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Updated: Oct 2, 2026

Optical Mapping of Intra-Sarcoplasmic Reticulum Ca2+ and Transmembrane Potential in the Langendorff-perfused Rabbit Heart
Published on: September 10, 2015
External detection of beta-adrenoreceptors with 125I-hydroxybenzylpindolol in isolated perfused hearts
Abstract:
To assess the feasibility of characterizing beta-adrenoreceptors externally with ligands labeled with gamma-emitting radionuclides, we infused 125I-hydroxybenzylpindolol (125I-HYP) a potent, high affinity, beta-adrenoreceptor ligand into isolated perfused hearts and monitored uptake and release of the label externally with a gamma probe. Perfusion with specific beta-adrenergic displacing significantly increased the turnover rate constant of 125I-HYP in comparison to that obtained with non-specific displacing agents. After modifying beta-adrenoreceptor density by pretreatment of animals with thyroid hormone, an increase in 125I-HYP uptake was observed. Thus, beta-adrenoreceptor occupancy and increases in beta-adrenoreceptor density can be detected externally with an approach which may offer promise for their characterization in vivo with radiolabeled adrenergic ligands.
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