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Nitrergic modulation of cholinergic responses in the opossum lower oesophageal sphincter
Author(s) -
Cellek Selim,
Moncada Salvador
Publication year - 1997
Publication title -
british journal of pharmacology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.432
H-Index - 211
eISSN - 1476-5381
pISSN - 0007-1188
DOI - 10.1038/sj.bjp.0701497
Subject(s) - opossum , cholinergic , esophageal sphincter , neuroscience , medicine , biology , endocrinology , anatomy , disease , reflux
1 Electrical field stimulation (EFS) of the superfused lower oesophageal sphincter from opossum ( Monodelphis domestica ) elicited biphasic responses. The first phase (relaxation) was strictly dependent on the duration of the EFS. The second phase (contraction) started following termination of the EFS (15 Hz). EFS at frequencies above 15 Hz led only to contraction, which started immediately upon initiation of the stimulation. 2 In the presence of N G ‐nitro‐ L ‐arginine ( L ‐NOARG; 0.1–300 μ M ), the relaxation phase was abolished and the contractile response started with the initiation of EFS (at all frequencies) and was greater in magnitude. The contractile response to EFS was completely blocked with scopolamine (10 μ M ). 3 Exogenous acetylcholine (1–100 μ M ) elicited concentration‐dependent contractions of the sphincter in the presence of botulinum toxin. These contractions were abolished when EFS was applied during administration of acetylcholine. This inhibitory effect of EFS was completely reversed when the tissue was treated with L ‐NOARG (100 μ M ). 4 These results suggest that the cholinergic response in the opossum lower oesophageal sphincter is under nitrergic control.British Journal of Pharmacology (1997) 122 , 1043–1046; doi: 10.1038/sj.bjp.0701497