The involvement of the 5-HT(7) receptor in nociception and pain, particularly chronic pain (i.e., neuropathic pain), has been poorly investigated. In the present study, we examined whether the 5-HT(7) receptor participates in some modulatory control of nerve injury-evoked mechanical hypersensitivity and thermal (heat) hyperalgesia in mice. Activation of 5-HT(7) receptors by systemic administration of the selective 5-HT(7) receptor agonist AS-19 (1 and 10mg/kg) exerted a clear-cut reduction of mechanical and thermal hypersensitivities that were reversed by co-administering the selective 5-HT(7) receptor antagonist SB-258719. Interestingly, blocking of 5-HT(7) receptors with SB-258719 (2.5 and 10mg/kg) enhanced mechanical (but not thermal) hypersensitivity in nerve-injured mice and induced mechanical hypersensitivity in sham-operated mice. Effectiveness of the treatment with a 5-HT(7) receptor agonist was maintained after repeated systemic administration: no tolerance to the antiallodynic and antihyperalgesic effects was developed following treatment with the selective 5-HT(7) receptor agonist E-57431 (10mg/kg) twice daily for 11 days. The 5-HT(7) receptor co-localized with GABAergic cells in the dorsal horn of the spinal cord, suggesting that the activation of spinal inhibitory GABAergic interneurons could contribute to the analgesic effects of 5-HT(7) receptor agonists. In addition, a significant increase of 5-HT(7) receptors was found by immunohistochemistry in the ipsilateral dorsal horn of the spinal cord after nerve injury, suggesting a "pain"-triggered regulation of receptor expression. These results support the idea that the 5-HT(7) receptor subtype is involved in the control of pain and point to a new potential use of 5-HT(7) receptor agonists for the treatment of neuropathic pain.
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http://dx.doi.org/10.1016/j.pain.2010.03.007 | DOI Listing |
Hippocampus
January 2025
Laboratório de Neurobiologia Do Estresse e da Depressão, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP, Brazil.
Serotonin (5-HT) has long been involved in response to stress and its effect may be, in part, mediated by 5-HT1a and 5-HT7 receptor subtypes in different brain structures. Both pre- and post-synaptic activation of 5-HT1a receptor, respectively, in the rat median raphe nucleus (MnRN) and hippocampus, lead to adaptation to acute inescapable stressors such as restraint and forced swim. 5-HT7 receptor (5HT7r), a stimulatory G-protein coupled receptor, has also been investigated as a possible candidate for mediating stress response.
View Article and Find Full Text PDFCell Commun Signal
November 2024
Cellular Neurophysiology, Hannover Medical School, Hannover, Germany.
Background: Homo- and heteromerization of G protein-coupled receptors (GPCRs) plays an important role in the regulation of receptor functions. Recently, we demonstrated an interaction between the serotonin receptor 7 (5-HT7R), a class A GPCR, and the cell adhesion molecule CD44. However, the functional consequences of this interaction on 5-HT7R-mediated signaling remained enigmatic.
View Article and Find Full Text PDFNeuroscience
December 2024
Department of Histology and Embryology, Faculty of Medicine, Istanbul Beykent University, Istanbul, Turkey. Electronic address:
The first of our aims in this study was to investigate the effects of 5-HT2AR, 5-HT7R, and A2AR blockades on miR-27b-3p expression in the short and long-term in neuroblastoma cells. Our second aim was to reduce the expression of pERK and suppress proliferation by blocking the 5-HT2AR with ketanserin. Our third aim was to reduce the expression of pAKT and induce apoptosis by blocking the A2AR and 5-HT7R with MSX3 and SB269970.
View Article and Find Full Text PDFPharmacol Rep
December 2024
Department of Physiology, Maj Institute of Pharmacology, Polish Academy of Sciences, Smętna 12, 31-343, Kraków, Poland.
Background: The study examined the effects of 5-HT receptor activation on GABAergic transmission within the dentate gyrus and plasticity at the glutamatergic perforant path input.
Methods: Immunofluorescence imaging was performed using transverse hippocampal slices from transgenic mice expressing green fluorescent protein (GFP) under the Htr7 promoter. This was followed by whole-cell patch clamp electrophysiological recordings assessing the effects of pharmacologically activating 5-HT receptors on spontaneous inhibitory postsynaptic currents recorded from dentate granule cells and hilar mossy cells-two glutamatergic neuron types present in the dentate gyrus.
Prog Neurobiol
November 2024
College of Osteopathic Medicine of the Pacific, Western University of Health Sciences, Pomona, USA. Electronic address:
Angelman syndrome (AS) is a severe neurodevelopmental disorder characterized by motor disfunction, seizures, intellectual disability, speech deficits, and autism-like behavior, showing high comorbidity with Autism Spectrum Disorders (ASD). It is known that stimulation of the serotonin receptor 7 (5-HT7R) can rescue some of the behavioral and neuroplasticity dysfunctions in animal models of Fragile X and Rett syndrome, two pathologies associated with ASD. In view of these observations, we hypothesised that alterations of 5-HT7R signalling might also be involved in AS.
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