scholarly journals In Vivo Analysis of Proprioceptive Coding and Its Antidromic Modulation in the Freely Behaving Crayfish

2005 ◽  
Vol 94 (2) ◽  
pp. 1013-1027 ◽  
Author(s):  
Didier Le Ray ◽  
Denis Combes ◽  
Cyril Déjean ◽  
Daniel Cattaert
Keyword(s):  
Motor Activity ◽  
Action Potentials ◽  
Physiological State ◽  
Sensory Nerve ◽  
Sensory Nerves ◽  
Chordotonal Organ ◽  
Electromyographic Activity ◽  
Sensory Coding ◽  
Freely Behaving

Although sensory nerves in vitro are known to convey both orthodromic (sensory) and antidromic (putatively modulating) action potentials, in most cases very little is known about their bidirectional characteristics in intact animals. Here, we have investigated both the sensory coding properties and antidromic discharges that occur during real walking in the freely behaving crayfish. The activity of the sensory nerve innervating the proprioceptor CBCO, a chordotonal organ that monitors both angular movement and position of the coxo-basipodite (CB) joint, which is implicated in vertical leg movements, was recorded chronically along with the electromyographic activity of the muscles that control CB joint movements. Two wire electrodes placed on the sensory nerve were used to discriminate orthodromic from antidromic action potentials and thus allowed for analysis of both sensory coding and antidromic discharges. A distinction is proposed between 3 main classes of sensory neuron, according to their firing in relation to levator muscle activity during free walking. In parallel, we describe 2 types of antidromic activity: one produced exclusively during motor activity and a second produced both during and in the absence of motor activity. A negative correlation was found between the activity of sensory neurons in each of the 3 classes and identified antidromic discharges during walking. Finally, a state-dependent plasticity of CBCO nerve activity has been found by which the distribution of sensory orthodromic and antidromic activity changes with the physiological state of the biomechanical apparatus.

Inhibitory Component of the Resistance Reflex in the Locomotor Network of the Crayfish

2002 ◽  
Vol 88 (5) ◽  
pp. 2575-2588 ◽  
Author(s):  
Morgane Le Bon-Jego ◽  
Daniel Cattaert
Keyword(s):  
Sensory Nerve ◽  
Chloride Concentration ◽  
Chordotonal Organ ◽  
Bathing Solution ◽  
Postsynaptic Potentials ◽  
Inhibitory Pathways ◽  
In Series ◽  
Chloride Channel Blocker ◽  
Inhibitory Components

The aim of this study was to investigate the inhibitory components of a resistance reflex in the walking system of the crayfish. This study was performed using an in vitro preparation of several thoracic ganglia including motor nerves and the proprioceptor that codes movements of the second joint (coxo-basipodite chordotonal organ—CBCO). Sinusoidal movements were imposed on the CBCO, and intracellular responses were recorded from levator (Lev) and depressor (Dep) motoneurons (MNs). We found that in MNs that oppose the imposed movements (e.g., the Lev MNs during the imposed downward movement), the response consists in a depolarization resulting from the summation of excitatory postsynaptic potentials (EPSPs). A movement in the opposite direction resulted in hyperpolarization during which inhibitory postsynaptic potentials (IPSPs) summated. The inhibitory pathway to each MN is oligosynaptic (i.e., composed of a small number of neurons in series) and involves spiking interneurons because it was blocked in the presence of a high-divalent cation solution. The IPSPs were mediated by a chloride conductance because their amplitude was sensitive to the chloride concentration of the bathing solution and because they were blocked by the chloride channel blocker, picrotoxin. Resistance reflex IPSPs related to single CBCO neurons could be identified. These unitary IPSPs were blocked in the presence of 3-mercapto-propionic acid, an inhibitor of gamma-amino-butyric acid (GABA) synthesis, indicating that they are mediated by GABA. In addition to this GABAergic pathway, electrical stimulation of the CBCO sensory nerve induced compound IPSPs that were blocked by glutamate pyruvate transaminase (GPT), indicating the presence of glutamatergic inhibitory pathways. These glutamatergic interneurons do not appear to be involved in the resistance reflex, however, as GPT did not block the unitary IPSPs. Functionally, the resistance reflex is mainly supported by movement-coding CBCO sensory neurons. We demonstrate that such movement-coding CBCO neurons produce both monosynaptic EPSPs in the MNs opposing imposed movements and oligosynaptic IPSPs in the antagonistic motoneurons. These results highlight the similarities between the inhibitory pathways in resistance reflex of the crayfish and in the stretch reflex of vertebrates mediated by Ia inhibitory interneurons.

