There is consistent evidence suggesting that genetic factors play an important role in predisposition to suicidal behavior. Family, twin, and adoption studies have demonstrated that there is a genetic dimension to suicide. Although there is some overlap between suicide and mood disorders, even among psychiatric groups with the highest risk, some patients never attempt suicide, indicating the im...

The effects of 8-OHDPAT and UH-301 injection into the dorsal raphe nucleus (DRN) on fear behavior of the light-dark transitions test and regional brain monoamines (NA, DA, 5-HT) and their metabolites (MHPG, DOPAC, 5-HIAA) in the hypothalamus (HPT), midbrain central gray matter (MID), amygdala (AMY), hippocampus (HIP) and pons (PO) were examined. An injection of 8-OHDPAT (300 ng) as well UH-301 ...

Dopamine, serotonin, and norepinephrine are essential for neurotransmission in the mammalian system. These three neurotransmitters have been the focus of considerable research because the modulation of their production and their interaction at monoamine receptors has profound effects upon a multitude of pharmacological outcomes. Our interest has focused on neurotransmitter reuptake mechanisms i...

A long standing problem with antidepressant drugs is their delayed onsets of action which has made them unsatisfactory in the rapid treatment of serious depressions involving agitated and suicidal behavior. Two new approaches to this problem involve the glutamatergic antagonist, ketamine, recently reviewed, and the acute inhibition of central stress circuits, which is the subject of the present...

The 5-HT re-uptake inhibitor (SSRI) fluoxetine and the adrenal hormone dehydroepiandrosterone (DHEA) both increase the proliferation of progenitor cells in the adult hippocampus and also have antidepressant activity. This paper explores the combined ability of fluoxetine and DHEA to affect this process in the dentate gyrus of adult rats. We show that DHEA can render an otherwise ineffective dos...

During brain development, serotonin (5HT) provides essential neurotrophic signals. In the present study, we evaluated whether the developmental neurotoxicity of chlorpyrifos (CPF) involves effects on 5HT signaling, as a potential mechanism underlying noncholinergic neuroteratogenic events. We evaluated four different treatment windows ranging from the neural tube stage [gestational days (GD) 9-...

The central serotonergic system is comprised of tryptophan hydroxylase-expressing neurons located in the raphe nuclei of the brain stem. Rostral groups of raphe serotonin neurons project throughout the forebrain, while caudal groups innervate the brain stem and spinal cord [1]. The serotonergic system modulates mood [2], anxiety [3], aggression [4], reward systems [5], and impulsivity [6], and ...

Elevating serotonin (5-HT) levels with selective serotonin reuptake inhibitors (SSRIs) is the most widely used treatment for depression. However, current therapies are ineffective, have delayed benefit, or cause side effects in many patients. Here, we define a mechanism downstream of 5-HT1A receptors that mediates antidepressant-like behavior and is profoundly and selectively enhanced by geneti...