Any process that modulates the extent of heart contraction, changing the force with which blood is propelled [goid 2026] [evidence IEA]; The process that stops, prevents or reduces the frequency, rate or extent of G-protein coupled receptor protein signaling pathway activity after prolonged stimulation with an agonist of the pathway [goid 2029] [evidence IEA]; Any process which decreases the force of heart muscle contraction mediated by chemical signaling, hormonal, autocrine or paracrine [goid 3108] [pmid 15051637] [evidence IMP]; The cascade of processes by which a signal interacts with a receptor, causing a change in the level or activity of a second messenger or other downstream target, and ultimately effecting a change in the functioning of the cell [goid 7165] [evidence IEA]; The series of molecular signals generated as a consequence of a muscarinic acetylcholine receptor binding to one of its physiological ligands; muscarinic acetylcholine receptors activate inhibitory G proteins and can be activated by the fungal alkaloid muscarine [goid 7213] [evidence ISS]; The series of molecular signals generated as a consequence of a tachykinin, i.e. a short peptide with the terminal sequence (Phe-X-Gly-Leu-Met-NH2), binding to a cell surface receptor [goid 7217] [pmid 17986524] [evidence IDA]; The process whose specific outcome is the progression of the heart over time, from its formation to the mature structure. The heart is a hollow, muscular organ, which, by contracting rhythmically, keeps up the circulation of the blood [goid 7507] [evidence IEA]; The posttranslational phosphorylation of peptidyl-serine to form peptidyl-O-phospho-L-serine [goid 18105] [evidence ISS]; Any process that activates or increases the frequency, rate or extent of the regulated release of a catecholamine [goid 33605] [evidence ISS]; Any process that stops, prevents or reduces the frequency, rate or extent of striated muscle contraction [goid 45988] [pmid 15051637] [evidence IMP]; Muscle contraction of cardiac muscle tissue [goid 60048] [pmid 15051637] [evidence IMP]