title: Interactions of bradykinin and norepinephrine on rat cutaneous nociceptors in both normal and inflamed conditions in vitro.
abstract: Many inflammatory chemical mediators excite or sensitize nociceptors, which had led some researchers to believe that they may interact with each other to maintain a persistent painful state. We examined how the excitatory mediators norepinephrine (NE) and bradykinin (BK) interact, using single fiber recordings from cutaneous nociceptors. We observed that NE augmented the BK-induced response in both control and adjuvant-inflamed rats in a way different from NE-induced excitation in inflamed animals only. BK also tended to augment the NE-induced response (examined only in inflamed rats). Our results provide the first evidence that BK and NE synergistically interact on nociceptors.
authors.affiliation: Department of Neural Regulation, Research Institute of Environmental Medicine, Nagoya University, Furo, Chikusa, Nagoya 464-8601, Japan.
authors.forename: Ratan Kumar
authors.initials: RK
authors.lastname: Banik
authors.forename: Jun
authors.initials: J
authors.lastname: Sato
authors.forename: Rocio
authors.initials: R
authors.lastname: Giron
authors.forename: Hiroki
authors.initials: H
authors.lastname: Yajima
authors.forename: Kazue
authors.initials: K
authors.lastname: Mizumura
mesh_terms: D000818:Animals; D001920:Bradykinin / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D004347:Drug Interactions; D005620:Freund's Adjuvant; D066298:In Vitro Techniques; D007249:Inflammation / Q000139:chemically induced / Q000378:metabolism; D008297:Male; D009412:Nerve Fibers / Q000187:drug effects* / Q000502:physiology; D009431:Neural Conduction / Q000187:drug effects; D009619:Nociceptors / Q000187:drug effects / Q000378:metabolism*; D009638:Norepinephrine / Q000494:pharmacology*; D051381:Rats; D011917:Rats, Inbred Lew; D012867:Skin / Q000187:drug effects / Q000294:innervation*; D013268:Stimulation, Chemical
chemical_list: D005620:Freund's Adjuvant; D001920:Bradykinin; D009638:Norepinephrine