Long Term Changes in Nadph-Diaphorase Reactivity in Striatal and Cortical Neurons Following Experimental Perinatal Asphyxia: Neuroprotective Effects of Hypothermia

Abstract
Nitric oxide (NO) is known to be involved in the neuropathological mechanisms triggered by excitatory aminoacids. NO(+) neurons in the brain may be detected histochemically by nicotinamide adenine dinucleotide phosphate diaphorase (NADPH-d) histochemical technique, as the latter readily labels NO synthase in the central nervous system (CNS). NADPH-d stained striatal and cortical sections were studied in 6-month-old male Sprague-Dawley rats exposed to perinatal asphyxia (PA) at 37°C. as well as in animals subjected to PA plus hypothermia treatment at 15°C. Quantitative image analysis was performed to compare the staining pattern in the various groups. NADPH-d(+) neurons in striatum and cortex from subsevere and severe asphyctic animals showed a significant increase in soma size and in dendritic processes versus controls and hypothermia-treated rats. These findings indicate that chronic NO changes are involved in postischemic striatal and cortical alterations induced by PA that may be prevented by hypothermia.