Primary sensory neuron : the international interdisciplinary journal reporting basic and clinical research on sensory receptors and primary afferent neurons最新文献
Pub Date : 1998-01-01DOI: 10.1163/092996398750132197
S. Warner, M. I. Lomax, C. Besirli, T. Gong
We used the technique of differential display of RNA to identify genes expressed in the chick auditory epithelium in response to acoustic trauma. In the course of these studies, we identified a partial cDNA (amplicon) derived from the 3 untranslated region of cRZF , a chicken gene encoding a zinc finger protein with a Cys 3 HisCys 4 (RING) motif that coordinates zinc. We identified and sequenced human RZF and mouse Rzf cDNAs encoding the mammalian homologs of cRZF . The chick, human and mouse RZF proteins each comprise 381 amino acids, 85% of which are identical in the three species. Thus, the RZF gene has been conserved throughout vertebrate evolution. We also identified a cDNA that predicts a truncated mouse Rzf protein that lacks half of the RING finger domain. The human RZF gene is located on chromosome 3q between anonymous DNA markers D3S1557 and D3S1306.
{"title":"The gene for a RING zinc finger protein is expressed in the chick inner ear after noise exposure","authors":"S. Warner, M. I. Lomax, C. Besirli, T. Gong","doi":"10.1163/092996398750132197","DOIUrl":"https://doi.org/10.1163/092996398750132197","url":null,"abstract":"We used the technique of differential display of RNA to identify genes expressed in the chick auditory epithelium in response to acoustic trauma. In the course of these studies, we identified a partial cDNA (amplicon) derived from the 3 untranslated region of cRZF , a chicken gene encoding a zinc finger protein with a Cys 3 HisCys 4 (RING) motif that coordinates zinc. We identified and sequenced human RZF and mouse Rzf cDNAs encoding the mammalian homologs of cRZF . The chick, human and mouse RZF proteins each comprise 381 amino acids, 85% of which are identical in the three species. Thus, the RZF gene has been conserved throughout vertebrate evolution. We also identified a cDNA that predicts a truncated mouse Rzf protein that lacks half of the RING finger domain. The human RZF gene is located on chromosome 3q between anonymous DNA markers D3S1557 and D3S1306.","PeriodicalId":82360,"journal":{"name":"Primary sensory neuron : the international interdisciplinary journal reporting basic and clinical research on sensory receptors and primary afferent neurons","volume":"2 1","pages":"305-315"},"PeriodicalIF":0.0,"publicationDate":"1998-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1163/092996398750132197","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"64533218","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
During embryogenesis sensory innervation is established quite precisely, but the mechanisms responsible are poorly understood. Whereas sensory neurons that supply muscle appear to require nearby motor axons to reach their target muscles, sensory neurons that supply skin do not. We have investigated the specificity with which sensory axons interact with motor axons, using the avian trigeminal sensory system, where prospective cutaneous and muscle afferents are anatomically separate. To test whether muscle afferents selectively associate with the appropriate motor axons, we co-cultured muscle afferents from the trigeminal mesencephalic nucleus with appropriate trigeminal motoneurons from rhombomeres 2/3 and with inappropriate facial motoneurons from rhombomeres 4/5. To test whether prospective cutaneous and muscle afferents can be distinguished by their interactions with motor axons, we cocultured cutaneous neurons from trigeminal ganglia with trigeminal motoneurons. Dye labeling and time-lapse videomicroscopy revealed no obvious differences between the interactions of muscle afferents with appropriate and inappropriate motor axons or between the interactions of cutaneous and muscle afferents with motor axons. Sensory axons intermixed freely with and crossed over motor axons without fasciculating, regardless of the combination of sensory and motor axons examined. These results suggest that outgrowing sensory neurons may not yet have distinct identities, raising the possibility that sensory innervation patterns are determined more by spatial or temporal constraints on axon growth than by active pathway or target selection. In contrast, motor axons often retracted upon contacting sensory afferents, indicating that there are marked differences between sensory and motor growth cones at the stages studied.
