Effect of local ischemia on catecholamine and 5-hydroxytryptamine levels in the dog brain.

Sixty-minute partial ischemia (occlusion of a. cerebri media dextra) had no such marked effect on changes in monoamine levels as observed after longer intervals. In differentiated parts of area S II (area of direct damage) there was a significant increase of NE in g. sylvius ant. and g. coronarius in comparison to sham-operated controls, a significant elevation of 5-HT in g. sylvius ant. and lesser nonsignificant dopamine changes in area S II. An interesting finding was that in comparison with monoamine levels in sham-operated controls there were changes in their levels also in the contralateral hemisphere of animals with experimentally induced ischemia. In the other areas monitored there were no changes. These results from unilateral partial brain ischemia are corroborated by the findings of other authors at total brain ischemia and indicate that shorter intervals of ischemia produce only slight reversible changes in monoamines whereas longer intervals produce their reduction and impaired metabolism.