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Critical evaluation of the colocalization between calcitonin gene-related peptide, substance P, transient receptor potential vanilloid subfamily type 1 immunoreactivities, and isolectin B4 binding in primary afferent neurons of the rat and mouse.
J Pain. 2007 Mar; 8(3):263-72.JP

Abstract

Calcitonin gene-related peptide (CGRP) and/or substance P (SP) immunoreactivity as well as isolectin B(4) (IB(4)) binding are commonly used to define peptidergic and non-peptidergic nociceptor populations, respectively. Although this demarcation is well supported in the mouse, there is accumulating evidence to suggest it is not so in the rat. Hence, this investigation was undertaken to evaluate and quantify the colocalization of the neuropeptides CGRP and SP with IB(4) binding sites and the transient receptor potential vanilloid subfamily type 1 (TRPV1) channel and to compare this colocalization between trigeminal (TG) and dorsal root ganglia (DRG) in adult rats. These findings illustrate that there is a substantial overlap (approximately 45% in the DRG and approximately 30% in the TG) between peptidergic neurons (ie, CGRP- and SP-expressing) and neurons that bind IB(4) in rat sensory ganglia. However, there were also significant differences in the colocalization of these markers between the DRG and TG. For instance, in the DRG, significantly more CGRP-immunoreactive neurons also expressed IB(4) binding sites (44.5%) compared with the TG (27.5%). In contrast, significantly fewer CGRP-immunoreactive neurons in the DRG colocalized TRPV1 immunoreactivity (49.2%) compared with the TG (70%). Moreover, we directly assessed the colocalization of CGRP and IB(4) in the TG of rats and mice using a CGRP antibody that recognizes this peptide in both species. Thus, whereas only an approximately 10% overlap was observed in TG neurons of mouse, significantly greater overlap (approximately 35%) was observed in those of rat.

PERSPECTIVE

These data indicate that in adult rat sensory ganglia, there is not a clear distinction between the peptidergic and non-peptidergic nociceptor subclasses as a function of IB(4) binding. Furthermore, there are significant differences between the TG and DRG in the degree to which commonly utilized nociceptive neuronal markers are co-expressed. Taken together, the present findings dictate prudence when extrapolating experimental conclusions about the neurochemical classification of neurons between sensory ganglia or between species, including humans.

Authors+Show Affiliations

Department of Pharmacology, The University of Texas Health Science Center at San Antonio San Antonio, TX, USA. theodore.price@mcgill.caNo affiliation info available

Pub Type(s)

Comparative Study
Evaluation Study
Journal Article
Research Support, N.I.H., Extramural

Language

eng

PubMed ID

17113352

Citation

Price, Theodore J., and Christopher M. Flores. "Critical Evaluation of the Colocalization Between Calcitonin Gene-related Peptide, Substance P, Transient Receptor Potential Vanilloid Subfamily Type 1 Immunoreactivities, and Isolectin B4 Binding in Primary Afferent Neurons of the Rat and Mouse." The Journal of Pain : Official Journal of the American Pain Society, vol. 8, no. 3, 2007, pp. 263-72.
Price TJ, Flores CM. Critical evaluation of the colocalization between calcitonin gene-related peptide, substance P, transient receptor potential vanilloid subfamily type 1 immunoreactivities, and isolectin B4 binding in primary afferent neurons of the rat and mouse. J Pain. 2007;8(3):263-72.
Price, T. J., & Flores, C. M. (2007). Critical evaluation of the colocalization between calcitonin gene-related peptide, substance P, transient receptor potential vanilloid subfamily type 1 immunoreactivities, and isolectin B4 binding in primary afferent neurons of the rat and mouse. The Journal of Pain : Official Journal of the American Pain Society, 8(3), 263-72.
Price TJ, Flores CM. Critical Evaluation of the Colocalization Between Calcitonin Gene-related Peptide, Substance P, Transient Receptor Potential Vanilloid Subfamily Type 1 Immunoreactivities, and Isolectin B4 Binding in Primary Afferent Neurons of the Rat and Mouse. J Pain. 2007;8(3):263-72. PubMed PMID: 17113352.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Critical evaluation of the colocalization between calcitonin gene-related peptide, substance P, transient receptor potential vanilloid subfamily type 1 immunoreactivities, and isolectin B4 binding in primary afferent neurons of the rat and mouse. AU - Price,Theodore J, AU - Flores,Christopher M, Y1 - 2006/11/16/ PY - 2006/03/17/received PY - 2006/08/10/revised PY - 2006/09/09/accepted PY - 2006/11/23/pubmed PY - 2007/5/23/medline PY - 2006/11/23/entrez SP - 263 EP - 72 JF - The journal of pain : official journal of the American Pain Society JO - J Pain VL - 8 IS - 3 N2 - UNLABELLED: Calcitonin gene-related peptide (CGRP) and/or substance P (SP) immunoreactivity as well as isolectin B(4) (IB(4)) binding are commonly used to define peptidergic and non-peptidergic nociceptor populations, respectively. Although this demarcation is well supported in the mouse, there is accumulating evidence to suggest it is not so in the rat. Hence, this investigation was undertaken to evaluate and quantify the colocalization of the neuropeptides CGRP and SP with IB(4) binding sites and the transient receptor potential vanilloid subfamily type 1 (TRPV1) channel and to compare this colocalization between trigeminal (TG) and dorsal root ganglia (DRG) in adult rats. These findings illustrate that there is a substantial overlap (approximately 45% in the DRG and approximately 30% in the TG) between peptidergic neurons (ie, CGRP- and SP-expressing) and neurons that bind IB(4) in rat sensory ganglia. However, there were also significant differences in the colocalization of these markers between the DRG and TG. For instance, in the DRG, significantly more CGRP-immunoreactive neurons also expressed IB(4) binding sites (44.5%) compared with the TG (27.5%). In contrast, significantly fewer CGRP-immunoreactive neurons in the DRG colocalized TRPV1 immunoreactivity (49.2%) compared with the TG (70%). Moreover, we directly assessed the colocalization of CGRP and IB(4) in the TG of rats and mice using a CGRP antibody that recognizes this peptide in both species. Thus, whereas only an approximately 10% overlap was observed in TG neurons of mouse, significantly greater overlap (approximately 35%) was observed in those of rat. PERSPECTIVE: These data indicate that in adult rat sensory ganglia, there is not a clear distinction between the peptidergic and non-peptidergic nociceptor subclasses as a function of IB(4) binding. Furthermore, there are significant differences between the TG and DRG in the degree to which commonly utilized nociceptive neuronal markers are co-expressed. Taken together, the present findings dictate prudence when extrapolating experimental conclusions about the neurochemical classification of neurons between sensory ganglia or between species, including humans. SN - 1526-5900 UR - https://www.unboundmedicine.com/medline/citation/17113352/Critical_evaluation_of_the_colocalization_between_calcitonin_gene_related_peptide_substance_P_transient_receptor_potential_vanilloid_subfamily_type_1_immunoreactivities_and_isolectin_B4_binding_in_primary_afferent_neurons_of_the_rat_and_mouse_ DB - PRIME DP - Unbound Medicine ER -