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BK 1 and BK 2 bradykinin receptors in the rat duodenum smooth muscle
Author(s) -
Feres Teresa,
Paiva Antonio C.M.,
Paiva Therezinha B.
Publication year - 1992
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 - 10.1111/j.1476-5381.1992.tb13396.x
Subject(s) - bradykinin , apamin , endocrinology , medicine , agonist , contraction (grammar) , muscle contraction , duodenum , biology , chemistry , receptor , bradykinin receptor , potassium channel
1 The dual action of bradykinin (relaxation and contraction) on the rat duodenum was investigated by studying its effect on adenosine 3′:5′‐cyclic monophosphate (cyclic AMP) levels in cultured duodenal smooth muscle cells, and the effects of apamin on the isolated muscle responses to agonists and antagonists of BK 1 and BK 2 receptors. 2 No change was observed in the cyclic AMP content of cultured cells incubated with up to 100 n m bradykinin. 3 Apamin (100–500 n m ) inhibited the relaxant component and enhanced the contractile component of the responses to bradykinin and to the BK 2 ‐specific analogue [Thi 5,8 , d ‐Phe 7 ]‐bradykinin. 4 Apamin (100–500 n m ) did not affect the contractile response of stretched duodenum preparations to the BK 1 ‐specific agonist des‐Arg 9 ‐bradykinin. 5 The BK 2 antagonist, [ d ‐Arg 0 Hyp 3 Thi 5,8 , d ‐Phe 7 ]‐bradykinin, at a concentration which completely inhibited the relaxant response to bradykinin and to [Thi 5,8 , d ‐Phe 7 ]‐bradykinin, also prevented the contraction in response to either agonist in the presence of apamin. 6 Our results demonstrate two populations of bradykinin receptors in rat duodenum: a BK 2 subtype responsible for the biphasic response of the non‐stretched duodenum, and a BK 1 subtype responsible for the contractile effect on the stretched tissue.