{"title":"Lack of specificity in the interactions of cranial sensory and motoneuron axons in vitro","authors":"S. A. Scott","doi":"10.1163/092996398744703","DOIUrl":"https://doi.org/10.1163/092996398744703","url":null,"abstract":"During embryogenesis sensory innervation is established quite precisely, but the mechanisms responsible are poorly understood. Whereas sensory neurons that supply muscle appear to require nearby motor axons to reach their target muscles, sensory neurons that supply skin do not. We have investigated the specificity with which sensory axons interact with motor axons, using the avian trigeminal sensory system, where prospective cutaneous and muscle afferents are anatomically separate. To test whether muscle afferents selectively associate with the appropriate motor axons, we co-cultured muscle afferents from the trigeminal mesencephalic nucleus with appropriate trigeminal motoneurons from rhombomeres 2/3 and with inappropriate facial motoneurons from rhombomeres 4/5. To test whether prospective cutaneous and muscle afferents can be distinguished by their interactions with motor axons, we cocultured cutaneous neurons from trigeminal ganglia with trigeminal motoneurons. Dye labeling and time-lapse videomicroscopy revealed no obvious differences between the interactions of muscle afferents with appropriate and inappropriate motor axons or between the interactions of cutaneous and muscle afferents with motor axons. Sensory axons intermixed freely with and crossed over motor axons without fasciculating, regardless of the combination of sensory and motor axons examined. These results suggest that outgrowing sensory neurons may not yet have distinct identities, raising the possibility that sensory innervation patterns are determined more by spatial or temporal constraints on axon growth than by active pathway or target selection. In contrast, motor axons often retracted upon contacting sensory afferents, indicating that there are marked differences between sensory and motor growth cones at the stages studied.","PeriodicalId":82360,"journal":{"name":"Primary sensory neuron : the international interdisciplinary journal reporting basic and clinical research on sensory receptors and primary afferent neurons","volume":"3 1","pages":"11-29"},"PeriodicalIF":0.0,"publicationDate":"1998-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1163/092996398744703","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"64533414","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1997-01-01DOI: 10.1163/092996397750131900
H. Zhong, C. Nurse
Regulation of carotid body chemoafferent discharge in mammals plays an important role in the reflex control of ventilation. A non-selective blocker (cesium) of the inward rectifier is known to inhibit carotid body afferent discharge during hypoxia, but the underlying current in corresponding neurons of the petrosal ganglia has not been characterized. In this study we provide a detailed description of a voltage-dependent, inwardly rectifying, cation non-selective current, I h , that was present in around 78% of cultured rat petrosal neurons. Activation of this current appeared to be the basis of the slowly developing depolarizing sag that was recorded under current clamp during application of hyperpolarizing current pulses. Under voltage clamp, I h was activated at voltages negative to -60 mV and had an estimated reversal potential (E h ) of about -33.1±3.4 mV (n=20). Raising extracellular [ K + ] o caused a progressive increase in I h and a positive shift in E h , whereas reducing extracellular [Na + ] o caused a small reduction in I h and an opposite shift in E h . Reducing extracellular [Cl - ] o had no significant effect on E h , though the amplitude of I h decreased. Tail current analysis revealed that the activation curve for I h was well fitted by the Boltzmann distribution, with V 1/2 =-90.6±2.2 mV (mean ± SEM; n=17) and slope factor k=10.8±0.5. I h activated more rapidly at larger hyperpolarizations; elevated [ K + ] o or lowered [Na + ] o increased the time constant (τ) of I h activation. The time constant of deactivation of I h at -60 mV was 317.1±31.9 ms (n=7). Extracellular cesium (10 mM) almost completely blocked I h , whereas barium suppressed I h by around 50%, at a similar concentration. These results, combined with the known sensitivity of the hypoxic afferent discharge to extracellular cesium, suggest that I h likely plays an important physiological role during carotid body chemosensory signaling.
