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Action of 5‐hydroxytryptamine on intestinal ion transport in the rat.
Author(s) -
Hardcastle J,
Hardcastle P T,
Redfern J S
Publication year - 1981
Publication title -
the journal of physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.802
H-Index - 240
eISSN - 1469-7793
pISSN - 0022-3751
DOI - 10.1113/jphysiol.1981.sp013933
Subject(s) - methysergide , hexamethonium , atropine , phenoxybenzamine , cyproheptadine , acetylcholine , chemistry , endocrinology , medicine , propranolol , in vivo , stimulation , phentolamine , cholinergic , pharmacology , serotonin , biology , biochemistry , receptor , microbiology and biotechnology
1. 5‐HT increased the electrical activity of rat jejunum both in vivo and in vitro. The increased potential difference and short‐circuit current resulted from a stimulation of electrogenic chloride secretion. NaCl absorption may also have been inhibited. 2. 5‐HT did not alter cyclic AMP levels in isolated enterocytes. 3. The 5‐HT response in vivo was unaffected by atropine, cyproheptadine, propranolol and hexamethonium. Phenoxybenzamine reduced the maximum response without affecting the dose required to produce a 50% maximum response. Methysergide, at a dose of 40 mg/kg, had a similar effect while a lower dose of 2 mg/kg produced no change. Mianserin competitively antagonized the response to 5‐HT, a dose of 2 mg/kg producing a fourfold increase in the amount of 5‐HT required to produce a 50% maximum response. 4. Acetylcholine and 5‐HT seem to act independently in inducing intestinal secretion since atropine did not block the response to 5‐HT and Mianserin did not alter the response to acetylcholine. 5. Experiments in which the intestinal villi or crypts were subjected to preferential damage suggested that 5‐HT primarily produced its response at the crypt cell level.