[Differences in activity between substance P and substance P-heptapeptide as studied on the phenomenon of "gut dependence" in rats (author's transl)].
Naloxone causes a tonic contraction (= "gut dependence") of the ileum in morphine-dependent rats. This "gut dependence" can be antagonized by morphine (2.5 X 10(-7) g/ml). Substance P-undecapeptide (SP1-11) produces a tonic contraction of the ileum in morphine-independent rats and also in morphine-dependent rats. In the latter, this tonic contraction is comparable with the naloxone-induced contraction. When morphine-dependent rats with naloxone-induced "gut dependence" are given SP1-11, they show an additional increase in tonus followed by a rapid tonus inhibition. Substance P-heptapeptide (SP5-11) also causes a naloxone-like contraction in both the morphine-dependent and the morphine-independent rats. In contrast to SP1-11, SP5-11 produces neither a tonus superposition nor a tonus inhibition in morphine-dependent rats with naloxone-induced "gut dependence". The fact that SP5-11 does not, in contrast to SP1-11, exert these two effects (tonus superposition and subsequent tonus inhibition) is indicative of differences between the mechanisms of the two Substance P sequences.
D000818:Animals; D006801:Humans; D007082:Ileum / Q000187:drug effects; D066298:In Vitro Techniques; D008297:Male; D009021:Morphine Dependence / Q000503:physiopathology*; D009119:Muscle Contraction / Q000187:drug effects; D009130:Muscle, Smooth / Q000187:drug effects*; D009270:Naloxone / Q000494:pharmacology; D010446:Peptide Fragments / Q000494:pharmacology*; D051381:Rats; D013373:Substance P / Q000494:pharmacology*
D010446:Peptide Fragments; D013373:Substance P; D009270:Naloxone; C031661:substance P (5-11)
Wirkungsunterschiede zwischen Substanz P und Substanz P-Heptapeptid, untersucht am Phänomen der "gut dependence" bei Ratten.