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Awasthi JR, Tamada K, Overton ETN, Takumi T. Comprehensive topographical map of the serotonergic fibers in the male mouse brain. J Comp Neurol 2021; 529:1391-1429. [PMID: 32892368 DOI: 10.1002/cne.25027] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2020] [Revised: 08/14/2020] [Accepted: 08/26/2020] [Indexed: 11/11/2022]
Abstract
It is well established that serotonergic fibers distribute throughout the brain. Abnormal densities or patterns of serotonergic fibers have been implicated in neuropsychiatric disorders. Although many classical studies have examined the distribution pattern of serotonergic fibers, most of them were either limited to specific brain areas or had limitations in demonstrating the fine axonal morphology. In this study, we utilize male mice expressing green fluorescence protein under the serotonin transporter (SERT) promoter to map the topography of serotonergic fibers across the rostro-caudal extent of each brain area. We demonstrate previously unreported regional density and fine-grained anatomy of serotonergic fibers. Our findings include: (a) SERT fibers distribute abundantly in the thalamic nuclei close to the midline and dorsolateral areas, in most of the hypothalamic nuclei with few exceptions such as the median eminence and arcuate nuclei, and within the basal amygdaloid complex and lateral septal nuclei, (b) the source fibers of innervation of the hippocampus traverse through the septal nuclei before reaching its destination, (c) unique, filamentous type of straight terminal fibers within the nucleus accumbens, (d) laminar pattern of innervation in the hippocampus, olfactory bulb and cortex with heterogenicity in innervation density among the layers, (e) cortical labeling density gradually decreases rostro-caudally, (f) fibers traverse and distribute mostly within the gray matter, leaving the white fiber bundles uninnervated, and (g) most of the highly labeled nuclei and cortical areas have predominant anatomical connection to limbic structures. In conclusion, we provide novel, regionally specific insights on the distribution map of serotonergic fibers using transgenic mouse.
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Affiliation(s)
- Janak R Awasthi
- RIKEN Brain Science Institute, Wako, Japan.,Graduate School of Science and Engineering, Saitama University, Saitama, Japan
| | | | | | - Toru Takumi
- RIKEN Brain Science Institute, Wako, Japan.,Graduate School of Science and Engineering, Saitama University, Saitama, Japan.,Department of Physiology and Cell Biology, Kobe University School of Medicine, Kobe, Japan
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Borgers AJ, Koopman KE, Bisschop PH, Serlie MJ, Swaab DF, Fliers E, la Fleur SE, Alkemade A. Decreased serotonin transporter immunoreactivity in the human hypothalamic infundibular nucleus of overweight subjects. Front Neurosci 2014; 8:106. [PMID: 24860418 PMCID: PMC4030197 DOI: 10.3389/fnins.2014.00106] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2014] [Accepted: 04/23/2014] [Indexed: 11/24/2022] Open
Abstract
Context: That serotonin plays a role in the regulation of feeding behavior and energy metabolism has been known for a long time. Serotonin transporters (SERT) play a crucial role in serotonin signaling by regulating its availability in the synaptic cleft. The neuroanatomy underlying serotonergic signaling in humans is largely unknown, and until now, SERT immunoreactivity in relation to body weight has not been investigated. Objective: To clarify the distribution of SERT immunoreactivity throughout the human hypothalamus and to compare SERT immunoreactivity in the infundibular nucleus (IFN), the human equivalent of the arcuate nucleus, in lean and overweight subjects. Design: First, we investigated the distribution of serotonin transporters (SERT) over the rostro-caudal axis of six post-mortem hypothalami by means of immunohistochemistry. Second, we estimated SERT immunoreactivity in the IFN of lean and overweight subjects. Lastly, double-labeling of SERT with Neuropeptide Y (NPY) and melanocortin cell populations was performed to further identify cells showing basket-like SERT staining. Results: SERT-immunoreactivity was ubiquitously expressed in fibers throughout the hypothalamus and was the strongest in the IFN. Immunoreactivity in the IFN was lower in overweight subjects (p = 0.036). Basket-like staining in the IFN was highly suggestive of synaptic innervation. A very small minority of cells showed SERT double labeling with NPY, agouti-related protein and α–melanocyte stimulating hormone. Conclusions: SERT is ubiquitously expressed in the human hypothalamus. Strong SERT immunoreactivity, was observed in the IFN a region important for appetite regulation, in combination with lower SERT immunoreactivity in the IFN of overweight and obese subjects, may point toward a role for hypothalamic SERT in human obesity.
