We investigated the effects of pentobarbital sodium anesthesia on vasoregulation of the pulmonary circulation. Our specific objectives were to 1) assess the net effect of pentobarbital on the base-line pulmonary vascular pressure-to-cardiac index (P/Q̇) relationship compared with that measured in conscious dogs, and 2) determine whether autonomic nervous system (ANS) regulation of the intact P/Q̇ relationship is altered during pentobarbital. P/Q̇ plots were constructed by graded constriction of the thoracic inferior vena cava, which produced stepwise decreases in Q̇. Pentobarbital (30 mg/kg iv) had no net effect on the base-line P/Q̇ relationship. In contrast, changes in the conscious intact P/Q̇ relationship in response to ANS antagonists were markedly altered during pentobarbital. Sympathetic α-adrenergic receptor block with prazosin caused active pulmonary vasodilation (P < 0.01) in conscious dogs but caused vasoconstriction (P < 0.01) during pentobarbital. Sympathetic β-adrenergic receptor block with propranolol caused active pulmonary vasoconstriction (P < 0.01) in both groups, but the magnitude of the vasoconstriction was attenuated (P < 0.05) during pentobarbital at most levels of Q̇. Finally, cholinergic receptor block with atropine resulted in active pulmonary vasodilation (P < 0.01) in conscious dogs, whereas vasoconstriction (P < 0.01) was observed during pentobarbital. Thus, although pentobarbital had no net effect on the base-line P/Q̇ relationship measured in conscious dogs, ANS regulation of the intact pulmonary vascular P/Q̇ relationship was altered during pentobarbital anesthesia.
|Original language||English (US)|
|Journal||American Journal of Physiology - Heart and Circulatory Physiology|
|State||Published - 1989|
ASJC Scopus subject areas
- Cardiology and Cardiovascular Medicine
- Physiology (medical)