Permanent deficits in serotonergic functioning of olfactory bulbectomized rats: an in vivo microdialysis study.

Background: Bilateral removal of the olfactory bulbs (OBX) in rats results in a complex constellation of behavioral, neurochemical, neuroendocrine, and neuroimmune alterations, many of which are also reported in patients with major depressive disorder (MDD). Drawing on clinical findings, there has been considerable interest in the role of serotonin in the mechanism of action of OBX. However, to date, there has been no report of direct measurement of serotonergic functioning of bulbectomized animals using microdialysis.

Effects of dietary tryptophan variations on extracellular serotonin in the dorsal hippocampus of rats.

Rationale: There is evidence to suggest that the efficacy of selective serotonin reuptake inhibitors (SSRIs) in depression is dependent on the availability of serotonin (5-HT) in the brain. Moreover, there is circumstantial evidence suggesting that plasma tryptophan (TRP) levels can predict response to SSRIs. These findings suggest that dietary TRP variations may affect the efficacy of SSRI in major depression.