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Affiliation(s)
- Anke J Borgers
- Department of Endocrinology and Metabolism, Academic Medical Center, University of Amsterdam Amsterdam, Netherlands
| | - Karin E Koopman
- Department of Endocrinology and Metabolism, Academic Medical Center, University of Amsterdam Amsterdam, Netherlands
| | - Peter H Bisschop
- Department of Endocrinology and Metabolism, Academic Medical Center, University of Amsterdam Amsterdam, Netherlands
| | - Mireille J Serlie
- Department of Endocrinology and Metabolism, Academic Medical Center, University of Amsterdam Amsterdam, Netherlands
| | - Dick F Swaab
- Department of Neuropsychiatric Disorders, Netherlands Institute for Neuroscience, An Institute of the Royal Netherlands Academy of Arts and Sciences Amsterdam, Netherlands
| | - Eric Fliers
- Department of Endocrinology and Metabolism, Academic Medical Center, University of Amsterdam Amsterdam, Netherlands
| | - Susanne E la Fleur
- Department of Endocrinology and Metabolism, Academic Medical Center, University of Amsterdam Amsterdam, Netherlands
| | - Anneke Alkemade
- Department of Endocrinology and Metabolism, Academic Medical Center, University of Amsterdam Amsterdam, Netherlands ; Cognitive Science Center Amsterdam, University of Amsterdam Amsterdam, Netherlands
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Lavezzi AM, Casale V, Oneda R, Weese-Mayer DE, Matturri L. Sudden infant death syndrome and sudden intrauterine unexplained death: correlation between hypoplasia of raphé nuclei and serotonin transporter gene promoter polymorphism. Pediatr Res 2009; 66:22-7. [PMID: 19342987 DOI: 10.1203/pdr.0b013e3181a7bb73] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
This study, besides to delineate the cytoarchitecture and the localization in the brainstem of the human raphé nuclei, aims to evaluate the correlation between neuropathological raphé defects and serotonin transporter gene (5-HTT) promoter region polymorphisms in a cohort of 28 SIDS victims, 12 sudden intrauterine unexplained deaths (SIUD), and 17 controls. Hypoplasia of one or more nuclei of both the rostral and caudal raphé groups was found in 57% of SIDS, in 67% of SIUD, and only in 12% of controls. Furthermore, a significant correlation among 5-HTT Long (L) allele, hypoplasia of the raphé nuclei, and maternal smoking in pregnancy was observed in sudden fetal and infant deaths. The presence of the L allele represents a predisposing factor for sudden fetal and infant death in association with morphologic developmental defects of the raphé nuclei and prenatal smoke exposure. A further consideration of the authors is that SIUD should not be regarded as a separate entity from SIDS, given the potentially shared neuropathological and genetic bases.
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Affiliation(s)
- Anna M Lavezzi
- Department of Surgical, Reconstructive and Diagnostic Sciences, Lino Rossi Research Center for the Study and Prevention of Unexpected Perinatal Death and SIDS, University of Milan, Via Commenda 19, Milan, Italy
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Craven RM, Grahame-Smith DG, Newberry NR. 5-HT1A and 5-HT2 receptors differentially regulate the excitability of 5-HT-containing neurones of the guinea pig dorsal raphe nucleus in vitro. Brain Res 2001; 899:159-68. [PMID: 11311877 DOI: 10.1016/s0006-8993(01)02221-1] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
We have used intracellular recording techniques to examine the effects of 5-hydroxytryptamine (5-HT, serotonin) on 5-HT-containing neurones of the guinea pig dorsal raphe nucleus in vitro. Bath-applied 5-HT (30-300 microM) had two opposing effects on the membrane excitability of these cells, reflecting the activation of distinct 5-HT receptor subtypes. As demonstrated previously in the rat, 5-HT evoked a hyperpolarization and inhibition of 5-HT neurones, which appeared to involve the activation of an inwardly rectifying K(+) conductance. This hyperpolarizing response was blocked by the 5-HT(1A) receptor-selective antagonist WAY-100635 (30-100 nM). In the presence of WAY-100635, 5-HT induced a previously unreported depolarizing, excitatory response of these cells, which was often associated with an increase in the apparent input resistance of the neurone, likely due to the suppression of a K(+) conductance. Like the hyperpolarizing response to 5-HT, this depolarization could be recorded in the presence of the Na(+) channel blocker tetrodotoxin. In addition, the response was not significantly attenuated by the alpha(1)-adrenoceptor antagonist prazosin (500 nM), indicating that it is not due to the release of noradrenaline, or to the direct activation of alpha(1)-adrenoceptors by 5-HT. The 5-HT(3) receptor antagonist granisetron (1 microM) and the 5-HT(4) receptor antagonist SB 204070 (100 nM) failed to reduce the depolarizing response to 5-HT; however, ketanserin (100 nM), mesulergine (100 nM) and lysergic acid diethylamide (1 microM) significantly reduced or abolished the depolarization, indicating that this effect of 5-HT is mediated by 5-HT(2) receptors.
