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Gedeon JY, Pineda-Farias JB, Gold MS. In-Vivo Calcium Imaging of Sensory Neurons in the Rat Trigeminal Ganglion. J Vis Exp 2024:10.3791/65978. [PMID: 38407223 PMCID: PMC11139451 DOI: 10.3791/65978] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/27/2024] Open
Abstract
Genetically encoded calcium indicators (GECIs) enable imaging techniques to monitor changes in intracellular calcium in targeted cell populations. Their large signal-to-noise ratio makes GECIs a powerful tool for detecting stimulus-evoked activity in sensory neurons. GECIs facilitate population-level analysis of stimulus encoding with the number of neurons that can be studied simultaneously. This population encoding is most appropriately done in vivo. Dorsal root ganglia (DRG), which house the soma of sensory neurons innervating somatic and visceral structures below the neck, are used most extensively for in vivo imaging because these structures are accessed relatively easily. More recently, this technique was used in mice to study sensory neurons in the trigeminal ganglion (TG) that innervate oral and craniofacial structures. There are many reasons to study TG in addition to DRG, including the long list of pain syndromes specific to oral and craniofacial structures that appear to reflect changes in sensory neuron activity, such as trigeminal neuralgia. Mice are used most extensively in the study of DRG and TG neurons because of the availability of genetic tools. However, with differences in size, ease of handling, and potentially important species differences, there are reasons to study rat rather than mouse TG neurons. Thus, we developed an approach for imaging rat TG neurons in vivo. We injected neonatal pups (p2) intraperitoneally with an AAV encoding GCaMP6s, resulting in >90% infection of both TG and DRG neurons. TG was visualized in the adult following craniotomy and decortication, and changes in GCaMP6s fluorescence were monitored in TG neurons following stimulation of mandibular and maxillary regions of the face. We confirmed that increases in fluorescence were stimulus-evoked with peripheral nerve block. While this approach has many potential uses, we are using it to characterize the subpopulation(s) of TG neurons changed following peripheral nerve injury.
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Affiliation(s)
- Jeremy Y Gedeon
- Center for Neuroscience at the University of Pittsburgh; Department of Neurobiology, University of Pittsburgh School of Medicine; Pittsburgh Center for Pain Research, University of Pittsburgh
| | - Jorge Baruch Pineda-Farias
- Department of Neurobiology, University of Pittsburgh School of Medicine; Pittsburgh Center for Pain Research, University of Pittsburgh
| | - Michael S Gold
- Department of Neurobiology, University of Pittsburgh School of Medicine; Pittsburgh Center for Pain Research, University of Pittsburgh;
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Réaux-Le-Goazigo A, Beliard B, Delay L, Rahal L, Claron J, Renaudin N, Rivals I, Thibaut M, Nouhoum M, Deffieux T, Tanter M, Pezet S. Ultrasound localization microscopy and functional ultrasound imaging reveal atypical features of the trigeminal ganglion vasculature. Commun Biol 2022; 5:330. [PMID: 35393515 PMCID: PMC8989975 DOI: 10.1038/s42003-022-03273-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2021] [Accepted: 03/15/2022] [Indexed: 12/26/2022] Open
Abstract
The functional imaging within the trigeminal ganglion (TG) is highly challenging due to its small size and deep localization. This study combined a methodological framework able to dive into the rat trigeminal nociceptive system by jointly providing 1) imaging of the TG blood vasculature at microscopic resolution, and 2) the measurement of hemodynamic responses evoked by orofacial stimulations in anesthetized rats. Despite the small number of sensory neurons within the TG, functional ultrasound imaging was able to image and quantify a strong and highly localized hemodynamic response in the ipsilateral TG, evoked not only by mechanical or chemical stimulations of corneal nociceptive fibers, but also by cutaneous mechanical stimulations of the ophthalmic and maxillary orofacial regions using a von Frey hair. The in vivo quantitative imaging of the TG’s vasculature using ultrasound localization microscopy combined with in toto labelling reveals particular features of the vascularization of the area containing the sensory neurons, that are likely the origin of this strong vaso-trigeminal response. This innovative imaging approach opens the path for future studies on the mechanisms underlying changes in trigeminal local blood flow and evoked hemodynamic responses, key mechanisms for the understanding and treatment of debilitating trigeminal pain conditions. Visualisation of rat trigeminal ganglia activation during ophthalmic or maxillary nociceptive stimulations shows atypical tortuous vascularisation and a somatotopic hemodynamic response.
