Secretory rates for immunoreactive atrial natriuretic peptide (ANP) by 7-8 day-old primary cultures of atrial myocytes from adult rats (with myocyte contraction inhibited by tetrodotoxin (TTX)) were (a) constant for at least two hours, and (b) significantly slowed by forskolin (1, 5, and 25 μM), dibutyryl cyclic adenosine monophosphate (1 mM), or isobutylmethylxanthine (100 μM). The substantial rates of ANP secretion which persisted in cells rendered noncontracting either by inhibiting Ca2+ influx via reduction of external [Ca2+] to <10-7 M or by inhibiting sarcoplasmic reticulum Ca2+ release with 100 μM ryanodine were significantly slowed by 25 μM forskolin, but forskolin sensitivity was lost by cells exposed simultaneously to external Ca2+ concentration of <10-7 M and 100 μM ryanodine. Quiescent myocytes whose ANP secretory rate was depressed by forskolin remained responsive to secretory stimulation by phorbol ester.
|Number of pages||7|
|Journal||Biochemical and Biophysical Research Communications|
|Publication status||Published - Nov 30 1988|
All Science Journal Classification (ASJC) codes
- Molecular Biology
- Cell Biology