Reduction of [Ca(2+)](i) restores uncoupled beta-adrenergic signaling in isolated perfused transgenic mouse hearts.
Serikov. V B VB; Petrashevskaya. N N NN; Canning. A M AM; Schwartz. A A
Key Findings
- High extracellular calcium (2 mmol/L) blunts beta‑adrenergic signaling in mouse hearts
- Reducing calcium to 0.75‑1.5 mmol/L restores near‑normal beta‑adrenergic responsiveness
- The effect was consistent across three different transgenic heart models
Practical Outcomes
- For biohackers, the work hints that too much calcium in the bloodstream might dampen the heart’s ability to respond to stress hormones, so keeping calcium levels in a moderate range could be beneficial. However, the data come from isolated mouse hearts with genetic modifications, so direct recommendations for human calcium intake or supplementation are premature and need clinical validation.
Summary
The study found that when the calcium level in the fluid surrounding isolated mouse hearts was too high, the hearts didn’t respond well to beta‑adrenergic signals (the same signals that increase heart rate and strength). Dropping the calcium to a lower, more normal range restored the heart’s normal response. This was true in three different genetically altered mouse models.
Abstract
The effects of alterations in calcium in the perfusion media were studied on ss-adrenergic coupling in isolated hearts from 3 different transgenic mice: cardiac-specific overexpressed alpha(1) subunit of L-type calcium channel, overexpressed Galpha(q), and phospholamban knockout. Isolated hearts from all 3 models, when studied at [Ca(2+)] of 2 mmol/L in the perfusate, showed the usual blunted or no response to ss-adrenergic stimulation. Lowering [Ca(2+)] to 0.75 to 1.5 mmol/L unloaded the hearts of calcium and restored to nearly normal the responsiveness to ss-agonist stimulation.
Study Information
pubmed
2001
2001-01-19T00:00:00.000Z
10.1161/01.res.88.1.9