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Inflammation of peripheral tissues and injury to peripheral nerves induce differing effects in the expression of the calcium‐sensitive N‐arachydonoylethanolamine‐synthesizing enzyme and related molecules in rat primary sensory neurons
Author(s) -
SousaValente João,
Varga Angelika,
TorresPerez Jose Vicente,
Jenes Agnes,
Wahba John,
Mackie Ken,
Cravatt Benjamin,
Ueda Natsuo,
Tsuboi Kazuhito,
Santha Peter,
Jancso Gabor,
Tailor Hiren,
Avelino António,
Nagy Istvan
Publication year - 2017
Publication title -
journal of comparative neurology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.855
H-Index - 209
eISSN - 1096-9861
pISSN - 0021-9967
DOI - 10.1002/cne.24154
Subject(s) - anandamide , trpv1 , endocannabinoid system , cannabinoid receptor , biology , fatty acid amide hydrolase , transient receptor potential channel , cannabinoid , autocrine signalling , sensory neuron , sensory system , neuroscience , receptor , microbiology and biotechnology , biochemistry , agonist
Abstract Elevation of intracellular Ca 2+ concentration induces the synthesis of N‐arachydonoylethanolamine (anandamide) in a subpopulation of primary sensory neurons. N‐acylphosphatidylethanolamine phospholipase D (NAPE‐PLD) is the only known enzyme that synthesizes anandamide in a Ca 2+ ‐dependent manner. NAPE‐PLD mRNA as well as anandamide's main targets, the excitatory transient receptor potential vanilloid type 1 ion channel (TRPV1), the inhibitory cannabinoid type 1 (CB1) receptor, and the main anandamide‐hydrolyzing enzyme fatty acid amide hydrolase (FAAH), are all expressed by subpopulations of nociceptive primary sensory neurons. Thus, NAPE‐PLD, TRPV1, the CB1 receptor, and FAAH could form an autocrine signaling system that could shape the activity of a major subpopulation of nociceptive primary sensory neurons, contributing to the development of pain. Although the expression patterns of TRPV1, the CB1 receptor, and FAAH have been comprehensively elucidated, little is known about NAPE‐PLD expression in primary sensory neurons under physiological and pathological conditions. This study shows that NAPE‐PLD is expressed by about one‐third of primary sensory neurons, the overwhelming majority of which also express nociceptive markers as well as the CB1 receptor, TRPV1, and FAAH. Inflammation of peripheral tissues and injury to peripheral nerves induce differing but concerted changes in the expression pattern of NAPE‐PLD, the CB1 receptor, TRPV1, and FAAH. Together these data indicate the existence of the anatomical basis for an autocrine signaling system in a major proportion of nociceptive primary sensory neurons and that alterations in that autocrine signaling by peripheral pathologies could contribute to the development of both inflammatory and neuropathic pain.