RT Journal Article
SR Electronic
T1 Selective Hippocampal Lesions Do Not Increase Adrenocortical Activity
JF The Journal of Neuroscience
JO J. Neurosci.
FD Society for Neuroscience
SP 4345
OP 4354
DO 10.1523/JNEUROSCI.23-10-04345.2003
VO 23
IS 10
A1 Frode A. Tuvnes
A1 Hill-Aina Steffenach
A1 Robert Murison
A1 May-Britt Moser
A1 Edvard I. Moser
YR 2003
UL http://www.jneurosci.org/content/23/10/4345.abstract
AB It has been proposed that the hippocampus exerts a tonic inhibitory influence on the hypothalamic–pituitary–adrenal (HPA) stress axis. This claim rests, in particular, on the upregulation of corticosterone secretion and other measures of HPA activity after nonselective lesions of the hippocampal formation. We measured plasma corticosterone concentrations after selective neurotoxic damage to the hippocampus and the subiculum in rats. Concentrations were estimated during rest in the rat's home cage and at several time points after varying degrees of stress. Lesions of the hippocampus did not increase the concentration of corticosterone relative to control rats in any condition. Temporary inactivation of the hippocampus or the ventral subiculum by infusion of the GABAA receptor agonist muscimol also failed to induce hypersecretion, although hippocampal infusions did impair spatial memory. These results suggest that the hippocampus is not necessary for tonic inhibition of adrenocortical activity and imply that the HPA axis receives efficient negative feedback inhibition from other brain systems too.