Abstract
Previous studies suggest that adenosine released by tissue may mediate local vasodilation and thus couple local flow to the O2 requirements of the tissue. The present experiments examine the relationship between CMRO2 and CBF in newborn lambs during infusion of adenosine. A total of 17 lambs were divided into two groups. In Group I (n=7) intracarotid infusion of adenosine concentrations of 0.06, 0.12, and 0.24 mg/kg/min increased CBF by 35, 114, and 102%, respectively, suggesting that maximal adenosine effects were attained with 0.12 and 0.24 mg/kg/min. In Group II (n=10) CBF and CMRO2 were determined during infusion 0.24 mg/kg/min adenosine. Of these, 5 served as controls, studied unanesthetized (CMRO2=5.02 ml/min/100g), and 5 were studied anesthetized (alpha-chloralose) to reduce CMRO2 to 2.20 ml/min/100g. In the anesthetized group CBF was decreased to 37±3 ml/min/100g compared to the control group (CBF=87±7 ml/min/100g). Adenosine increased CBF by 113% and 80% in the control and anesthetized lambs respectively. Cerebrovascular resistance was 0.84±0.08 and 2.48±0.25 mmHg/ml/min/100g in the control and anesthetized groups respectively and decreased by 56% and 58% during adenosine infusion. In spite of the concentration of adenosine infused, CBF was less in the anesthetized lambs as a function of the level of CMRO2. Since adenosine action on smooth muscle is receptor mediated, these data would suggest that the relationship between CBF and CMRO2 is intact when adenosine receptors may be saturated.
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Wagerle, L., Belik, J. EFFECT OF ADENOSINE ON CEREBRAL METABOLIC RATE FOR O2 (CMRO2) AND CEREBRAL BLOOD FLOW (CBF) IN NEWBORN LAMBS. Pediatr Res 18 (Suppl 4), 131 (1984). https://doi.org/10.1203/00006450-198404001-00230
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DOI: https://doi.org/10.1203/00006450-198404001-00230