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Affiliation(s)
- R M Craven
- University Department of Clinical Pharmacology, Radcliffe Infirmary, Woodstock Road, OX2 6HE, Oxford, UK.
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Leger L, Charnay Y, Hof PR, Bouras C, Cespuglio R. Anatomical distribution of serotonin-containing neurons and axons in the central nervous system of the cat. J Comp Neurol 2001. [DOI: 10.1002/cne.1133] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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Warembourg M, Deneux D, Krieger M, Jolivet A. Progesterone receptor immunoreactivity in aromatic L-amino acid decarboxylase-containing neurons of the guinea pig hypothalamus and preoptic area. J Comp Neurol 1996; 367:477-90. [PMID: 8731220 DOI: 10.1002/(sici)1096-9861(19960415)367:4<477::aid-cne1>3.0.co;2-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
A double-labeling immunofluorescence procedure was used to determine whether progesterone receptor (PR)-immunoreactive (IR) neurons in the preoptic area and hypothalamus of female guinea pigs also contained aromatic L-amino acid decarboxylase (AADC), an enzyme involved in the synthesis of both catecholamines and serotonin. Immunostaining was performed on cryostat sections prepared from ovariectomized guinea pigs primed by estradiol to induce PR. The nuclear presence of PR was visualized by a red fluorescence while the AADC-containing perikarya showed a yellow-green fluorescence. The topographic distribution of AADC-IR neurons was investigated by using a specific antiserum obtained by immunization of rabbits with a recombinant protein beta-galactosidase-AADC in the two regions known to contain the densest populations of estradiol-induced PR-IR cells: the preoptic area and the mediobasal hypothalamus. The localization of PR-IR and AADC-IR cell populations showed considerable overlap in these areas, mainly in the medial and periventricular preoptic nuclei and in the arcuate nucleus. A quantitative analysis of double-labeled cells estimated that about 15% to 23% of AADC-IR cells in the preoptic area and about 11% to 21% of AADC-IR cells in the arcuate nucleus possessed PR. This colocalization persisted throughout the rostrocaudal extent of these areas and represented 3% to 9% of the population of PR-IR cells. These findings provide neuroanatomical evidence that a subset of AADC neurons is directly regulated by progesterone. The exact physiological role of this enzyme in target cells for progesterone is not understood. AADC may be involved in functions other than that for the synthesis of the classical neurotransmitters.
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Abstract
The dorsal raphe nucleus (DRN) is an important nucleus in pain modulation. It has abundant 5-HT neurons and many other neurotransmitter and/or neuromodulator containing neurons. Its vast fiber connections to other parts of the central nervous system provide a morphological basis for its pain modulating function. Its descending projections, via the nucleus raphe magnus or directly, modulate the responses caused by noxious stimulation of the spinal dorsal horn neurons. In ascending projections, it directly modulates the responses of pain sensitive neurons in the thalamus. It can also be involved in analgesia effects induced by the arcuate nucleus of the hypothalamus. Neurophysiologic and neuropharmacologic results suggest that 5-HT neurons and ENKergic neurons in the DRN are pain inhibitory, and GABA neurons are the opposite. The studies of the intrinsic synapses between ENKergic neurons, GABAergic neurons, and 5-HT neurons within the DRN throw light on their relations in pain modulation functions, and further explain their functions in pain mediation.
