Release of acetylcholine by chick embryo heart before innervation.
1. In chick embryo hearts, 3-day-old and not yet innervated, repetitive direct stimulation causes a transitory inhibition of the spontaneous rhythm.2. The degree of post-stimulation inhibition depends on the frequency and duration of the artificial stimulation and on the concentration of K and Ca ions in the extracellular solution.3. After treatment with atropine (10(-5) g/ml.) post-stimulation inhibition is no longer observed. The spontaneous rhythm is accelerated by atropine. The findings therefore suggest that an ACh-like substance is released from the non-innervated embryonic heart during activity.4. By use of the dorsal muscle of the leech for biological assay the liberation of an ACh-like substance from the non-innervated embryonic heart was confirmed.
D000109:Acetylcholine / Q000032:analysis / Q000378:metabolism*; D000818:Animals; D001285:Atropine / Q000494:pharmacology; D001681:Biological Assay; D002118:Calcium / Q000502:physiology; D002642:Chick Embryo
D001285:Atropine; D000109:Acetylcholine; D002118:Calcium