Capsaicin-sensitive afferent nerves activate submucosal secretomotor neurons in guinea pig ileum

1995 ◽  
Vol 269 (2) ◽  
pp. G203-G209 ◽  
Author(s):  
S. Vanner ◽  
W. K. MacNaughton
Keyword(s):  
Guinea Pig ◽  
Ion Transport ◽  
Short Circuit ◽  
Ussing Chamber ◽  
Sensory Nerve ◽  
Nerve Fibers ◽  
Sensory Nerves ◽  
Guinea Pig Ileum ◽  
Secretomotor Neurons

This study examined whether capsaicin-sensitive sensory nerves regulate intestinal ion transport using both Ussing chamber and intracellular recording techniques in in vitro submucosal preparations from the guinea pig ileum. In Ussing chamber studies, serosal application of capsaicin (20 nM-20 microM) evoked a biphasic dose-dependent increase in short-circuit current (Isc) (maximal effective concentration 200 nM and 2 microM, respectively). In chloride-free buffer, capsaicin responses were significantly reduced. Capsaicin evoked little or no response when extrinsic sensory nerve fibers had been surgically removed and tetrodotoxin and low-calcium and high-magnesium solutions blocked responses to capsaicin. In epithelial preparations devoid of submucosal neurons, capsaicin had virtually no effect, suggesting that responses evoked by capsaicin-sensitive nerves result from activation of submucosal secretomotor neurons. Intracellular recordings from single submucosal neurons demonstrated that superfusion with capsaicin (2 microM) depolarized neurons with an associated decreased conductance. Depolarizations were completely desensitized when capsaicin was reapplied, but synaptic inputs were unaffected. This study suggests that capsaicin-sensitive nerves can regulate ion transport in the gastrointestinal tract by release of neurotransmitter(s) that activate submucosal secretomotor neurons.

TRPA1 in bradykinin-induced mechanical hypersensitivity of vagal C fibers in guinea pig esophagus

2009 ◽  
Vol 296 (2) ◽  
pp. G255-G265 ◽  
Author(s):  
Shaoyong Yu ◽  
Ann Ouyang
Keyword(s):  
Guinea Pig ◽  
Action Potentials ◽  
Transient Receptor Potential ◽  
Ex Vivo ◽  
Sensory Nerve ◽  
Sensory Nerves ◽  
Peripheral Sensitization ◽  
Nerve Terminals ◽  
Mechanical Hypersensitivity ◽  
C Fibers

