Effect of Interstitial Glucose Infusion on Cortical Blood Flow and Adenosine Concentration after Postischemic Hypoperfusion in Severe Hypoglycemic Piglets.

Kwon, Jeong Taik; Park, Seung Won; Kim, Young Baeg; Min, Byung Kook; Hwang, Sung Nam; Suk, Jong Sik; Choi, Duck Young

Original Article

Journal of Korean Neurosurgical Society 1997;26(1): 19-28.

Jeong Taik Kwon, Seung Won Park, Young Baeg Kim, Byung Kook Min, Sung Nam Hwang, Jong Sik Suk, Duck Young Choi

Department of Neurosurgery, College of Medicine, Chung-Ang University, Seoul, Korea.

ABSTRACT

Hypoglycemia in human neonates often occurs together with hypoxia or hypotension. Although many authors have investigated the biochemical derangements that occur during these events, only a few studies have focused on the regulation and alteration of neonatal cerebral blood flow(CBF) in these settings where adenosine is probably involved in mediating the hyperemic response of newborn brain to hypoglycemia. The goal of this study was to determine whether interstitial fluid concentration of adenosine affect the local CBF following local interstitial glucose infusion in severe hypoglycemic piglets. Global cerebral ischemia was induced in piglets by occlusion of the subclavian and brachiocephalic arteries for 10 minutes. Cortical CBF and interstitial adenosine concentration were measured simultaneously, using combined hydrogen clearance/microdialysis technique for 60 minutes after reperfusion. Severe hypoglycemia(blood glucose<25mg/dl) was induced by regular insulin(25IU/kg) administered 2 hours prior to induction of ischemia. The piglets were allocated to one of three groups: normoglycemia(Group NG), 8; hypoglycemia with local glucose infusion(Group HGG), 5; hypoglycemia without glucose infusion(Group HG), 8. The baseline CBF in Group HG was 39% greater than that in Group NG(p<0.05). Local glucose infusion decreased the CBF to the level of Group NG. CBFs measured after 50 min. of postischemic reperfusion was reduced 39% in Group NG, 70% in Group HG, and 56% in Group HGG compared with each preischemic baseline level. Baseline adenosine concentration in Group HG was 81% greater than that in Group NG(p<0.05). During ischemia, the adenosine concentration markedly increased in all groups. The Group HG and HGG showed significant postischemic reductions in the interstitial adenosine concentration compared to the baseline levels. The postischemic reduction of adenosine concentration was marked in Group HG compared to Group NG(p<0.05). It is concluded that interstitial glucose infusion can restore local CBF and interstitial adenosine level during preischemic period in severe hypoglycemia state, but not definitely during the period of postischemic hypoperfusion.

Key Words: Adenosine; Cerebral blood flow; Cerebral ischemia; Hypoglycemia; Microdialysis; Reperfusion injury