The second messenger system(s) mediating the secretion of atrial natriuretic peptide (ANP) from the isolated rat heart during rapid cardiac pacing.

This study demonstrates that rapid cardiac pacing elevates Atrial Natriuretic Peptide (ANP) levels, independently from atrial stretch. The second messenger system mediating this response was examined. The phosphoinositide system, generally regarded to be important in mediating ANP release, was shown to play only a modulating role during rapid cardiac pacing. The main mediator would appear to be calcium, and a non-calmodulin dependent, calcium mediated system controlling ANP release during rapid cardiac pacing is suggested.