title: Age-dependent effect of secretagogues during colonic maturation.
abstract: Intestinal secretory response is altered during colonic development. The aim of this report was to study the developmental changes of the Ca(2+)- and cAMP-induced regulatory pathways with special attention to the direct and indirect effect of secretagogues on the colonic epithelium. We investigated the effect of bethanechol, 5-hydroxytryptamine (5-HT), and histamine on Cl(-) secretion and stimulation of intracellular Ca(2+) ([Ca(2+)](i)) and cAMP in the distal colon of suckling, weanling and adult rats. In the presence of tetrodotoxin, immature colon of suckling and weanling rats displayed higher potency (EC(50)) of 5-HT to stimulate Cl(-) secretion, whereas the potency of histamine was not changed during development. The potency of bethanechol was reduced during weaning and partially restored in adulthood. 5-HT increased cAMP level similarly in both neonatal and adult colonic crypts, but the adults had higher basal level of cAMP than suckling rats. Also the effect of bethanechol on [Ca(2+)](i) was independent of colonic maturation. The results suggest that colonic Cl(-) secretion displays developmental changes of regulation depending on the non-neural secretagogue-signalling pathway and that these developmental changes seem to be localized somewhere outside colonocytes.
authors.affiliation: Institute of Physiology, Czech Academy of Sciences, Vídenská 1083, CZ-142 20 Prague 4, Czech Republic.
authors.forename: Libor
authors.initials: L
authors.lastname: Mrnka
authors.forename: Sergej
authors.initials: S
authors.lastname: Beskid
authors.forename: Oksana
authors.initials: O
authors.lastname: Sevastyanova
authors.forename: Jana
authors.initials: J
authors.lastname: Bryndová
authors.forename: Jirí
authors.initials: J
authors.lastname: Pácha
mesh_terms: D000367:Age Factors; D000818:Animals; D000833:Animals, Suckling; D018723:Bethanechol / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism; D003106:Colon / Q000187:drug effects / Q000378:metabolism / Q000502:physiology*; D000242:Cyclic AMP / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004594:Electrophysiology; D004848:Epithelium / Q000187:drug effects / Q000502:physiology; D005260:Female; D006632:Histamine / Q000494:pharmacology; D006873:Hydroquinones / Q000494:pharmacology; D066298:In Vitro Techniques; D007413:Intestinal Mucosa / Q000187:drug effects / Q000378:metabolism; D008297:Male; D051381:Rats; D017208:Rats, Wistar; D012701:Serotonin / Q000494:pharmacology; D013779:Tetrodotoxin / Q000494:pharmacology; D013806:Theophylline / Q000494:pharmacology; D014886:Weaning
chemical_list: D006873:Hydroquinones; D018723:Bethanechol; C019359:2,5-di-tert-butylhydroquinone; D012701:Serotonin; D013779:Tetrodotoxin; D006632:Histamine; D013806:Theophylline; D000242:Cyclic AMP; D002118:Calcium