Phosphorylation at Serines 157 and 161 Is Necessary for Preserving Cardiac Expression Level and Functions of Sarcomeric Z-Disc Protein Telethonin.

In cardiac myocytes, the sarcomeric Z-disc protein telethonin is constitutively bis-phosphorylated at C-terminal residues S157 and S161; however, the functional significance of this phosphorylation is not known. We sought to assess the significance of telethonin phosphorylation , using a novel knock-in (KI) mouse model generated to express non-phosphorylatable telethonin ( ). and wild-type (WT) littermates were characterized by echocardiography at baseline and after sustained β-adrenergic stimulation isoprenaline infusion.

Facilitation of ischaemia-induced ventricular fibrillation by catecholamines is mediated by β and β agonism in the rat heart in vitro.

Background And Purpose: Antiarrhythmic β-blockers are used in patients at risk of myocardial ischaemia, but the survival benefit and mechanisms are unclear. We hypothesized that β-blockers do not prevent ventricular fibrillation (VF) but instead inhibit the ability of catecholamines to facilitate ischaemia-induced VF, limiting the scope of their usefulness.

Experimental Approach: ECGs were analysed from ischaemic Langendorff-perfused rat hearts perfused with adrenoceptor antagonists and/or exogenous catecholamines (CATs: 313 nM noradrenaline + 75 nM adrenaline) in a blinded and randomized study.

Is rate-pressure product of any use in the isolated rat heart? Assessing cardiac 'effort' and oxygen consumption in the Langendorff-perfused heart.

What is the central question of this study? Rate-pressure product (RPP) is commonly used as an index of cardiac 'effort'. In canine and human hearts (which have a positive force-frequency relationship), RPP is linearly correlated with oxygen consumption and has therefore been widely adopted as a species-independent index of cardiac work. However, given that isolated rodent hearts demonstrate a negative force-frequency relationship, its use in this model requires validation.