Bradykinin (BK) activates sensory nerves and causes hyperalgesia. Transient receptor potential A1 (TRPA1) is expressed in sensory nerves and mediates cold, mechanical, and chemical nociception. TRPA1 can be activated by BK. TRPA1 knockout mice show impaired responses to BK and mechanical nociception. However, direct evidence from sensory nerve terminals is lacking. This study aims to determine the role of TRPA1 in BK-induced visceral mechanical hypersensitivity. Extracellular recordings of action potentials from vagal nodose and jugular neurons are performed in an ex vivo guinea pig esophageal-vagal preparation. Peak frequencies of action potentials of afferent nerves evoked by esophageal distension and chemical perfusion are recorded and compared. BK activates most nodose and all jugular C fibers. This activation is repeatable and associated with a significant increase in response to esophageal distension, which can be prevented by the B2 receptor antagonist WIN64338. TRPA1 agonist allyl isothiocyanate (AITC) activates most BK-positive nodose and jugular C fibers. This is associated with a transient loss of response to mechanical distensions and desensitization to a second AITC perfusion. Desensitization with AITC and pretreatment with TRPA1 inhibitor HC-030031 both inhibit BK-induced mechanical hypersensitivity but do not affect BK-evoked activation in nodose and jugular C fibers. In contrast, esophageal vagal afferent Aδ fibers do not respond to BK or AITC and fail to show mechanical hypersensitivity after BK perfusion. This provides the first evidence directly from visceral sensory afferent nerve terminals that TRPA1 mediates BK-induced mechanical hypersensitivity. This reveals a novel mechanism of visceral peripheral sensitization.

scholarly journals Sensory nerves directly promote osteoclastogenesis by secreting Cyp40

2021 ◽  
Author(s):  
Guo-Xian Pei ◽  
Liu Yang ◽  
Junqin Li ◽  
Bin Liu ◽  
Hao Wu ◽  
...  
Keyword(s):  
Bone Resorption ◽  
Bone Repair ◽  
Bone Cells ◽  
Critical Role ◽  
Sensory Nerve ◽  
Sensory Nerves ◽  
Blue Staining ◽  
Double Labeling ◽  
Sensory Hypersensitivity

Abstract BackgroundGiven the afferent functions, sensors have been found exerting efferent influences and directly alter organ physiology. Sensory nerves have been found critical in osteoclasts and bone resorption. However, the direct evidence of whether sensory nerve efferent influences osteoclast, remains lacking. MethodsWe treated mice with resiniferatoxin (RTX) or complete Freund’s adjuvant (CFA) to induce sensory hypersensitivity. Bone histomorphometry including micro-ct, three-point bending assay, von kossa staining, calcein double labeling, toluidine blue staining, and trap staining were performed to monitor bone quality and bone cells. Multiple virus vectors were applied to trace signals between sensory nerves and osteoclasts. Sensory neurons (SN) and osteoclasts were cocultured to study the effects and mechanisms of the sensory nerves on osteoclasts in vitro. Isobaric tag for relative and absolute quantitation (iTRAQ) was used to identify secreted proteins in the sensory nerve. ResultsHere, we found sensory hypersensitivity significantly increased osteoclast bone resorption; SN directly promote osteoclastogenesis in vitro; and abundant sensory efferent signals transported into osteoclasts. Then our screening identified a novel neuropeptide Peptidyl-prolyl cis-trans isomerase D (Cyp40), is the reverse signal from the sensory nerve and plays a critical role for osteoclastogenesis, via aryl hydrocarbon receptor (AhR)-Ras/Raf-pErk-NFATc1 pathway. The efferent signals from sensory nerves tend to involves in the rapid feedback process: vast majority of sensory efferent signals (87.28%) present in fast-twitch myofibers. ConclusionThis study revealed a novel mechanism of sensory nerves on osteoclasts: the direct promotion of osteoclastogenesis by the Cyp40. This mechanism may represent a direct, and quick response of sensory nerves to the changes in bone. Targeting the Cyp40 could therefore be a strategy to promote bone repair at the early stage of bone injury.

scholarly journals Myeloid-to-mesenchymal NGF-p75 signaling coordinates skeletal cell migration during repair

2021 ◽  
Author(s):  
Jiajia Xu ◽  
Zhao Li ◽  
Robert J. Tower ◽  
Stefano Negri ◽  
Yiyun Wang ◽  
...  
Keyword(s):  
Cancer Biology ◽  
Bone Repair ◽  
Sensory Nerve ◽  
Sensory Nerves ◽  
Cellular Migration ◽  
Conditional Deletion ◽  
Mesenchymal Precursor Cells ◽  
High Affinity Receptor ◽  
Affinity Receptor

