Vasoconstriction and neural excitation in response to transient hypoxia in the rat hippocampal slice.

The vascular and neural responses to transient hypoxia in the rat hippocampal slice were studied. Neural hyperexcitability produced by tissue hypoxia was associated with localized decreases in the diameter of precapillary arterioles. Vasoconstriction occurred periodically along the length of vessels observed. The mean percent decrease in vessel diameter in these narrowed regions was 10.25%. Population spikes recorded in the cell body layer of the dentate gyrus showed a mean increase in amplitude of 71.3%. The mean latency to peak response was similar for both the vessels and neurons. The results suggest mechanisms by which autoregulatory influences on microvessel caliber may be counteracted in conditions of hypoxia and hypotension in the whole animal.