Abstract
Previous work suggests that sympathetic nerve activation may influence CBF in hypoxic or asphyxiated newborn animals. The present experiments investigate the effect of respiratory acidosis on the efficacy of sympathetic nerves on CBF in 5 anesthetized (30% N2O) newborn piglets. The right sympathetic trunk was electrically stimulated for 60s (16 Hz, 15v, 3 msec) while the left side served as control and blood flow to each hemibrain was measured (microspheres) during (1) baseline (no stimulation), (2) stimulation during normocapnia (PCO2=38±2 torr), and (3) stimulation during hypercapnia (PCO2=62±4 torr). During baseline, CBF was 88±6 and 87±7 ml/min/100g in the left and right hemibrain respectively. Sympathetic nerve stimulation decreased flow to the right hemibrain by 6±1% during normocapnia. Most significant vasoconstriction was noted in the cerebrum (CBM) and choroid plexus (CP) where stimulation reduced flow by 8±2 and 60±10% respectively. During hypercapnia where CBF was increased to 294±58 ml/min/100g, sympathetic nerve stimulation decreased flow to the right hemibrain, CBM, and CP by 25±4, 34±4, and 71±8%, respectively. Blood pressure and blood gases were not affected by sympathetic stimulation. These data suggest that activation of sympathetic nerves during normocarbia has minimal effects on CBF in the newborn piglet but profoundly decreases choroid plexus flow. During hypercapnia, however, activation of sympathetic nerves may severely attenuate the vasodilatory capacity of the cerebrovasculature and thus compromise the vascular response of the newborn brain. (NIH T35-HD-07217-10A1)
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Wagerle, L., Kumar, S. & Delivoria-Papadopoulos, M. SYMPATHETIC NERVE STIMULATION ATTENUATES CEREBRAL BLOOD FLOW (CBF) IN HYPERCAPNIC NEWBORN PIGLETS. Pediatr Res 18 (Suppl 4), 384 (1984). https://doi.org/10.1203/00006450-198404001-01744
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DOI: https://doi.org/10.1203/00006450-198404001-01744