704:Baroreflex / Q000502:physiology*; D001794:Blood Pressure / Q000502:physiology*; D001795:Blood Pressure Determination / Q000379:methods; D002344:Carotid Body / Q000601:surgery*; D002345:Carotid Body Tumor / Q000601:surgery; D016022:Case-Control Studies; D002628:Chemoreceptor Cells / Q000502:physiology; D005260:Female; D015309:Glucose Clamp Technique; D006321:Heart; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D007003:Hypoglycemia / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D012016:Reference Values; D012494:Sampling Studies; D055815:Young Adult
keywords: blood pressure; carotid body tumor; chemoreceptor cells; glucose