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Stimulation and inhibition of gastrointestinal propulsion induced by substance P and substance K in the rat
Author(s) -
Holzer P.
Publication year - 1985
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.1476-5381.1985.tb09462.x
Subject(s) - substance p , atropine , gastric emptying , neurokinin a , medicine , chemistry , endocrinology , gastrointestinal tract , intraperitoneal injection , stimulant , pharmacology , neuropeptide , stomach , receptor
1 Substance P and substance K (neurokinin A) (dose range: 0.08–80 nmol kg −1 ) were tested for their effects on gastrointestinal propulsion in the rat. The peptides were given by intraperitoneal injection concurrently with the intragastric administration of a test meal containing charcoal and 51 Cr. 2 Examination 3 min after the test meal showed that high doses of substance P (> 0.74 nmol kg −1 ) and substance K (> 8.8 nmol kg −1 ) inhibited gastric emptying and gastrointestinal transit. This inhibitory effect was changed to a stimulant effect by pretreatment of the rats with atropine (3.5 μmol kg −1 ). Guanethidine pretreatment (67 μmol kg −1 ) revealed a facilitatory effect of low doses of the two tachykinins (about 1 nmol kg −1 ) on gastrointestinal propulsion. 3 Examination 15 min after the test meal demonstrated that substance P (> 0.74 nmol kg −1 ) dose‐dependently enhanced gastrointestinal propulsion, an effect that was also seen after atropine pretreatment. Low doses of substance K (about 1 nmol kg −1 ) also stimulated gastrointestinal propulsion but this effect was abolished by atropine. In addition, atropine pretreatment revealed a stimulant effect of high doses of substance K (88 nmol kg −1 ) on gastric emptying. 4 These results show that the effects of substance P and substance K on gastrointestinal propulsion vary with dose and time and involve, at least partly, activation of the autonomic nervous system.