Neurogenic and non-neurogenic mechanisms in response of rat distal colon muscle to dextran sulphate sodium treatment.
We studied, by organ bath methodology, how experimental colitis in rat, induced by the administration of dextran sulphate sodium (DSS) in the drinking water (3% for 3 or 7 days, or 5% for 7 days; Controls received ordinary tap water), may influence spontaneous, contractile activity of the longitudinal muscle layer. DSS treatment caused a dose-dependent increase in phasic contractile activity of the colon muscle. This effect needed an optimal preload of the tissues to be evident, and was non-neurogenic (i.e. myogenic and/or paracrine) in nature. Moreover, the DSS treatment appeared to impair a neurogenic, nitric oxide (NO)-dependent, relaxant response to the stretch (i.e. preload) applied to the tissues. Inducible NO synthase was localized by immunohistochemistry to infiltrating mononuclear cells in the colon wall. We propose that NO, via the inducible pathway, exerts marked effects on the neuromuscular apparatus in the DSS model of experimental colitis.
Börjesson
Lars
L
Department of Surgery, Institute of Surgical Sciences, Sahlgrenska University Hospital, SE-413 45 Göteborg, Sweden.
Delbro
Dick S
DS
D000818:Animals; D003092:Colitis / Q000139:chemically induced* / Q000201:enzymology; D003106:Colon / Q000187:drug effects* / Q000201:enzymology / Q000473:pathology; D016264:Dextran Sulfate / Q000633:toxicity*; D066298:In Vitro Techniques; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects* / Q000502:physiology; D019001:Nitric Oxide Synthase / Q000032:analysis / Q000096:biosynthesis; D052247:Nitric Oxide Synthase Type II; D051381:Rats; D017207:Rats, Sprague-Dawley
D016264:Dextran Sulfate; D019001:Nitric Oxide Synthase; D052247:Nitric Oxide Synthase Type II; C496318:Nos2 protein, rat