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Affiliation(s)
- Q P Wang
- Department of Neurobiology, Shanghai Medical University, China
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Shimizu N, Take S, Hori T, Oomura Y. In vivo measurement of hypothalamic serotonin release by intracerebral microdialysis: significant enhancement by immobilization stress in rats. Brain Res Bull 1992; 28:727-34. [PMID: 1377587 DOI: 10.1016/0361-9230(92)90252-s] [Citation(s) in RCA: 92] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Intracerebral microdialysis was used to measure extracellular serotonin and its metabolite 5-hydroxyindoleacetic acid (5-HIAA) in the hypothalamus of unanesthetized rats. Increase in the concentration of K+ in the perfusing Ringer solution (70 mM) produced a sharp increase in serotonin release, which was significantly attenuated by omitting Ca2+ from the perfusion medium. Intraperitoneal injection of 5-hydroxytryptophan, a precursor of serotonin, or local perfusion of pargyline, a monoamine oxidase inhibitor, elevated the hypothalamic serotonin. Releasers or uptake inhibitors of serotonin, such as fenfluramine, cocaine, mazindol, or imipramine, when added to the perfusion medium, significantly increased serotonin level, whereas 5-HIAA was unaffected by these substances. Immobilization-stress caused an immediate increase in both the extracellular serotonin and 5-HIAA in the hypothalamus, suggesting that the hypothalamic serotonergic system is activated during immobilization stress. The present study indicates that the brain microdialysis is useful for analysis of local changes in serotonin concentration which directly reflect neuronal transmission.
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Affiliation(s)
- N Shimizu
- Department of Physiology, Faculty of Medicine, Kyushu University, Fukuoka, Japan
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Shimizu N, Oomura Y, Kai Y. Stress-induced anorexia in rats mediated by serotonergic mechanisms in the hypothalamus. Physiol Behav 1989; 46:835-41. [PMID: 2628995 DOI: 10.1016/0031-9384(89)90045-0] [Citation(s) in RCA: 73] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The effects of stress on food intake and on neural activity in the lateral hypothalamic area (LHA) were investigated. Significant reduction of daily food intake was observed after 2 hr immobilization. The reduction of body weight was also significant during experimental days. Duplicate injections of methysergide (5 mg/kg, IP) antagonized the immobilization-induced anorexia for 3 hr and injection of naloxone had no effect. Single neuron activity was recorded from a chronically implanted electrode. Activity of 80% of LHA neurons was significantly decreased by immobilization stress. Methysergide significantly attenuated the suppressive effect of immobilization. Further, direct effects of 5-HT on LHA neurons were examined in anesthetized rats. Of 43 LHA neurons tested, the activity of 35 was inhibited by electrophoretic application of 5-HT. These results suggest that immobilization-induced anorexia is mediated at least in part through serotonergic mechanisms in the LHA.
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Affiliation(s)
- N Shimizu
- Department of Physiology, Faculty of Medicine, Kyushu University, Fukuoka, Japan
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Shimizu N, Oomura Y, Aoyagi K. Electrochemical analysis of hypothalamic serotonin metabolism accompanied by immobilization stress in rats. Physiol Behav 1989; 46:829-34. [PMID: 2483461 DOI: 10.1016/0031-9384(89)90044-9] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The effects of stress on serotonin metabolism in the lateral hypothalamic area (LHA) were investigated. Differential pulse voltammetry with a carbon fiber electrode was used to measure 5-hydroxyindoleacetic acid (5-HIAA), the metabolic product of the serotonin (5-HT). High-performance liquid chromatography with electrochemical detection was also used to analyze these compounds in the cerebrospinal fluid (CSF). The peak in voltammogram at an oxidation potential of +230 mV (P3) was identified as 5-HIAA by pharmacological manipulations that are known to affect 5-HT metabolism. A significant increase in 5-HIAA concentration in the LHA was detected after immobilization. An intraperitoneal injection of 5-hydroxytryptophan (5-HTP; a precursor of 5-HT) increased the height of P3, and injection of pargyline prevented the effect of 5-HTP during the course of increasing P3. These results support our previous conclusion that immobilization-induced anorexia might be mediated through activation of serotonergic mechanisms in the LHA.
