The serotonin (5-HT) system is generally considered as a single modulatory system, with broad and diffuse projections. However, accumulating evidence points to the existence of distinct cell groups in the raphe. Here, we review prior evidence for raphe cell heterogeneity, considering different properties of 5-HT neurons, from metabolism to anatomy, and neurochemistry to physiology. We then summ...

Psychological stress-induced hyperthermia is a fundamental autonomic response in mammals. However, the central circuitry underlying this stress response is poorly understood. Here, we sought to identify sympathetic premotor neurons that mediate a hyperthermic response to social defeat stress, a psychological stress model. Intruder rats that were defeated by a dominant resident conspecific exhib...

Over the past 20 years transcranial B-mode sonography (TCS) of brain parenchyma is being increasingly used as a diagnostic tool in movement disorders. The most widely recognised finding for movement disorders has been an increase in echogenicity of the substantia nigra, an area of the midbrain that is affected in idiopathic Parkinson’s disease (IPD). This finding has enabled a reliable diagnosi...

TO THE EDITOR: In a recent Epub issue of the Journal of Neurophysiology, a paper (Masri et al. 2008) appeared in which the authors claim to replicate experiments, but not results, previously obtained in our laboratory (Ahissar et al. 2000; Sosnik et al. 2001). We maintain that Masri et al. 1) did not replicate our experiments, 2) probed the vibrissal system in a different parametric regime, and...

Hyperalgesia was demonstrated during and immediately after termination of tonic immobility in the lizard Anolis carolinensis. Additionally, tonic immobility antagonized morphine-induced analgesia. In conjunction with other research, these data suggest that the response is accompanied by a reduced availability of serotonin, possibly at postsynaptic receptors of raphe neurons.

Amphetamine use is associated with dysphoric states, including heightened anxiety, that emerge within 24h of withdrawal from the drug. Corticotropin-releasing factor increases serotonin release in the central nucleus of the amygdala, and this neurochemical circuitry may play a role in mediating fear and anxiety states. We have previously shown that chronic amphetamine treatment increases cortic...

OBJECTIVES This study aimed to investigate the role of tumor necrosis factor (TNF)-α and the neuronal nitric oxide synthase enzyme in dysregulation of indoleamine 2,3-dioxygenase (IDO) enzyme, and hence serotonin availability in chronic mild stress (CMS), an animal model of depression. METHODS RATS WERE DIVIDED INTO FIVE GROUPS: two control and CMS-exposed for 6 weeks, and another three group...

Yuan, Pu-Qing, and Hong Yang. Hypothyroidism induces Fos-like immunoreactivity in ventral medullary neurons that synthesize TRH. Am. J. Physiol. 277 (Endocrinol. Metab. 40): E927–E936, 1999.—Altered thyroid statuses are associated with autonomic disorders. Thyrotropin-releasing hormone (TRH) in medullary nuclei regulates vagal efferent activity. Induction of Fos-like immunoreactivity (IR) in me...

The combined horseradish peroxidase retrograde transport-peroxidase-antiperoxidase immunohistochemical procedure was utilized in the present study to ascertain the sites of origin of serotonin and neurotensin projections to the rodent nucleus raphe magnus. The major serotonin inputs to the raphe magnus arise from the B-8 and B-9 groups of Dahlstrom and Fuxe (Dahlstrom, A., and K. Fuxe (1964) Ac...