title: Use of the Operant Orofacial Pain Assessment Device (OPAD) to measure changes in nociceptive behavior.
abstract: We present an operant system for the detection of pain in awake, conscious rodents. The Orofacial Pain Assessment Device (OPAD) assesses pain behaviors in a more clinically relevant way by not relying on reflex-based measures of nociception. Food fasted, hairless (or shaved) rodents are placed into a Plexiglas chamber which has two Peltier-based thermodes that can be programmed to any temperature between 7 °C and 60 °C. The rodent is trained to make contact with these in order to access a reward bottle. During a session, a number of behavioral pain outcomes are automatically recorded and saved. These measures include the number of reward bottle activations (licks) and facial contact stimuli (face contacts), but custom measures like the lick/face ratio (total number of licks per session/total number of contacts) can also be created. The stimulus temperature can be set to a single temperature or multiple temperatures within a session. The OPAD is a high-throughput, easy to use operant assay which will lead to better translation of pain research in the future as it includes cortical input instead of relying on spinal reflex-based nociceptive assays.
authors.affiliation: Department of Oral and Maxillofacial Surgery, University of Florida College of Dentistry. ethan241@gmail.com
authors.forename: Ethan M
authors.initials: EM
authors.lastname: Anderson
authors.forename: Richard
authors.initials: R
authors.lastname: Mills
authors.forename: Todd A
authors.initials: TA
authors.lastname: Nolan
authors.forename: Alan C
authors.initials: AC
authors.lastname: Jenkins
authors.forename: Golam
authors.initials: G
authors.lastname: Mustafa
authors.forename: Chris
authors.initials: C
authors.lastname: Lloyd
authors.forename: Robert M
authors.initials: RM
authors.lastname: Caudle
authors.forename: John K
authors.initials: JK
authors.lastname: Neubert
mesh_terms: D000818:Animals; D003216:Conditioning, Operant; D005157:Facial Pain / Q000503:physiopathology*; D008297:Male; D051379:Mice; D059226:Nociceptive Pain / Q000503:physiopathology*; D010147:Pain Measurement / Q000295:instrumentation* / Q000379:methods*; D051381:Rats; D017207:Rats, Sprague-Dawley