Abstract
Previous studies show sympathetic nerve stimulation decreases cerebral blood flow (CBF) in newborn piglets. Effects of α1-antagonist (prazosin) and α2-antagonist (yohimbine) on cerebral sympathetic vasoconstriction were studied. In 21 newborn piglets ventilated (PaCO2=35 mmHg) with 30% N2O, both cervical sympathetic trunks were isolated and CBF was measured (microspheres) during (1) baseline (no stimulation), and (2) electrical stimulation of the right sympathetic trunk (15 Hz, 15 v, and 3 msec). A third CBF measurement was made during sympathetic stimulation following either 0.5 mg/kg, I.V. prazosin (n=11), or yohimbine, 0.5 (n=6) or 1.0 (n=4) mg/kg I.V. Sympathetic nerve stimulation decreased blood flow to ipsilateral cerebrum by −15 ± 2% in comparison to unstimulated side (58 ± 4 and 69 ± 5 ml/min/100g, respectively). Flow to the hippocampus, choroid plexus, and masseter muscle was decreased by −10 ±2, −51 ±5, and −94 ± 5%, respectively. Prazosin inhibited sympathetic vasoconstriction by ∼ 50%, where flow to the ipsilaterai cerebrum, hippocampus, choroid plexus, and masseter muscle was decreased by −8 ±2, −4 ± 3, −7 ± 7, and −53 ± 8%, respectively. Yohimbine had no effect on sympathetic vasoconstriction at 0.5 mg/kg; however, at 1.0 mg/kg, CBF increased from 85 ± 5 to 184 ±44 ml/min/100g. Sympathetic stimulation decreased flow by −23±7, −18 ±4, −47 ±9, and −93 ±3% in the respective regions. The data indicate that sympathetic nerves reduce CBF via α1-adrenoceptor vasoconstriction. In contrast to adult pigs, where α1-adrenergic receptors in cerebral arteries have not been demonstrated, it appears that, in the newborn, α-1 receptors mediate cerebrovascular vasoconstriction.
Article PDF
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Wagerle, L., Delivoria-Papadopoulos, M. 328 ALPHA ADRENERGIC RECEPTOR SUBTYPES IN THE CEREBRAL CIRCULATION OF NEWBORN PIGLETS. Pediatr Res 19, 165 (1985). https://doi.org/10.1203/00006450-198504000-00358
Issue Date:
DOI: https://doi.org/10.1203/00006450-198504000-00358