Currently, the mechanism of the chronotropic ability of stem cells modified to express the hyperpolarization-activated cyclic nucleotide-gated (HCN) gene remains to be elucidated. The present study assessed the effects of mouse (m)HCN2 gene modification on the expression of chronotropic relevant receptors, adrenergic receptor β1 (Adrb1) and cholinergic receptor muscarinic M2 (Chrm2), in bone ma...

Pericardial distensibility curves and chronotropic changes accompanying pericardial distension were investigated in 24 isolated perfused frog hearts. The distensibility curve had a slow phase and a steep phase attributable to elastic and collagen components of the pericardium. Changes in pericardial pressure were accompained with reversible changes in the heart rate. The mean control rate rose ...

Angiotensin II (Ang II) elicits Ang II type 1 receptor (AT1-R)-mediated increases in neuronal firing within the hypothalamus and brainstem that are ultimately responsible for physiological actions such as increased blood pressure and fluid intake. Although there is a growing literature on the intracellular mechanisms that mediate the actions of Ang II via AT1-R in neurons, little is known about...

OBJECTIVES The purpose of this study was to compare the prognostic impact of clinical and biomarker correlates of resting heart rate (HR) and chronotropic incompetence in heart failure (HF) patients. BACKGROUND The mechanisms and underlying pathophysiological influences of HR abnormalities in HF are incompletely understood. METHODS In a prospective pilot study, 81 patients with advanced sys...

The effects of intravenous administration of sodium nitroprusside to a donor dog on cardiac pacemaker activity and contractility were investigated in a cross-circulated dog heart preparation; i.e., the isolated atrial muscle was perfused with blood from a pentobarbital anesthetized donor dog. Intravenous administration of nitroprusside (1-10 micrograms/Kg) caused a hypotension with tachycardia,...