title: Glutaminase Increases in Rat Dorsal Root Ganglion Neurons after Unilateral Adjuvant-Induced Hind Paw Inflammation.
abstract: Glutamate is a neurotransmitter used at both the peripheral and central terminals of nociceptive primary sensory neurons, yet little is known concerning regulation of glutamate metabolism during peripheral inflammation. Glutaminase (GLS) is an enzyme of the glutamate-glutamine cycle that converts glutamine into glutamate for neurotransmission and is implicated in producing elevated levels of glutamate in central and peripheral terminals. A potential mechanism for increased levels of glutamate is an elevation in GLS expression. We assessed GLS expression after unilateral hind paw inflammation by measuring GLS immunoreactivity (ir) with quantitative image analysis of L4 dorsal root ganglion (DRG) neurons after one, two, four, and eight days of adjuvant-induced arthritis (AIA) compared to saline injected controls. No significant elevation in GLS-ir occurred in the DRG ipsilateral to the inflamed hind paw after one or two days of AIA. After four days AIA, GLS-ir was elevated significantly in all sizes of DRG neurons. After eight days AIA, GLS-ir remained elevated in small (<400 µm²), presumably nociceptive neurons. Western blot analysis of the L4 DRG at day four AIA confirmed the elevated GLS-ir. The present study indicates that GLS expression is increased in the chronic stage of inflammation and may be a target for chronic pain therapy.
authors.affiliation: Anatomy and Cell Biology, Oklahoma State University Center for Health Sciences, 1111 West 17th Street, Tulsa, OK 74107, USA. e.matthew.hoffman@gmail.com.
authors.forename: E Matthew
authors.initials: EM
authors.lastname: Hoffman
authors.affiliation: Anatomy and Cell Biology, Oklahoma State University Center for Health Sciences, 1111 West 17th Street, Tulsa, OK 74107, USA. zijia.zhang@okstate.edu.
authors.forename: Zijia
authors.initials: Z
authors.lastname: Zhang
authors.affiliation: Anatomy and Cell Biology, Oklahoma State University Center for Health Sciences, 1111 West 17th Street, Tulsa, OK 74107, USA. ruben.schechter@okstate.edu.
authors.forename: Ruben
authors.initials: R
authors.lastname: Schechter
authors.affiliation: Anatomy and Cell Biology, Oklahoma State University Center for Health Sciences, 1111 West 17th Street, Tulsa, OK 74107, USA. kenneth.miller@okstate.edu.
authors.forename: Kenneth E
authors.initials: KE
authors.lastname: Miller
mesh_terms: D000818:Animals; D001169:Arthritis, Experimental / Q000201:enzymology*; D005260:Female; D005620:Freund's Adjuvant / Q000009:adverse effects; D005727:Ganglia, Spinal / Q000187:drug effects / Q000201:enzymology*; D005972:Glutaminase / Q000378:metabolism*; D006614:Hindlimb / Q000293:injuries*; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D015854:Up-Regulation
chemical_list: D005620:Freund's Adjuvant; D005972:Glutaminase
keywords: adjuvant-induced arthritis; complete Freund’s adjuvant; dorsal root ganglion; glutamate; glutaminase