Tissue repair relies on the coordination of mesenchymal precursor cells (MPCs) which migrate into the injury site, along with the invasion of blood vessels and sensory nerves. Our prior observations found that the neurotrophin Nerve growth factor (NGF) regulates sensory nerve ingrowth to skeletal repair sites via its high-affinity receptor. A body of work in cancer biology suggest that neurotrophins also engage their low-affinity receptor p75 to mediate cellular migration. Here, we observed conditional deletion of p75 in MPCs or osteoblasts to disrupt bone repair independent of neurovascular ingrowth. Single cell sequencing identified defects in migration and wound healing among MPC populations. Deletion of Ngf among myeloid cells phenocopied p75 conditional deletion animals. In vitro studies confirmed a myeloid-to-mesenchymal NGF-p75 axis which operates to induce cellular migration. Together, our data suggest a direct effect of myeloid-derived NGF on progenitor cells, in parallel to sensory nerve recruitment, required for injury repair.

Spatial transcriptomics reveals a role for sensory nerves in preserving cranial suture patency through modulation of BMP/TGF-β signaling

2021 ◽  
Vol 118 (42) ◽  
pp. e2103087118
Author(s):  
Robert J. Tower ◽  
Zhu Li ◽  
Yu-Hao Cheng ◽  
Xue-Wei Wang ◽  
Labchan Rajbhandari ◽  
...  
Keyword(s):  
Signaling Pathway ◽  
Sensory Nerve ◽  
Positive Association ◽  
Sensory Nerves ◽  
Cranial Bone ◽  
Morphogenetic Protein ◽  
Proliferation And Differentiation ◽  
Microfluidic Chambers

The patterning and ossification of the mammalian skeleton requires the coordinated actions of both intrinsic bone morphogens and extrinsic neurovascular signals, which function in a temporal and spatial fashion to control mesenchymal progenitor cell (MPC) fate. Here, we show the genetic inhibition of tropomyosin receptor kinase A (TrkA) sensory nerve innervation of the developing cranium results in premature calvarial suture closure, associated with a decrease in suture MPC proliferation and increased mineralization. In vitro, axons from peripheral afferent neurons derived from dorsal root ganglions (DRGs) of wild-type mice induce MPC proliferation in a spatially restricted manner via a soluble factor when cocultured in microfluidic chambers. Comparative spatial transcriptomic analysis of the cranial sutures in vivo confirmed a positive association between sensory axons and proliferative MPCs. SpatialTime analysis across the developing suture revealed regional-specific alterations in bone morphogenetic protein (BMP) and TGF-β signaling pathway transcripts in response to TrkA inhibition. RNA sequencing of DRG cell bodies, following direct, axonal coculture with MPCs, confirmed the alterations in BMP/TGF-β signaling pathway transcripts. Among these, the BMP inhibitor follistatin-like 1 (FSTL1) replicated key features of the neural-to-bone influence, including mitogenic and anti-osteogenic effects via the inhibition of BMP/TGF-β signaling. Taken together, our results demonstrate that sensory nerve-derived signals, including FSTL1, function to coordinate cranial bone patterning by regulating MPC proliferation and differentiation in the suture mesenchyme.

scholarly journals Prostaglandin D2 and the role of the DP1, DP2 and TP receptors in the control of airway reflex events

2014 ◽  
Vol 45 (4) ◽  
pp. 1108-1118 ◽  
Author(s):  
Sarah A. Maher ◽  
Mark A. Birrell ◽  
John J. Adcock ◽  
Michael A. Wortley ◽  
Eric D. Dubuis ◽  
...  
Keyword(s):  
Guinea Pig ◽  
Receptor Agonist ◽  
Sensory Nerve ◽  
Sensory Nerves ◽  
Vagal Afferents ◽  
Prostaglandin D2 ◽  
Airway Reflex ◽  
Guinea Pig Model

