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J. A. RIBEIRO AN. R. ACAD. NAC. FARM.

release and subsequent reduction of NMDA-receptor activation (34).

So, adenosine A1-receptor activation by released adenosine depresses
hippocampal synaptic transmission during hypoxia but is a process

that facilitates recovery upon re-oxygenation.

CEREBRAL ISCHEMIA AND TRAUMA

Cerebral ischemia leads to brain damage caused by pathogenetic
mechanisms that are also activated by neurotrauma. These
mechanisms include among others excitotoxicity, overproduction of
free radicals, inflammation and apoptosis. Furthermore, cerebral
ischemia and trauma both trigger similar auto-protective mechanisms
including the production of heat shock proteins, anti-inflammatory
cytokines and endogenous antioxidants. Neuroprotective therapy aims
at minimizing the activation of toxic pathways and at enhancing the
activity of endogenous neuroprotective mechanisms. According to
(18), the similarities in the damage-producing changes in endogenous
substances in the brain may imply that neuroprotective compounds
found to be active against one of these conditions may indeed be also
protective in the other.

Hypothermia

The use of hypothermia to treat various neurological emergencies,
initially introduced into clinical practice in the 1940s and 1950s, had
been considered without interest by the 1980s. However, in the early
1990s, there was a revival of its use in the treatment of severe
traumatic brain injury. The success of mild hypothermia led to the
broadening of its application to many other neurological emergencies.
Mild hypothermia has been applied with varying degrees of success in
many neurological emergencies, including traumatic brain injury,
spinal cord injury, ischemic stroke, subarachnoid haemorrhage out-
of-hospital cardiopulmonary arrest, hepatic encephalopathy, perinatal
asphyxia (hypoxic-anoxic encephalopathy), and infantile viral
encephalopathy. According to (15), there is no total consensus on the
efficacy and safety of mild hypothermia though preliminary clinical
studies have shown that mild hypothermia can be a feasible and

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