title: The mucosal potential elicited by noxious chemical stimuli with CO2 in rats: is it a peripheral nociceptive event?
abstract: Negative mucosal potentials (NMPs) were recorded from the nasal respiratory mucosa in rats following retrograde stimulation with CO2 through a tube advanced to the nasopharynx. Local application of capsaicin (3 mg in 0.3 ml solvent, n = 5) and lidocaine (31 mg in 0.3 ml solvent, n = 5) eliminated the NMPs and cortical responses in the EEG. A quantitative reduction in NMPs was found following systemic pretreatment with capsaicin (cumulative dose, 200 mg/kg, n = 4), but not with guanethidine (50 mg/kg s.c., n = 4). Blood flow measurements and NMPs were obtained from the same recording position (n = 4). Onset of blood flow changes (1200-4800 ms) appeared significantly later than the onset of NMPs (120-500 ms). On the basis of these results a sensory neurogenic origin of the NMP is assumed.
authors.affiliation: Department of Pharmacology and Toxicology, University of Erlangen-Nuernberg, F.R.G.
authors.forename: N
authors.initials: N
authors.lastname: Thürauf
authors.forename: I
authors.initials: I
authors.lastname: Friedel
authors.forename: C
authors.initials: C
authors.lastname: Hummel
authors.forename: G
authors.initials: G
authors.lastname: Kobal
mesh_terms: D000818:Animals; D002211:Capsaicin / Q000494:pharmacology; D002245:Carbon Dioxide / Q000494:pharmacology*; D004569:Electroencephalography; D005071:Evoked Potentials / Q000187:drug effects; D006145:Guanethidine / Q000494:pharmacology; D008012:Lidocaine / Q000494:pharmacology; D008297:Male; D009297:Nasal Mucosa / Q000502:physiology*; D009474:Neurons / Q000187:drug effects; D009619:Nociceptors / Q000187:drug effects*; D010525:Peripheral Nerves / Q000187:drug effects*; D051381:Rats; D011919:Rats, Inbred Strains; D013268:Stimulation, Chemical; D013564:Sympathetic Nervous System / Q000166:cytology / Q000187:drug effects; D014276:Trigeminal Nerve / Q000502:physiology
chemical_list: D002245:Carbon Dioxide; D008012:Lidocaine; D002211:Capsaicin; D006145:Guanethidine