Temperature alters the inotropic and chronotropic effect of D-dopamine receptor stimulation in the mammalian atrium.

Naunyn Schmiedebergs Arch Pharmacol

Institute for Pharmacology and Toxicology, Medical Faculty, Martin-Luther-University Halle-Wittenberg, Magdeburger Straße 4, 06097, Halle (Saale), Germany.

Published: May 2025


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Article Abstract

We studied how hypothermia and hyperthermia may change the efficacy and/or potency of dopamine to augment the force of contraction in atria of mice with cardiac overexpression of the human D-dopamine receptor (D-TG). We measured the force of contraction on paced (1 Hz) left atria and spontaneously beating right atria of these D-TG mice in vitro. The intrinsic heart beat in the right atria from D-TG mice lowered when we reduced the temperature (24 °C, hypothermia) and elevated when we raised the temperature (42 °C, hyperthermia) in the organ baths. In addition, the efficacy of dopamine (0.001-100 µM) to augment the force of contraction was diminished in the left and right D-TG mouse atrial preparations under 24 °C and 42 °C compared to 37 °C in the organ baths. Likewise, the rise in force after dopamine was diminished at 24 °C and 42 °C compared to 37 °C in paced human atrial preparations (HAP) obtained from patients who underwent surgery. In conclusion, the inotropic effects of dopamine in D-TG mice and in human atrial preparation via D-dopamine receptors, but also the effects of dopamine in D-TG mice on the heartbeat, change with ambient temperature.

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http://dx.doi.org/10.1007/s00210-025-04313-6DOI Listing

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