{"title":"Characterization of a hyperpolarization-activated inward current in rat chemosensory petrosal neurons in vitro","authors":"H. Zhong, C. Nurse","doi":"10.1163/092996397750131900","DOIUrl":"https://doi.org/10.1163/092996397750131900","url":null,"abstract":"Regulation of carotid body chemoafferent discharge in mammals plays an important role in the reflex control of ventilation. A non-selective blocker (cesium) of the inward rectifier is known to inhibit carotid body afferent discharge during hypoxia, but the underlying current in corresponding neurons of the petrosal ganglia has not been characterized. In this study we provide a detailed description of a voltage-dependent, inwardly rectifying, cation non-selective current, I h , that was present in around 78% of cultured rat petrosal neurons. Activation of this current appeared to be the basis of the slowly developing depolarizing sag that was recorded under current clamp during application of hyperpolarizing current pulses. Under voltage clamp, I h was activated at voltages negative to -60 mV and had an estimated reversal potential (E h ) of about -33.1±3.4 mV (n=20). Raising extracellular [ K + ] o caused a progressive increase in I h and a positive shift in E h , whereas reducing extracellular [Na + ] o caused a small reduction in I h and an opposite shift in E h . Reducing extracellular [Cl - ] o had no significant effect on E h , though the amplitude of I h decreased. Tail current analysis revealed that the activation curve for I h was well fitted by the Boltzmann distribution, with V 1/2 =-90.6±2.2 mV (mean ± SEM; n=17) and slope factor k=10.8±0.5. I h activated more rapidly at larger hyperpolarizations; elevated [ K + ] o or lowered [Na + ] o increased the time constant (τ) of I h activation. The time constant of deactivation of I h at -60 mV was 317.1±31.9 ms (n=7). Extracellular cesium (10 mM) almost completely blocked I h , whereas barium suppressed I h by around 50%, at a similar concentration. These results, combined with the known sensitivity of the hypoxic afferent discharge to extracellular cesium, suggest that I h likely plays an important physiological role during carotid body chemosensory signaling.","PeriodicalId":82360,"journal":{"name":"Primary sensory neuron : the international interdisciplinary journal reporting basic and clinical research on sensory receptors and primary afferent neurons","volume":"2 1","pages":"95-110"},"PeriodicalIF":0.0,"publicationDate":"1997-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1163/092996397750131900","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"64533569","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1997-01-01DOI: 10.1163/092996397750131874
I. Nagy, P. Szucs, L. Urbán, E. Polgár, J. Croxford, A. Dray
UV irradiation evoked thermal and mechanical hypersensitivity in the glabrous skin of the rat hind paw. During the period of hyperalgesia skin samples were taken from irradiated areas of the skin and the corresponding segments of the spinal cord, and the expression of growth-associated protein 43 (GAP-43) was quantitatively measured. Although GAP-43 was present in a small number of fibers in the skin of control animals, the total length of GAP-43 positive fibers per unit area was significantly increased within 3 days after irradiation in both ipsi- and contralateral hind limbs. The time course of GAP-43 expression corresponded to that of mechanical hyperalgesia. GAP-43 immunopositivity was at its maximum on day 3 after UV irradiation and declined to control level at day 14. Increased GAP-43 immunoreactivity was similar in both hind paws except on day 3 when it was significantly more on the ipsilateral side. Most GAP-43-positive fibers were arborizing branches in the skin, but strong positivity was found around blood vessels and around sweat glands. Glyoxylic acid-induced fluorescent-catecholamine marking was associated with blood vessels without extravascular sprouting in control or UV-irradiated skin. At 3 and 5 days after UV irradiation GAP-43-positive profiles were present in the spinal L4-5 segments. GAP-43 immunoreactivity was detected on both sides in the dorsal horn with greater intensity on the ipsilateral side. We conclude that the increased expression of GAP-43 in neuronal processes of the ipsi- and contralateral paw after UV irradiation is most unlikely to be directly associated with nerve sprouting. GAP-43 expression occurred mainly in sensory fibers.
