title: Three-dimensional architectures of P2X2-/P2X3-immunoreactive afferent nerve terminals in the rat carotid body as revealed by confocal laser scanning microscopy.
abstract: We investigated the three-dimensional architectures of P2X2-/P2X3-immunoreactive nerve terminals in the rat carotid body using immunohistochemistry with confocal laser microscopy. Nerve endings immunoreactive for P2X2 and P2X3 were associated with clusters of type I cells, whereas some nerve endings were sparsely distributed in a few clusters. Most nerve endings surrounding type I cells were hederiform in shape and extended several flattened axon terminals, which were polygonal or pleomorphic in shape and contained P2X2-/P2X3-immunoreactive products. Three-dimensional reconstruction views revealed that some flattened nerve endings with P2X3 immunoreactivity formed arborized, sac- or goblet-like terminal structures and were attached to type I cells immunoreactive for tyrosine hydroxylase (TH). However, P2X3-immunoreactive axon terminals were sparsely distributed in type I cells immunoreactive for dopamine beta-hydroxylase. Multi-immunolabeling for P2X2, S100, and TH revealed that P2X2-immunoreactive axon terminals were attached to TH-immunoreactive type I cells on the inside of type II cells with S100 immunoreactivity. These results revealed the detailed morphology of P2X2-/P2X3-immunoreactive nerve terminals and suggest that sensory nerve endings may integrate chemosensory signals from clustered type I cells with their variform nerve terminals.
authors.affiliation: Department of Anatomy (Cell Biology), Iwate Medical University, Yahaba, Japan.
authors.forename: Takuya
authors.initials: T
authors.lastname: Yokoyama
authors.affiliation: Department of Anatomy (Cell Biology), Iwate Medical University, Yahaba, Japan.
authors.forename: Tomoyuki
authors.initials: T
authors.lastname: Saino
authors.affiliation: Laboratory of Veterinary Anatomy and Cell Biology, Faculty of Agriculture, Iwate University, 18-8 Ueda 3-chome, Morioka, Iwate, 020-8550, Japan.
authors.forename: Nobuaki
authors.initials: N
authors.lastname: Nakamuta
authors.affiliation: Laboratory for Anatomy and Physiology, Department of Sport and Medical Science, Kokushikan University, Tama, Japan.
authors.forename: Tatsumi
authors.initials: T
authors.lastname: Kusakabe
authors.affiliation: Laboratory of Veterinary Anatomy and Cell Biology, Faculty of Agriculture, Iwate University, 18-8 Ueda 3-chome, Morioka, Iwate, 020-8550, Japan. yyoshio@iwate-u.ac.jp.
authors.forename: Yoshio
authors.initials: Y
authors.lastname: Yamamoto
mesh_terms: D000818:Animals; D002344:Carotid Body / Q000033:anatomy & histology* / Q000276:immunology / Q000378:metabolism*; D007150:Immunohistochemistry; D008297:Male; D018613:Microscopy, Confocal; D009411:Nerve Endings / Q000276:immunology / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D058476:Receptors, Purinergic P2X2 / Q000032:analysis / Q000276:immunology*; D058477:Receptors, Purinergic P2X3 / Q000032:analysis / Q000276:immunology*
chemical_list: D058476:Receptors, Purinergic P2X2; D058477:Receptors, Purinergic P2X3
keywords: Afferent nerve terminal; Carotid body; Immunohistochemistry; P2X purinoreceptor; Type I cells