Open AccessNeurogenic “Off” Contractions Are Mediated by NK2-Receptors in the Circular Muscle of Guinea Pig Ileum
Author(s) -
Norihiro Suzuki,
Ken Muramatsu,
Yasuo Gomi
Publication year - 1994
Publication title -
japanese journal of pharmacology/japanese journal of pharmacology
Language(s) - English
Resource type - Journals
eISSN - 1347-3506
pISSN - 0021-5198
DOI - 10.1254/jjp.64.213
Subject(s) - tetrodotoxin , atropine , ileum , guinea pig , antagonist , receptor , contraction (grammar) , endocrinology , muscle contraction , medicine , chemistry , anatomy , biology
In guinea pig ileal circular muscle, electrical stimulations by a train of 10-100 pulses (0.05-msec duration, 10 Hz) produced tetrodotoxin-sensitive "off" contractions that were initiated upon the termination of stimulations. Atropine at 10(-6) M did not inhibit the "off" contractions. FK224 at 10(-5) M, a dual antagonist for NK1- and NK2-receptors, but not 10(-7) M CP-96,345, an antagonist for NK1-receptors, almost abolished the "off" contractions in the presence of atropine. These results suggest that the neurogenic "off" contraction was mediated mainly by NK2-receptors in the circular muscle of guinea pig ileum.