title: Capsaicin-like effect of resiniferatoxin in the rat stomach.
abstract: Neurochemical and functional studies were performed to investigate and to compare the effects of resiniferatoxin and capsaicin in the rat stomach. Neonatal administration of resiniferatoxin (0.6-1.6 mumol/kg subcutaneously (s.c.)) produced a marked decrease in gastric calcitonin gene-related peptide-like immunoreactivity in both secretory and non-secretory region of the stomach. Almost complete depletion of the peptide was determined by neonatal administration of capsaicin (164 mumol/kg s.c.). Vasoactive intestinal polypeptide-like immunoreactivity was concomitantly unaffected by resiniferatoxin or capsaicin, thus showing the selectivity of action of the neurotoxins on gastric afferent fibers. Oral administration of an equimolar dose (0.3 nmol/kg) of resiniferatoxin or capsaicin together with 50% ethanol reduced at a similar extent gastric haemorrhagic lesions produced by the mucosal barrier-breaker agent. These findings provide evidence that resiniferatoxin and capsaicin may act on a common neuronal target in the rat stomach and that the acute exciting (protective) effect is of the same magnitude.
authors.affiliation: Pharmacology Department, Malesci Pharmaceuticals, Firenze, Italy.
authors.forename: M
authors.initials: M
authors.lastname: Tramontana
authors.forename: D
authors.initials: D
authors.lastname: Renzi
authors.forename: C
authors.initials: C
authors.lastname: Panerai
authors.forename: C
authors.initials: C
authors.lastname: Surrenti
authors.forename: F
authors.initials: F
authors.lastname: Nappi
authors.forename: L
authors.initials: L
authors.lastname: Abelli
authors.forename: S
authors.initials: S
authors.lastname: Evangelista
mesh_terms: D000284:Administration, Oral; D000818:Animals; D000831:Animals, Newborn; D015740:Calcitonin Gene-Related Peptide / Q000096:biosynthesis*; D002211:Capsaicin / Q000008:administration & dosage / Q000494:pharmacology* / Q000633:toxicity; D004224:Diterpenes / Q000008:administration & dosage / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D000431:Ethanol / Q000633:toxicity; D005753:Gastric Mucosa / Q000187:drug effects* / Q000294:innervation / Q000378:metabolism; D006471:Gastrointestinal Hemorrhage / Q000139:chemically induced / Q000503:physiopathology / Q000517:prevention & control; D007279:Injections, Subcutaneous; D008297:Male; D009475:Neurons, Afferent / Q000737:chemistry / Q000187:drug effects / Q000378:metabolism; D009498:Neurotoxins / Q000494:pharmacology / Q000633:toxicity; D051381:Rats; D013276:Stomach Ulcer / Q000139:chemically induced / Q000503:physiopathology / Q000517:prevention & control; D014660:Vasoactive Intestinal Peptide / Q000096:biosynthesis
chemical_list: D004224:Diterpenes; D009498:Neurotoxins; D014660:Vasoactive Intestinal Peptide; D000431:Ethanol; C024353:resiniferatoxin; D015740:Calcitonin Gene-Related Peptide; D002211:Capsaicin