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Affiliation(s)
| | - Benoit Beliard
- Physics for Medicine Paris, Inserm, ESPCI Paris, CNRS, PSL Research University, 17 rue Moreau, 75012, Paris, France
| | - Lauriane Delay
- Physics for Medicine Paris, Inserm, ESPCI Paris, CNRS, PSL Research University, 17 rue Moreau, 75012, Paris, France
| | - Line Rahal
- Physics for Medicine Paris, Inserm, ESPCI Paris, CNRS, PSL Research University, 17 rue Moreau, 75012, Paris, France
| | - Julien Claron
- Physics for Medicine Paris, Inserm, ESPCI Paris, CNRS, PSL Research University, 17 rue Moreau, 75012, Paris, France
| | - Noémi Renaudin
- Physics for Medicine Paris, Inserm, ESPCI Paris, CNRS, PSL Research University, 17 rue Moreau, 75012, Paris, France
| | - Isabelle Rivals
- Equipe de Statistique Appliquée, ESPCI Paris, PSL Research University, UMRS 1158, 10 rue Vauquelin, 75005, Paris, France
| | - Miguel Thibaut
- Physics for Medicine Paris, Inserm, ESPCI Paris, CNRS, PSL Research University, 17 rue Moreau, 75012, Paris, France
| | - Mohamed Nouhoum
- Physics for Medicine Paris, Inserm, ESPCI Paris, CNRS, PSL Research University, 17 rue Moreau, 75012, Paris, France.,Iconeus, 27 Rue du Faubourg Saint-Jacques, 75014, Paris, France
| | - Thomas Deffieux
- Physics for Medicine Paris, Inserm, ESPCI Paris, CNRS, PSL Research University, 17 rue Moreau, 75012, Paris, France
| | - Mickael Tanter
- Physics for Medicine Paris, Inserm, ESPCI Paris, CNRS, PSL Research University, 17 rue Moreau, 75012, Paris, France
| | - Sophie Pezet
- Physics for Medicine Paris, Inserm, ESPCI Paris, CNRS, PSL Research University, 17 rue Moreau, 75012, Paris, France.
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Hu M, Doyle AD, Yamada KM, Kulkarni AB. Visualization of trigeminal ganglion sensory neuronal signaling regulated by Cdk5. Cell Rep 2022; 38:110458. [PMID: 35263573 PMCID: PMC9004325 DOI: 10.1016/j.celrep.2022.110458] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2021] [Revised: 11/24/2021] [Accepted: 02/08/2022] [Indexed: 02/04/2023] Open
Abstract
The mechanisms underlying facial pain are still incompletely understood, posing major therapeutic challenges. Cyclin-dependent kinase 5 (Cdk5) is a key neuronal kinase involved in pain signaling. However, the regulatory roles of Cdk5 in facial pain signaling and the possibility of therapeutic intervention at the level of mouse trigeminal ganglion primary neurons remain elusive. In this study, we use optimized intravital imaging to directly compare trigeminal neuronal activities after mechanical, thermal, and chemical stimulation. We then test whether facial inflammatory pain in mice could be alleviated by the Cdk5 inhibitor peptide TFP5. We demonstrate regulation of total Ca2+ intensity by Cdk5 activity using transgenic and knockout mouse models. In mice with vibrissal pad inflammation, application of TFP5 specifically decreases total Ca2+ intensity in response to noxious stimuli. It also alleviates inflammation-induced allodynia by inhibiting activation of trigeminal peripheral sensory neurons. Cdk5 inhibitors may provide promising non-opioid candidates for pain treatment.
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Affiliation(s)
- Minghan Hu
- Functional Genomics Section and Cell Biology Section, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD, USA
| | - Andrew D Doyle
- Cell Biology Section, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD, USA
| | - Kenneth M Yamada
- Cell Biology Section, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD, USA.
| | - Ashok B Kulkarni
- Functional Genomics Section, National Institute of Dental and Craniofacial Research, National Institutes of Health, 30 Convent Drive, MSC 4359, Bethesda, MD, USA.
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