Calcium-dependent modulation by melatonin of the circadian rhythm in malarial parasites.

Antimalarial drugs disrupt ion homeostasis in malarial parasites

“…These findings are of major significance, because they raise the possibility that chloroquine and artemisinin action in malaria parasites may involve alterations in ion homeostasis. This is especially important in view of our work showing that IP 3 -dependent Ca 2+ signaling is involved in the progression of the malarial parasite cell cycle (Hotta et al 2000, Gazarini et al 2003, Beraldo et al 2005.…”

Flow cytometry as a tool for analyzing changes in Plasmodium falciparum cell cycle following treatment with indol compounds

“…Malaria parasites respond to external stimuli to adapt its life within host cells (28,29). Our group had previously reported that melatonin acts in the cell cycle of the human P. falciparum and the rodent malaria parasite Plasmodium chabaudi, synchronizing the parasites' developmental cycle during erythrocytic schizogony (5). The present data demonstrates that the presence of various concentrations of melatonin, serotonin, N-acetyl-serotonin (NAS) and tryptamine led to an increase in the percentage of multinucleated schizont forms of parasites, favoring synchronization of intraerythrocytic cycle of P. falciparum.…”

“…We have previously shown that this hormone is able to synchronize Plasmodium falciparum and P. chabaudi cell infections (5-7). The synchronicity was lost in vitro when parasites had been incubated with the melatonin antagonist luzindole; the same effect was obtained in vivo in pinealectomized mice and after the injection of luzindole (5). In P. falciparum, melatonin induces a complex signaling pathway with the participation of IP3 generation (8) and subsequent transients in cytosolic calcium concentration, cAMP production and protein kinase A (PKA) (9,10) and protease activation (11).…”

The influence of biological rhythms on host–parasite interactions

“…Yet hosts also 83 undoubtedly face the challenge of mitigating the deleterious effects of parasites when resources are 84 scarce, a situation that might favor investment into parasite tolerance versus resistance. For parasites, 85 not only does the host immune response impose risk, additional risks can be introduced by environmental 86 regimes during transmission [20] or environmental life stages [21]; which has led to parasite risk avoidance 87 strategies such as climate-driven arrested development [22]. For both hosts and parasites, therefore, 88 external environmental conditions impose selective pressure by providing fluctuating opportunity for 89 reproduction and risk of mortality.…”