Authors: Maighdlin Patterson, Po-Jen Chiang, Hannah Carey, Karen Ball, Charles Chung
Published: 2024-10-09
DOI: 10.1161/res.135.suppl_1.mo117
Source: Full article
Introduction: During hibernation, 13-lined ground squirrels cycle between torpor and intermittent bouts of arousal (IBA). Bouts of IBA last 12-48 hours, during which heart rates rise from 2-4 bpm in torpor to 300 bpm during IBA before returning to torpor. Thus, rates of contractility and relaxation and their mechanisms must rapidly change. Phosphorylation of cardiac troponin I (cTnI) at serine 23/24 (pSer23/24) has been shown to decrease calcium sensitivity and increase the rate of myocardial relaxation, enabling faster heart rates. Heat shock protein 27 (HSP27) has been shown to protect contractility by stabilizing troponin.