Prostaglandin D2 (PGD2) causes cough and levels are increased in asthma suggesting that it may contribute to symptoms. Although the prostaglandin D2 receptor 2 (DP2) is a target for numerous drug discovery programmes little is known about the actions of PGD2 on sensory nerves and cough.We used human and guinea pig bioassays, in vivo electrophysiology and a guinea pig conscious cough model to assess the effect of prostaglandin D2 receptor (DP1), DP2 and thromboxane receptor antagonism on PGD2 responses.PGD2 caused cough in a conscious guinea pig model and an increase in calcium in airway jugular ganglia. Using pharmacology and receptor-deficient mice we showed that the DP1 receptor mediates sensory nerve activation in mouse, guinea pig and human vagal afferents. In vivo, PGD2 and a DP1 receptor agonist, but not a DP2 receptor agonist, activated single airway C-fibres. Interestingly, activation of DP2 inhibited sensory nerve firing to capsaicin in vitro and in vivo.The DP1 receptor could be a therapeutic target for symptoms associated with asthma. Where endogenous PGD2 levels are elevated, loss of DP2 receptor-mediated inhibition of sensory nerves may lead to an increase in vagally associated symptoms and the potential for such adverse effects should be investigated in clinical studies with DP2 antagonists.

STEROID HORMONE METABOLISM IN RESPONSIVE TISSUES IN VITRO

1971 ◽  
Vol 68 (1_Suppl) ◽  
pp. S279-S294 ◽  
Author(s):  
Paul Robel
Keyword(s):  
Steroid Hormone ◽  
Physiological Activity ◽  
Physiological State ◽  
Target Cells ◽  
Target Tissue ◽  
Hormone Metabolism ◽  
Metabolizing Enzymes ◽  
Relationship Of

ABSTRACT Of the information available on steroid hormone metabolism in responsive tissues, only that relating hormone metabolism to physiological activity is reviewed, i. e. metabolite activity in isolated in vitro systems, binding of metabolites to target tissue receptors, specific steroid hormone metabolizing enzymes and relationship of hormone metabolism to target organ physiological state. Further, evidence is presented in the androgen field, demonstrating 5α-reduced metabolites, formed inside the target cells, as active compounds. This has led to a consideration of testosterone as a »prehormone«. The possibility that similar events take place in tissues responding to progesterone is discussed. Finally, the role of hormone metabolism in the regulation of hormone availability and/or renewal in target cells is discussed. In this context, reference is made to the potential role of plasma binding proteins and cytosol receptors.

ASSOCIATION OF BDKRB2 AND ACE GENE POLYMORPHISM WITH ERYTHROCYTE ADRENOREACTIVITY IN YOUNG MEN WITH DIFFERENT MOTOR ACTIVITY

2020 ◽  
pp. 96-107
Author(s):  
A.Z. Dautova ◽  
E.A. Khazhieva ◽  
V.G. Shamratova ◽  
L.Z. Sadykova
Keyword(s):  
Gene Polymorphism ◽  
Angiotensin Converting Enzyme ◽  
Motor Activity ◽  
Receptor Gene ◽  
Young Men ◽  
Converting Enzyme ◽  
Ace Gene ◽  
Ace Gene Polymorphism ◽  
Physically Inactive

