Halothane anesthesia does not suppress sympathetic activation produced by neuroglucopenia

To determine the suitability of halothane anesthesia for studies of sympathetic control of the endocrine pancreas in dogs, we assessed the effect of halothane anesthesia (0.8% inspired concentration) on the sympathetic response to central neuroglucopenia. In dogs anesthetized with halothane, intravenous administration of the neuroglucopenic agent, 2-deoxy-D-glucose (2-DG; 100 mg/kg), produced increases of both systemic plasma epinephrine (EPI; delta = 269 +/- 86 pg/ml, P less than 0.025) and norepinephrine (NE; delta = 157 +/- 55 pg/ml, P less than 0.025) equivalent to those previously observed in conscious dogs. Measurement of plasma NE kinetics revealed that the plasma NE response to 2-DG during halothane was due to an increase in the rate of NE appearance that was identical to that of conscious dogs, rather than to an impairment of NE clearance. In contrast, 2-DG at this dose did not increase plasma EPI or NE levels in dogs anesthetized with pentobarbital sodium (30 mg/kg). Plasma glucose increased modestly after 2-DG (100 mg/kg) in both conscious and halothane-anesthetized dogs but not in the pentobarbital-anesthetized dogs. Although 2-DG at a threefold higher dose (300 mg/kg) caused plasma EPI, NE, and glucose (delta = 12 +/- 3 mg/dl, P less than 0.001) to increase in pentobarbital-anesthetized dogs, the responses to this higher dose of 2-DG were all significantly larger in halothane-anesthetized dogs (delta of plasma glucose = 30 +/- 8 mg/dl, P less than 0.005; P less than 0.0025 vs. pentobarbital).(ABSTRACT TRUNCATED AT 250 WORDS