Cyclic amp-independent relaxation of depolarized rat ileal smooth muscle by isoproterenol

Joel D. Schiff, Norbert I.A. Overweg

Research output: Contribution to journalArticlepeer-review


Isoproterenol brings about a rapid transient relaxation of depolarized ileal smooth muscle as well as a longer lasting decline in tension. Only the latter effect is mimicked by dibutyryl cyclic AMP or by phosphodiesterase inhibitors. Beta adrenergic blocking agents cause a rapid transient contraction in preparations relaxed by isoproterenol but not in preparations relaxed by the other agents, and this effect persists when influx of Ca2+ from the extracellular space is prevented. The transient component of the isoproterenol-induced relaxation is therefore attributed to sequestration of Ca2+ at intracellular sites, and the contraction which follows the subsequent addition of beta blocking agents is due to release of Ca2+ from these sites.

Original languageEnglish (US)
Pages (from-to)2299-2305
Number of pages7
JournalLife Sciences
Issue number23
StatePublished - Dec 4 1978

ASJC Scopus subject areas

  • General Pharmacology, Toxicology and Pharmaceutics
  • General Biochemistry, Genetics and Molecular Biology


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