The aim of the paper was to study the association of polymorphic variants of rs4646994 (I/D) of the angiotensin converting enzyme gene (ACE) and rs5810761 (+9/-9) of the bradykinin B2 receptor gene (BDKRB2) with erythrocyte adrenoreactivity (ARE) in athletes and untrained young men. Materials and Methods. The study involved 61 young men (aged 21–23) with different levels of motor activity (MA). ARE was evaluated according to the erythrocyte sedimentation rate (ESR) change under adrenaline in vitro at final concentrations 10-5, 10-6, 10-7, 10-9, 10-11, 10-13 g/ml of venous blood. According to the effect observed and ESR shifts under adrenaline, we distinguished 3 ARE types: antiaggregative (AnAg), areactive (Ar) and aggregative (Ar). Results. The results of comparative and correlation analyses demonstrated that young athletes with +9/-9 (BDKRB2) genotype were characterized by a higher aggregative resistance of erythrocytes to the effects of both physiological (<10-9 g/ml) (physiological adrenaline concentration, PAC) and stressful doses (>10-9 g/ml) of adrenaline (stress adrenaline concentration, SAC), as well as by predominance of AnAg and Ar ARE types. In athletes, among the representatives of different genotypes of АСЕ gene I/D polymorphism, the erythrocyte response to adrenaline did not have any statistically significant differences. In physically inactive students, namely individuals with the D/D genotype, maximal ESR deviation under PAC was less than in those with I/D genotype. Conclusion. Athletes with *-9 allele (+9/-9 genotype) in their genotype can be considered more stress-resistant, which is provided by optimal adaptive and compensatory body mechanisms. Apparently, resistance of cells to the adrenaline contributes much to the work of these mechanisms. As for the ACE gene polymorphism, its effect on the suspension characteristics of erythrocytes is less pronounced not only in physically inactive young men, but in athletes as well. Keywords: erythrocyte adrenoreactivity (ARE), stress tolerance, β2 bradykinin receptor gene (BDKRB2), angiotensin converting enzyme (ACE) gene, motor activity. Цель работы – изучить ассоциацию полиморфных вариантов rs4646994 (I/D) гена ангиотензинпревращающего фермента (АСЕ) и rs5810761 (+9/-9) гена рецептора брадикинина 2 типа (BDKRB2) с адренореактивностью эритроцитов (АРЭ) у спортсменов и юношей, ведущих физически малоактивный образ жизни. Материалы и методы. В исследовании принял участие 61 юноша с разным уровнем двигательной активности (ДА) в возрасте 21–23 лет. Оценку АРЭ проводили по изменению скорости оседания эритроцитов (СОЭ) под действием адреналина in vitro в конечных концентрациях 10-5, 10-6, 10-7, 10-8, 10-9, 10-11, 10-13 г/мл венозной крови. По характеру наблюдаемого эффекта в соответствии с направленностью сдвигов СОЭ в присутствии адреналина мы выделили 3 типа АРЭ: антиагрегационный (АнАг), ареактивный (Ар) и агрегационный (Аг). Результаты. По результатам сравнительного и корреляционного анализа установлено, что юноши-спортсмены с генотипом +9/-9 (BDKRB2) характеризуются более высокой агрегативной устойчивостью эритроцитов к воздействию как физиологических (10-9 г/мл и ниже), так и повышенных (стрессовых) доз (выше 10-8 г/мл крови) адреналина, а также преобладанием АнАг- и Ар-типов АРЭ. У представителей разных генотипов полиморфизма I/D гена АСЕ реакция эритроцитов на адреналин не имела статистически значимых различий в группе спортсменов, тогда как в группе малоактивных студентов у лиц с генотипом D/D максимальное отклонение СОЭ при ФКА было меньше, чем при генотипе I/D. Выводы. Спортсменов, имеющих в своём генотипе аллель *-9 (+9/-9 генотип), можно считать более стрессоустойчивыми, что обеспечивается оптимальными адаптивно-компенсаторными механизмами организма, существенная роль в обеспечении которых, по-видимому, принадлежит устойчивости клеток к действию адреналина. Что касается полиморфизма гена АСЕ, то его влияние на суспензионные характеристики эритроцитов выражено слабее не только у физически малоактивных юношей, но и у спортсменов. Ключевые слова: адренореактивность эритроцитов (АРЭ), стрессоустойчивость, ген рецептора брадикинина β2 (BDKRB2), ген ангиотензинпревращающего фермента (АСЕ), двигательная активность.

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