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Comparison of intracellular calcium signals evoked by heat and capsaicin in cultured rat dorsal root ganglion neurons and in a cell line expressing the rat vanilloid receptor, VR1.
Neuroscience. 2001; 102(1):177-84.N

Abstract

The cloning of the receptor for capsaicin, vanilloid receptor 1, has shown it to be non-selective cation channel with a high calcium permeability which can be opened by noxious heat as well as capsaicin. Here we compare the calcium signals produced by native and recombinant capsaicin receptors when activated by either heat or capsaicin by imaging intracellular calcium levels ([Ca2+](i)) in rat dorsal root ganglion neurons and Chinese hamster ovary cells transfected with the rat vanilloid receptor, vanilloid receptor 1. Vanilloid receptor 1 transfected cells and a subset of dorsal root ganglion neurons responded to both capsaicin and to heating to 50 degrees C with rapid, substantial and reversible rises in [Ca2+](i). All except one of the dorsal root ganglion neurons responsive to capsaicin also showed sensitivity to heat, and most, but not all, heat-sensitive neurons also responded to capsaicin. Both capsaicin and heat responses were dependent on the presence of extracellular Ca2+. Non-transfected Chinese hamster ovary cells and non-responsive dorsal root ganglion neurons showed only small rises in [Ca2+](i) in response to heat which did not depend on the presence of external Ca2+. Responsive dorsal root ganglion neurons and vanilloid receptor 1 transfected cells showed a clear temperature threshold, above which [Ca2+](i) increased rapidly. This was estimated to be 42.6+/-0.3 degrees C for vanilloid receptor 1 transfected cells and 42.0+/-0.6 degrees C for dorsal root ganglion neurons. The competitive capsaicin antagonist capsazepine (10microM) abolished [Ca2+](i) increases stimulated by capsaicin in both dorsal root ganglion neurons and vanilloid receptor 1 transfected cells. However, responses to heat of a similar magnitude in the same cells were inhibited by only 37% by capsazepine (10microM). In vanilloid receptor 1 transfected cells, Ruthenium Red (10microM) blocked responses to both capsaicin and heat. These results demonstrate that imaging of [Ca2+](i) can identify dorsal root ganglion neurons which are responsive to both heat and capsaicin. They show that heat and capsaicin responses mediated by native and recombinant capsaicin receptors are similar with respect to the characteristics and pharmacology examined, suggesting that expression of recombinant vanilloid receptor 1 in cell lines accurately reproduces the properties of the native receptor.

Authors+Show Affiliations

Novartis Institute for Medical Sciences, 5 Gower Place, WC1E 6BN, London, UK.No affiliation info availableNo affiliation info available

Pub Type(s)

Comparative Study
Journal Article

Language

eng

PubMed ID

11226681

Citation

Savidge, J R., et al. "Comparison of Intracellular Calcium Signals Evoked By Heat and Capsaicin in Cultured Rat Dorsal Root Ganglion Neurons and in a Cell Line Expressing the Rat Vanilloid Receptor, VR1." Neuroscience, vol. 102, no. 1, 2001, pp. 177-84.
Savidge JR, Ranasinghe SP, Rang HP. Comparison of intracellular calcium signals evoked by heat and capsaicin in cultured rat dorsal root ganglion neurons and in a cell line expressing the rat vanilloid receptor, VR1. Neuroscience. 2001;102(1):177-84.
Savidge, J. R., Ranasinghe, S. P., & Rang, H. P. (2001). Comparison of intracellular calcium signals evoked by heat and capsaicin in cultured rat dorsal root ganglion neurons and in a cell line expressing the rat vanilloid receptor, VR1. Neuroscience, 102(1), 177-84.
Savidge JR, Ranasinghe SP, Rang HP. Comparison of Intracellular Calcium Signals Evoked By Heat and Capsaicin in Cultured Rat Dorsal Root Ganglion Neurons and in a Cell Line Expressing the Rat Vanilloid Receptor, VR1. Neuroscience. 2001;102(1):177-84. PubMed PMID: 11226681.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Comparison of intracellular calcium signals evoked by heat and capsaicin in cultured rat dorsal root ganglion neurons and in a cell line expressing the rat vanilloid receptor, VR1. AU - Savidge,J R, AU - Ranasinghe,S P, AU - Rang,H P, PY - 2001/2/28/pubmed PY - 2001/5/22/medline PY - 2001/2/28/entrez SP - 177 EP - 84 JF - Neuroscience JO - Neuroscience VL - 102 IS - 1 N2 - The cloning of the receptor for capsaicin, vanilloid receptor 1, has shown it to be non-selective cation channel with a high calcium permeability which can be opened by noxious heat as well as capsaicin. Here we compare the calcium signals produced by native and recombinant capsaicin receptors when activated by either heat or capsaicin by imaging intracellular calcium levels ([Ca2+](i)) in rat dorsal root ganglion neurons and Chinese hamster ovary cells transfected with the rat vanilloid receptor, vanilloid receptor 1. Vanilloid receptor 1 transfected cells and a subset of dorsal root ganglion neurons responded to both capsaicin and to heating to 50 degrees C with rapid, substantial and reversible rises in [Ca2+](i). All except one of the dorsal root ganglion neurons responsive to capsaicin also showed sensitivity to heat, and most, but not all, heat-sensitive neurons also responded to capsaicin. Both capsaicin and heat responses were dependent on the presence of extracellular Ca2+. Non-transfected Chinese hamster ovary cells and non-responsive dorsal root ganglion neurons showed only small rises in [Ca2+](i) in response to heat which did not depend on the presence of external Ca2+. Responsive dorsal root ganglion neurons and vanilloid receptor 1 transfected cells showed a clear temperature threshold, above which [Ca2+](i) increased rapidly. This was estimated to be 42.6+/-0.3 degrees C for vanilloid receptor 1 transfected cells and 42.0+/-0.6 degrees C for dorsal root ganglion neurons. The competitive capsaicin antagonist capsazepine (10microM) abolished [Ca2+](i) increases stimulated by capsaicin in both dorsal root ganglion neurons and vanilloid receptor 1 transfected cells. However, responses to heat of a similar magnitude in the same cells were inhibited by only 37% by capsazepine (10microM). In vanilloid receptor 1 transfected cells, Ruthenium Red (10microM) blocked responses to both capsaicin and heat. These results demonstrate that imaging of [Ca2+](i) can identify dorsal root ganglion neurons which are responsive to both heat and capsaicin. They show that heat and capsaicin responses mediated by native and recombinant capsaicin receptors are similar with respect to the characteristics and pharmacology examined, suggesting that expression of recombinant vanilloid receptor 1 in cell lines accurately reproduces the properties of the native receptor. SN - 0306-4522 UR - https://www.unboundmedicine.com/medline/citation/11226681/Comparison_of_intracellular_calcium_signals_evoked_by_heat_and_capsaicin_in_cultured_rat_dorsal_root_ganglion_neurons_and_in_a_cell_line_expressing_the_rat_vanilloid_receptor_VR1_ L2 - https://linkinghub.elsevier.com/retrieve/pii/S0306-4522(00)00447-4 DB - PRIME DP - Unbound Medicine ER -