Differential regulation of smooth muscle contraction in rabbit internal anal sphincter by substance and bombesin

Khalil N. Bitar, Craig Hillemeier, Piero Biancani

Research output: Contribution to journalArticle

22 Scopus citations

Abstract

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 (10-9M) and was not affected by the PKC antagonist H7 (10-6M). 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.

Original languageEnglish (US)
Pages (from-to)2429-2434
Number of pages6
JournalLife Sciences
Volume47
Issue number26
DOIs
StatePublished - 1990

All Science Journal Classification (ASJC) codes

  • Biochemistry, Genetics and Molecular Biology(all)
  • Pharmacology, Toxicology and Pharmaceutics(all)

Fingerprint Dive into the research topics of 'Differential regulation of smooth muscle contraction in rabbit internal anal sphincter by substance and bombesin'. Together they form a unique fingerprint.

  • Cite this