HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) All Versions of this Article: 93/3/1358    most recent 00591.2004v1 Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in ISI Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via ISI Web of Science (8) Citing Articles via Google Scholar Google Scholar Articles by Rau, K. K. Articles by Cooper, B. Y. Search for Related Content PubMed PubMed Citation Articles by Rau, K. K. Articles by Cooper, B. Y.

Nicotinic AChR in Subclassified Capsaicin-Sensitive and -Insensitive Nociceptors of the Rat DRG

¹Department of Oral Surgery and Diagnostic Sciences, Division of Neurosciences, College of Dentistry, ²Department of Physiological Sciences, College of Veterinary Medicine, and ³Department of Neuroscience, College of Medicine and University of Florida McKnight Brain Institute, Gainesville, Florida

Submitted 8 June 2004; accepted in final form 4 October 2004

Nociceptive cells of the dorsal root ganglion (DRG) were subclassified, in vitro, according to patterns of voltage-activated currents. The distribution and form of nicotinic ACh receptors (nAChRs) were determined. nAChRs were present on both capsaicin-sensitive and -insensitive nociceptors but were not universally present in unmyelinated nociceptors. In contrast, all A nociceptors (types 4, 6, and 9) expressed slowly decaying nAChR. Three major forms of nicotinic currents were identified. Specific agonists and antagonists were used to demonstrate the presence of ₇ in two classes of capsaicin-sensitive, unmyelinated nociceptors (types 2 and 8). In type 2 cells, ₇-mediated currents were found in isolation. Whereas ₇ was co-expressed with other nAChR in type 8 cells. These were the only classes in which ₇ was identified. Other nociceptive classes expressed slowly decaying currents with ₄ pharmacology. Based on concentration response curves formed by nicotinic agonists [ACh, nicotine, dimethyl phenyl piperazinium (DMPP), cytisine] evidence emerged of two distinct nAChR differentially expressed in type 4 (₃₄) and types 5 and 8 (_{34 5}). Although identification could not be made with absolute certainty, patterns of potency (type 4: DMPP > cytisine > nicotine = ACh; type 5 and type 8: DMPP = cytisine > nicotine = ACh) and efficacy provided strong support for the presence of two distinct channels based on an ₃₄ platform. Studies conducted on one nonnociceptive class (type 3) failed to reveal any nAChR. After multiple injections of Di-I (1,1'-dilinoleyl-3,3,3',3'-tetramethylindocarbocyanine perchlorate) into the hairy skin of the hindlimb, we identified cell types 2, 4, 6, 8, and 9 as skin nociceptors that expressed nicotinic receptors. We conclude that at least three nicotinic AChR are diversely distributed into discrete subclasses of nociceptors that innervate hairy skin.

This article has been cited by other articles:

				K. K. Rau, N. Jiang, R. D. Johnson, and B. Y. Cooper Heat Sensitization in Skin and Muscle Nociceptors Expressing Distinct Combinations of TRPV1 and TRPV2 Protein J Neurophysiol, April 1, 2007; 97(4): 2651 - 2662. [Abstract] [Full Text] [PDF]

				N. Jiang, K. K. Rau, R. D. Johnson, and B. Y. Cooper Proton Sensitivity Ca2+ Permeability and Molecular Basis of Acid-Sensing Ion Channels Expressed in Glabrous and Hairy Skin Afferents J Neurophysiol, April 1, 2006; 95(4): 2466 - 2478. [Abstract] [Full Text] [PDF]

				S. Fucile, A. Sucapane, and F. Eusebi Ca2+ permeability of nicotinic acetylcholine receptors from rat dorsal root ganglion neurones J. Physiol., May 15, 2005; 565(1): 219 - 228. [Abstract] [Full Text] [PDF]