{"title":"GAP-43 immunoreactivity is enhanced after UV irradiation in the peripheral nervous system of the rat","authors":"I. Nagy, P. Szucs, L. Urbán, E. Polgár, J. Croxford, A. Dray","doi":"10.1163/092996397750131874","DOIUrl":"https://doi.org/10.1163/092996397750131874","url":null,"abstract":"UV irradiation evoked thermal and mechanical hypersensitivity in the glabrous skin of the rat hind paw. During the period of hyperalgesia skin samples were taken from irradiated areas of the skin and the corresponding segments of the spinal cord, and the expression of growth-associated protein 43 (GAP-43) was quantitatively measured. Although GAP-43 was present in a small number of fibers in the skin of control animals, the total length of GAP-43 positive fibers per unit area was significantly increased within 3 days after irradiation in both ipsi- and contralateral hind limbs. The time course of GAP-43 expression corresponded to that of mechanical hyperalgesia. GAP-43 immunopositivity was at its maximum on day 3 after UV irradiation and declined to control level at day 14. Increased GAP-43 immunoreactivity was similar in both hind paws except on day 3 when it was significantly more on the ipsilateral side. Most GAP-43-positive fibers were arborizing branches in the skin, but strong positivity was found around blood vessels and around sweat glands. Glyoxylic acid-induced fluorescent-catecholamine marking was associated with blood vessels without extravascular sprouting in control or UV-irradiated skin. At 3 and 5 days after UV irradiation GAP-43-positive profiles were present in the spinal L4-5 segments. GAP-43 immunoreactivity was detected on both sides in the dorsal horn with greater intensity on the ipsilateral side. We conclude that the increased expression of GAP-43 in neuronal processes of the ipsi- and contralateral paw after UV irradiation is most unlikely to be directly associated with nerve sprouting. GAP-43 expression occurred mainly in sensory fibers.","PeriodicalId":82360,"journal":{"name":"Primary sensory neuron : the international interdisciplinary journal reporting basic and clinical research on sensory receptors and primary afferent neurons","volume":"2 1","pages":"43-63"},"PeriodicalIF":0.0,"publicationDate":"1997-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1163/092996397750131874","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"64533076","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1997-01-01DOI: 10.1163/092996397750131973
L. Kolosova, O. V. Riabchikova, A. Moisseeva
The effect of the systemically active inhibitor of enkephalin degrading enzymes (RB 101) on functional recovery of the rat sciatic nerve after transection and microsurgical suture was examined. Using the method of registration of compound action potentials (CAPs), the dose-dependent effect of RB 101 on regenerative processes in the nerve had been revealed. Both stimulating (at 100 μ g/kg and 1 mg/kg) and inhibitory (at 10 mg/kg) effects of RB 101 on the growth of regenerating nerve fibers were found after 20 days of surgical procedure. The role of opioids in the regulation of regenerative processes in peripheral nerves is discussed.
{"title":"The effect of enkephalin degrading enzymes inhibitor RB 101 on functional recovery of injured sciatic nerve of the rat","authors":"L. Kolosova, O. V. Riabchikova, A. Moisseeva","doi":"10.1163/092996397750131973","DOIUrl":"https://doi.org/10.1163/092996397750131973","url":null,"abstract":"The effect of the systemically active inhibitor of enkephalin degrading enzymes (RB 101) on functional recovery of the rat sciatic nerve after transection and microsurgical suture was examined. Using the method of registration of compound action potentials (CAPs), the dose-dependent effect of RB 101 on regenerative processes in the nerve had been revealed. Both stimulating (at 100 μ g/kg and 1 mg/kg) and inhibitory (at 10 mg/kg) effects of RB 101 on the growth of regenerating nerve fibers were found after 20 days of surgical procedure. The role of opioids in the regulation of regenerative processes in peripheral nerves is discussed.","PeriodicalId":82360,"journal":{"name":"Primary sensory neuron : the international interdisciplinary journal reporting basic and clinical research on sensory receptors and primary afferent neurons","volume":"2 1","pages":"185-190"},"PeriodicalIF":0.0,"publicationDate":"1997-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1163/092996397750131973","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"64533300","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1997-01-01DOI: 10.1163/092996397750131982
V. Khavinson, V. B. Okulov, N. Chalisova
The effect of natural brain peptides (cortexin and epithalamin) as well as synthetic tetrapeptides (brain peptide and epiphysis peptide) were investigated in organotypic cultures of dorsal root ganglion (DRG) neurons and explants of brain tissue from 10-11 day old chick embryos. Cortexin (2-100 ng/ml), epithalamin (200 ng/ml), brain peptide (2 ng/ml) and epiphysis peptide (20 ng/ml) showed a neurite-stimulating effect in DRG cultures as compared to the control explants. Cortexin at 100 ng/ml and brain peptide at 20 ng/ml showed a stimulating effect in cortical cultures, and epithalamin at 200 ng/ml and epiphysis peptide at 100 ng/ml showed a stimulating effect in cultures of subcortical structures as compared to the control explants.
