Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P20366 (substance P)
 21,176 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Substance P and bombesin induce contraction of isolated IAS smooth muscle cells by different intracellular mechanisms. The cells contracted in a dose dependent manner to both peptides. The kinetics of contraction were different. Substance P induced contraction peaked at 30 seconds and declined in a time dependent manner while bombesin induced contraction peaked at 30 seconds and was maintained for up to 8 minutes. The absence of extracellular calcium in the medium (0 calcium and 2 mM EGTA) had no affect on substance P induced contraction while it blocked bombesin induced contraction. Substance P induced contraction was blocked by the calmodulin antagonist W7 (10(-9)M) and was not affected by the PKC antagonist H7 (10(-6)M). Bombesin induced contraction was blocked by the PKC antagonist H7 and was not affected by the calmodulin antagonist W7. Our data indicate that substance P induces a transient contraction utilizing intracellular calcium and a calmodulin dependent pathway, while bombesin induces a sustained contraction utilizing calcium from extracellular sources and a calmodulin independent pathway.
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PMID:Differential regulation of smooth muscle contraction in rabbit internal anal sphincter by substance P and bombesin. 170 75

In summary, PACAP exerts a biphasic effect (an initial contraction followed by a relaxation) in the IAS. The initial contractile effect with higher concentrations of PACAP was found to be mediated by the activation of PACAP receptor at the substance P-containing nerve terminals. The PACAP receptor(s) responsible for the inhibitory action of the neuropeptide is(are) hypothesized to be present in the IAS smooth muscle cells and on the myenteric nerve terminals. The exact nature and the role of PACAP and the PACAP receptors in the inhibitory neurotransmission, the relationship of PACAP receptors with substance P-containing neurons and IAS smooth muscle cells, and interactions with the NOS pathway and VIP remain to be determined.
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PMID:Sites of actions of contractile and relaxant effects of pituitary adenylate cyclase activating peptide (PACAP) in the internal anal sphincter smooth muscle. 992 59