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Affiliation(s)
- N Shimizu
- Department of Physiology, Faculty of Medicine, Kyushu University, Fukuoka, Japan
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Tillet Y. Early ontogeny of serotonin-immunoreactivity in the sheep brain. An immunohistochemical study. ANATOMY AND EMBRYOLOGY 1988; 178:429-40. [PMID: 3052174 DOI: 10.1007/bf00306049] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Using immunohistochemistry with specific antiserotonin anti-sera, the ontogeny of serotonergic neurons was studied in the foetal sheep brain. Serotonergic-immunoreactive perikarya first appeared rostrally on day 25 of pregnancy, in the medio-ventral part of the mesencephalic flexure, and caudally, on day 28, in the medio-ventral part of the cervical flexure. The development of this system is very rapid, because on day 40 of gestation, all serotonergic nuclei present in the adult were visible. Compared with other species such as rodents or primates, serotonin appears early in the sheep nervous system, and the development of the serotonergic system is even more rapid. Serotonergic immunoreactivity was seen in some cell bodies in the growing adenohypophysis between days 40 and 50. This phenomenon has not been observed in other species. Because serotonin appears very early and is present in growing areas of the nervous system, it could play a trophic role in the development and maturation of the sheep central nervous system, as has been described previously in other species.
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Affiliation(s)
- Y Tillet
- Laboratoire de Neuroendocrinologie, INRA, Centre de Recherches de Tours, Monnaie, France
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Tillet Y. Immunocytochemical localization of serotonin-containing neurons in the myelencephalon, brainstem and diencephalon of the sheep. Neuroscience 1987; 23:501-27. [PMID: 3437977 DOI: 10.1016/0306-4522(87)90073-x] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Using immunocytochemistry, morphological characteristics and distribution of serotonin-containing neurons and fibers of the sheep myelencephalon, brainstem and diencephalon were studied, employing highly specific antibodies to serotonin. The immunocytochemical procedure described here allowed the visualization of endogenous, and thus presumably physiological, pools of serotonin, because no pharmacological treatments (colchicine, inhibitors of monoamine oxidase or 5-hydroxytryptophan) were used to increase the endogenous amount of antigen. The distribution of serotonin cell bodies observed in the study is in agreement with that described by other authors in the rat using a similar method. The present work also shows more numerous groups than the formaldehyde-induced fluorescence method, because five additional groups were revealed, designated S1 to S5. Compared with those in the rat, sheep serotonergic structures exhibit striking specific characteristics: (1) greater scattering of cell bodies within the different groups visualized, (2) absence of group B4 and hypothalamic groups, (3) only a weak serotonergic innervation of the suprachiasmatic nuclei area.
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Affiliation(s)
- Y Tillet
- Laboratoire de Neuroendocrinologie, I.N.R.A. Station de Physiologie de la Reproduction, Nouzilly, France
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Payette RF, Gershon MD, Nunez EA. Colocalization of luteinizing hormone and serotonin in secretory granules of mammalian gonadotrophs. Anat Rec (Hoboken) 1986; 215:51-8. [PMID: 2422987 DOI: 10.1002/ar.1092150108] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Previous studies have demonstrated the uptake of exogenous and storage of endogenous 5-hydroxytryptamine (5-HT) in parenchymal cells of the anterior pituitary. The present experiments were undertaken to test the hypothesis that the endogenous 5-HT of the anterior lobe of the pituitary is costored with beta-luteinizing hormone (beta-LH) within the same secretory granules of gonadotrophs. Electron microscope immunocytochemistry was used to detect 5-HT and beta-LH immunoreactivities in the anterior pituitary glands of mice and bats. Primary antisera generated in different species of animals to these two antigens were localized with appropriate species-specific secondary antisera coupled to colloidal gold particles of different sizes. This enabled 5-HT and beta-LH immunoreactivities to be demonstrated simultaneously on ultrathin sections of fixed anterior lobe tissue mounted on electron microscope (EM) grids. In both bats and mice 5-HT immunoreactivity, identified by immunostaining of beta-LH, was found in gonadotrophs, and in no other cell type. Within gonadotrophs about 25% of the secretory granules were labeled by antisera to both 5-HT and beta-LH, although 100% of granules reacted with the antiserum to B-LH. No secretory granules were found that were immunostained only by the antiserum to 5-HT. It is concluded that endogenous 5-HT may be a normal constituent of mammalian gonadotrophs and that it is colocalized with beta-LH in at least a subset of the secretory granules of these cells. It cannot yet be concluded that gonadotrophs synthesize 5-HT as well as taking it up from the ambient medium.(ABSTRACT TRUNCATED AT 250 WORDS)
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