THE RESPONSE OF TOTAL AND REGIONAL CEREBRAL BLOOD FLOW TO DEXAMETHSONE (DEX) INFUSION IN NEW BORN PIGLETS DURING NORMOXIA

Abstract

We questioned the effect of DEX (a phospholipase A inhibitor) on total and regional cerebral blood flow during normoxia in spontaneously breathing newborn piglets, age ≤7 days old. The animals were randomly assigned to either a control group receiving saline infusion, serving as controls (n = 7), or a dexamethasone group (DEX) (n = 9) receiving DEX 2mg/kg IV, We have shown that this dose reduces the prostanoids in cerebrospinalfluid (CSF). The organ blood Ilow was measured with the radiolabeled microsphrere technique. The results were (flow expressed as ml/min/100g tissue ± SEM): A significant increase (p<0.05) after DEX infusion in total cerebral blood flow (CBF) (105 ± 12 to 149±22), brainstem (158±22 to 232±40), diencepbalon (129±18 to 185±33), periventricular area (76±9) to 101 ± 16) and hypocampus (74±7 to 100±16). In the cortex, caudate nucleus and cerebcllum, DEX did not tiller blood flow. In the control group there was no differences in blood flow before and after saline infusion, neither in total cerebral nor regional cerebral blood flow. In conclusion, the cerebrum shows regional differences in its response to DEX. Whereas in some parts regional blood flow significantly increased, others did not demonstrate this phenomenon. Thus, the pharmacological properties of DEX do not modulate the cerebral vascular tone equally in all cerebral regions.