{"title":"The neurite-stimulating effect of peptides from brain in dorsal root ganglion neuron organotypic culture","authors":"V. Khavinson, V. B. Okulov, N. Chalisova","doi":"10.1163/092996397750131982","DOIUrl":"https://doi.org/10.1163/092996397750131982","url":null,"abstract":"The effect of natural brain peptides (cortexin and epithalamin) as well as synthetic tetrapeptides (brain peptide and epiphysis peptide) were investigated in organotypic cultures of dorsal root ganglion (DRG) neurons and explants of brain tissue from 10-11 day old chick embryos. Cortexin (2-100 ng/ml), epithalamin (200 ng/ml), brain peptide (2 ng/ml) and epiphysis peptide (20 ng/ml) showed a neurite-stimulating effect in DRG cultures as compared to the control explants. Cortexin at 100 ng/ml and brain peptide at 20 ng/ml showed a stimulating effect in cortical cultures, and epithalamin at 200 ng/ml and epiphysis peptide at 100 ng/ml showed a stimulating effect in cultures of subcortical structures as compared to the control explants.","PeriodicalId":82360,"journal":{"name":"Primary sensory neuron : the international interdisciplinary journal reporting basic and clinical research on sensory receptors and primary afferent neurons","volume":"2 1","pages":"191-200"},"PeriodicalIF":0.0,"publicationDate":"1997-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1163/092996397750131982","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"64533350","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1997-01-01DOI: 10.1163/092996397750131838
R. Peters, D. Kraaij, F. Bretschneider
We compared the functioning of catfish electroreceptors in vivo and in vitro by recording the resting discharge and the sensitivity of organs before and immediately after skin patch excision. The in vitro preparation functions for several hours and can be used to assess synaptic functioning and other aspects of sensory transduction. However, both the sensitivity and the resting discharge rate are lower in vitro than in vivo. The sensitivity reduction can be caused by shunting of the stimulus current in the recording chamber, but the reduction of the spontaneous activity cannot. This is most likely due to hypoxia in the excised skin patch. In addition, interspike interval histograms showed mild anomalies in the firing pattern in vitro, as indicated by the parameters λ and r of fitted Γ distributions. We conclude that (i) in vitro recording is best suited for neuropharmacological research, and (ii) in vivo recording is better suited for long-term studies and analyses of stochastical spike processes.
{"title":"Comparison of electroreceptor organ functioning in vivo and in vitro","authors":"R. Peters, D. Kraaij, F. Bretschneider","doi":"10.1163/092996397750131838","DOIUrl":"https://doi.org/10.1163/092996397750131838","url":null,"abstract":"We compared the functioning of catfish electroreceptors in vivo and in vitro by recording the resting discharge and the sensitivity of organs before and immediately after skin patch excision. The in vitro preparation functions for several hours and can be used to assess synaptic functioning and other aspects of sensory transduction. However, both the sensitivity and the resting discharge rate are lower in vitro than in vivo. The sensitivity reduction can be caused by shunting of the stimulus current in the recording chamber, but the reduction of the spontaneous activity cannot. This is most likely due to hypoxia in the excised skin patch. In addition, interspike interval histograms showed mild anomalies in the firing pattern in vitro, as indicated by the parameters λ and r of fitted Γ distributions. We conclude that (i) in vitro recording is best suited for neuropharmacological research, and (ii) in vivo recording is better suited for long-term studies and analyses of stochastical spike processes.","PeriodicalId":82360,"journal":{"name":"Primary sensory neuron : the international interdisciplinary journal reporting basic and clinical research on sensory receptors and primary afferent neurons","volume":"2 1","pages":"1-8"},"PeriodicalIF":0.0,"publicationDate":"1997-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1163/092996397750131838","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"64533009","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1997-01-01DOI: 10.1163/092996397750131847
D. Ganchrow, G. Pelled, J. Ganchrow
This autoradiographic study in the chick embryo tested whether one possible source of cells comprising early-developing taste bud primordia arose from gemmal cell precursors, or their progeny, born during the first week of incubation. Following single in ovo injections of [ 3 H]thymidine on embryonic day (E) 2, E4 or E6, labeled gemmal cells were identified in developing, anterior lower beak taste buds on E19, which is 2 days after the first sign of bud primordium formation and 2 days before hatching. The greatest number of labeled cells/bud occurred after the E2 injection. Thus the embryonic gustatory peripheral receptor, in common with developing auditory, vestibular and retinal sensory receptor epithelia, contains at least postmitotic and/or quiescent cells whose precursors proliferated during the first week of gestation. These early pre-bud precursors could serve as tropic targets for local epithelial cells in the formation of bud primordia as well as guiding growing distal processes of the gustatory sensory ganglia whose neurons are already postmitotic by E5.
