Differential distribution of norepinephrine and serotonin along the dorsal-ventral axis of the hippocampal formation.

Norepinephrine (NE) and Serotonin (5-HT) are differentially distributed along the dorsal-ventral axis of the Hippocampal Formation (HF). A kinetic analysis of the uptake of labeled NE and 5-HT was performed to assess the relative density of nerve terminals which accumulate NE and 5-HT (Vmax) and the apparent affinity for uptake (Km). The results reveal a greater density of NE and 5-HT terminals in the ventral HF and a higher Km for 5-HT uptake in the dorsal HF. The results are discussed in terms of potential explanation of reported differences following independent manipulation of the dorsal and ventral hippocampal formation.