Pentobarbital anesthesia alters pulmonary vascular response to neural antagonists

Abstract

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/Q) relationship compared with that measured in conscious dogs, and 2) determine whether autonomic nervous system (ANS) regulation of the intact P/Q relationship is altered during pentobarbital. P/Q plots were constructed by graded constriction of the thoracic inferior vena cava, which produced stepwise decreases in Q. Pentobarbital (30 mg/kg iv) had no net effect on the base-line P/Q relationship. In contrast, changes in the conscious intact P/Q relationship in response to ANS antagonists were markedly altered during pentobarbital. Sympathetic alpha-adrenergic receptor block with prazosin caused active pulmonary vasodilation (P less than 0.01) in conscious dogs but caused vasoconstriction (P less than 0.01) during pentobarbital. Sympathetic beta-adrenergic receptor block with propranolol caused active pulmonary vasoconstriction (P less than 0.01) in both groups, but the magnitude of the vasoconstriction was attenuated (P less than 0.05) during pentobarbital at most levels of Q. Finally, cholinergic receptor block with atropine resulted in active pulmonary vasodilation (P less than 0.01) in conscious dogs, whereas vasoconstriction (P less than 0.01) was observed during pentobarbital. Thus, although pentobarbital had no net effect on the base-line P/Q relationship measured in conscious dogs, ANS regulation of the intact pulmonary vascular P/Q relationship was altered during pentobarbital anesthesia.

Concentrated Ambient Air Particles Induce Vasoconstriction of Small Pulmonary Arteries in Rats

“…These morphologic findings are in agreement with other morphologic studies of small pulmonary vessel injury in dogs from areas of high ambient pollution in Mexico City (51). Furthermore, because the animals of the study reported here were sacrificed using an overdose of pentobarbital anesthesia, it is possible that our morphometric studies underestimate the magnitude of the changes because it is known that pentobarbital used as an anesthetic can attenuate vasoconstriction (52,53). In addition, a number of recent studies of pulmonary endotheliumderived mediators responding to ambient particle exposures have been reported (54).…”

Comparison of the effects of isoflurane with those of propofol on pulmonary vascular impedance in experimental embolic pulmonary hypertension

“…Pentobarbitone anaesthesia alone does not affect PAP/Q i relationships in hyperoxic sheep lungs 16 or in normoxic intact dogs, 17 but alters autonomic nervous regulation of the pulmonary circulation. 17 Barbiturates may reduce HPV by 14-28% at clinically relevant doses in isolated sheep lungs, 16 but it is not known if this can be extrapolated to intact animals. How background anaesthesia might interfere with the pulmonary vascular effects of isoflurane is uncertain.…”

The distribution of blood flow and glucose uptake within single skeletal muscles in the awake rabbit

“…Regional blood JEow and regional glucose uptake within single muscles : effect of anaesthesia General anaesthesia alters the baseline circulatory and metabolic status as well as the cardiovascular response to various external stimuli in mammals. This is probably best documented for pentobarbital anaesthesia (Price 1960, Vatner & Braunwald 1975, Micic et al 1978, Zimpfer et al 1982, Nyhan et al 1989). However, expressed as the coefficient of variation, we observed no difference in the extent of regional heterogeneity in blood flow within the muscles from the awake rabbit when compared with that obtained during the subsequently induced anaesthesia in the same animal.…”