{"title":"Early embryonic birth of gemmal cells in the prehatching chick","authors":"D. Ganchrow, G. Pelled, J. Ganchrow","doi":"10.1163/092996397750131847","DOIUrl":"https://doi.org/10.1163/092996397750131847","url":null,"abstract":"This autoradiographic study in the chick embryo tested whether one possible source of cells comprising early-developing taste bud primordia arose from gemmal cell precursors, or their progeny, born during the first week of incubation. Following single in ovo injections of [ 3 H]thymidine on embryonic day (E) 2, E4 or E6, labeled gemmal cells were identified in developing, anterior lower beak taste buds on E19, which is 2 days after the first sign of bud primordium formation and 2 days before hatching. The greatest number of labeled cells/bud occurred after the E2 injection. Thus the embryonic gustatory peripheral receptor, in common with developing auditory, vestibular and retinal sensory receptor epithelia, contains at least postmitotic and/or quiescent cells whose precursors proliferated during the first week of gestation. These early pre-bud precursors could serve as tropic targets for local epithelial cells in the formation of bud primordia as well as guiding growing distal processes of the gustatory sensory ganglia whose neurons are already postmitotic by E5.","PeriodicalId":82360,"journal":{"name":"Primary sensory neuron : the international interdisciplinary journal reporting basic and clinical research on sensory receptors and primary afferent neurons","volume":"2 1","pages":"9-19"},"PeriodicalIF":0.0,"publicationDate":"1997-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1163/092996397750131847","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"64533017","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1997-01-01DOI: 10.1163/092996397750131946
P. Sántha, F. Domoki, A. Juhász, M. Dux, G. Jancsó
A particular group of mammalian primary afferent neurons involved in nociception is characterized by its specific sensitivity to capsaicin, the pungent principle of red pepper. A striking manifestation of neuronal capsaicin sensitivity is the degeneration of a morphologically well characterized population of sensory ganglion cells following a systemic injection of this compound. The present study demonstrated that prior transection of the peripheral axons of these neurons protects them from the neurotoxic action of systemically administered capsaicin. It is suggested that this phenomenon is related to an impairment of axon transport mechanisms. It is concluded that maintenance of capsaicin sensitivity is critically dependent on the integrity of the peripheral branch of the primary sensory neuron and peripherally derived trophic factor(s) may profoundly influence the functional traits of sensory ganglion cells.
{"title":"Axotomy prevents capsaicin-induced sensory ganglion cell degeneration","authors":"P. Sántha, F. Domoki, A. Juhász, M. Dux, G. Jancsó","doi":"10.1163/092996397750131946","DOIUrl":"https://doi.org/10.1163/092996397750131946","url":null,"abstract":"A particular group of mammalian primary afferent neurons involved in nociception is characterized by its specific sensitivity to capsaicin, the pungent principle of red pepper. A striking manifestation of neuronal capsaicin sensitivity is the degeneration of a morphologically well characterized population of sensory ganglion cells following a systemic injection of this compound. The present study demonstrated that prior transection of the peripheral axons of these neurons protects them from the neurotoxic action of systemically administered capsaicin. It is suggested that this phenomenon is related to an impairment of axon transport mechanisms. It is concluded that maintenance of capsaicin sensitivity is critically dependent on the integrity of the peripheral branch of the primary sensory neuron and peripherally derived trophic factor(s) may profoundly influence the functional traits of sensory ganglion cells.","PeriodicalId":82360,"journal":{"name":"Primary sensory neuron : the international interdisciplinary journal reporting basic and clinical research on sensory receptors and primary afferent neurons","volume":"2 1","pages":"159-165"},"PeriodicalIF":0.0,"publicationDate":"1997-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1163/092996397750131946","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"64533186","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1997-01-01DOI: 10.1163/092996397750131856
H. Martin
Alternative non-histaminergic mechanisms of pruritus involve interleukins and opioid peptides. Opioid peptides are released from dermal immunocytes upon interleukin activation. Although opioid receptor antagonists have been found to reduce intractable pruritus resistant to antihistamines, it is not clear whether opioid peptides can selectively activate nociceptive nerve endings to produce pruritus, in addition to their degranulator effects on mast cells and their desensitizing effects to noxious mechanical and thermal stimuli on nociceptors. Therefore, the present study was aimed at determining activating effects of opioid peptides, including β-endorphin, dynorphin A and Met-enkephalin, on physiologically identified cutaneous receptors. One-third of C-fiber polymodal receptors were activated by these opioid peptides and responses were characterized by a potent tachyphylaxis. Concentration thresholds ranged from 0.1 to 1 μM and latencies from 11 to 25 s (16±8 s). Response magnitudes varied considerably from one unit to another and generally did not increase at concentration above 10 μM. These units were also activated and/or sensitized by subsequent intradermal injection of bradykinin, which counteracted the opioid peptides-induced desensitization to mechanical and thermal stimuli. In conclusion, endogenous opioid peptides are pruritogenic inflammatory mediators, when activating one-third of cutaneous C-fiber polymodal receptors that are not chemically desensitized by them.
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Primary sensory neuron : the international interdisciplinary journal reporting basic and clinical research on sensory receptors and primary afferent neurons
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