Stimulation of histamine H-receptors produces a positive inotropic effect in the human atrium.

There is a controversy whether histamine H-receptor activation raises or lowers or does not affect contractility in the human heart. Therefore, we studied stimulation of H-receptors in isolated electrically stimulated (one beat per second) human atrial preparations (HAP). For comparison, we measured force of contraction in left atrial preparations (LA) from mice with overexpression of the histamine H-receptor in the heart (H-TG).

Contractile effects of stimulation of D-dopamine receptors in the isolated human atrium.

Dopamine receptors have been claimed not to directly increase contractility in the human heart. Therefore, we performed contraction experiments in isolated electrically driven human atrial preparations (HAP). For comparison, we performed contraction experiments with left atrial preparations of transgenic mice which harbor a cardiac overexpression of human D-dopamine receptors (D-TG).

Effects of hallucinogenic drugs on the human heart.

Hallucinogenic drugs are used because they have effects on the central nervous system. Their hallucinogenic effects probably occur via stimulation of serotonin receptors, namely, 5-HT-serotonin receptors in the brain. However, a close study reveals that they also act on the heart, possibly increasing the force of contraction and beating rate and may lead to arrhythmias.

Effects of congeners of amphetamine on the human heart.

Central stimulatory and hallucinogenic drugs of abuse like amphetamine and most congeners of amphetamine can have cardiac harmful effects. These cardiac side effects can lead to morbidities and death. In this paper, we review current knowledge on the direct and indirect effects of these amphetamine congeners on the mammalian heart-more specifically, the isolated human heart muscle preparation.

Initial characterization of a transgenic mouse with overexpression of the human D-dopamine receptor in the heart.

Dopamine can exert effects in the mammalian heart via five different dopamine receptors. There is controversy whether dopamine receptors increase contractility in the human heart. Therefore, we have generated mice that overexpress the human D-dopamine receptor in the heart (D-TG) and hypothesized that dopamine increases force of contraction and beating rate compared to wild-type mice (WT).