The dorsal raphe nucleus (DRN) projects serotonergic axons throughout the brain and is involved in a variety of physiological functions. However, it also includes a large population of cells that contain other neurotransmitters. To clarify the physiological and pharmacological differences between the serotonergic and nonserotonergic neurons of the DRN, their postsynaptic responses to 5-hydroxytryptamine (5-HT, serotonin) and to selective activation of 5-HT1A or 5-HT2A/C receptors and their action potential characteristics were determined using in vitro patch-clamp recordings. The slices containing these neurons were then immunostained for tryptophan hydroxylase (TPH), a marker of serotonergic neurons. It was found that subpopulations of both serotonergic and nonserotonergic neurons responded to 5-HT with outward (i.e., inhibitory) and inward (i.e., excitatory) currents, responded to both 5-HT1A and 5-HT2A/C receptor activation with outward and inward currents, respectively, and displayed overlapping action potential characteristics. These findings suggest that serotonergic and nonserotonergic neurons in the DRN are both heterogeneous with respect to their individual pharmacological and electrophysiological characteristics. The findings also suggest that the activity of the different populations of DRN neurons will display heterogeneous changes when the serotonergic tone in the DRN is altered by neurological disorders or by drug treatment.
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http://dx.doi.org/10.1152/jn.00437.2004 | DOI Listing |
Microsc Res Tech
December 2024
State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, China.
Serotonin (5-hydroxytryptamine, 5-HT) is a very important neurotransmitter emerging from the raphe nuclei to several brain regions. Serotonergic neuronal connectivity has multiple functions in the brain. In this study, several techniques were used to trace serotonergic neurons in the dorsal raphe (DR) and median raphe (MnR) that project toward the arcuate nucleus of the hypothalamus (Arc), dorsomedial hypothalamic nucleus (DM), lateral hypothalamic area (LH), paraventricular hypothalamic nucleus (PVH), ventromedial hypothalamic nucleus (VMH), fasciola cinereum (FC), and medial habenular nucleus (MHb).
View Article and Find Full Text PDFJ Neurosci Methods
July 2024
Department of Neuroscience, Psychology, Drug Research and Child Health (NEUROFARBA), University of Florence, Viale G. Pieraccini 6, Firenze, 50139, Toscana, Italy. Electronic address:
Background: The serotonergic system modulates brain processes via functionally distinct subpopulations of neurons with heterogeneous properties, including their electrophysiological activity. In extracellular recordings, serotonergic neurons to be investigated for their functional properties are commonly identified on the basis of "typical" features of their activity, i.e.
View Article and Find Full Text PDFDrugs
February 2024
Behavioral Health Service, Ralph H. Johnson VA Medical Center, 109 Bee Street, Charleston, SC, 29401, USA.
Post-traumatic stress disorder (PTSD) is a debilitating disorder inflicting high degrees of symptomatic and socioeconomic burdens. The development of PTSD results from a cascade of events with contributions from multiple processes and the underlying pathophysiology is complex, involving neurotransmitters, neurocircuitry, and neuroanatomical pathways. Presently, only two medications are US FDA-approved for the treatment of PTSD, both selective serotonin reuptake inhibitors (SSRIs).
View Article and Find Full Text PDFSerotonin (5-hydroxytryptamine, 5-HT) signaling plays an important role in dynamic control of peripheral and central nervous system physiology, with altered 5-HT homeostasis implicated in a significant number of disorders, ranging from pulmonary, bowel, and metabolic disease to depression, obsessive-compulsive disorder, and autism spectrum disorder (ASD). The presynaptic, 5-HT transporter (SERT) has a well-established role in regulating 5-HT signaling and is a target of widely prescribed psychotherapeutics, the 5-HT selective reuptake inhibitors (SSRIs). Although SSRI therapy provides symptom relief for many suffering from mood and anxiety disorders, response to these medications is slow (weeks), and too many receive modest or no benefit.
View Article and Find Full Text PDFJ Clin Med
January 2024
Instituto de Investigación Biomédica de Salamanca (IBSAL), Paseo de San Vicente SN, 37007 Salamanca, Spain.
Unlabelled: Treatment-emergent sexual dysfunction (TESD) is one of the most frequent and persistent adverse effects of antidepressant medication. Sexual dysfunction (SD) secondary to SSRIs occurs in >60% of sexually active patients and >80% of healthy volunteers, with this causing treatment discontinuation in >35% of patients. However, this factor is rarely addressed in routine examinations, and only 15-30% of these events are spontaneously reported.
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