Naringin is a flavonoid glycoside found in citrus fruits and grapes with wide range of therapeutic actions. We aimed to study the inotropic effect naringin on rat-isolated atria, dissecting intracellular mechanisms involved this response. Concentration-response curves (0.003-6 mM) were obtained before after pre-incubation selective antagonists. Our results showed that presented biphasic respons...

Membrane depolarization, neurotransmitters, and hormones evoke a release of Ca2+ from intracellular Ca(2+)-storing organelles like the endoplasmic reticulum and, in muscle, the sarcoplasmic reticulum (SR). In turn, the released Ca2+ serves to trigger a variety of cellular responses. The presence of Ca2+ pumps to replenish intracellular stores was described more than 20 years ago. The presence o...

Hyperalgesic priming, an estrogen dependent model of the transition to chronic pain, produced by agonists at receptors that activate protein kinase C epsilon (PKCε), occurs in male but not in female rats. However, activation of second messengers downstream of PKCε, such as the ryanodine receptor, induces priming in both sexes. Since estrogen regulates intracellular calcium, we investigated the ...

In this study, we characterized the signalling pathway activated by acetylcholine that encodes Ca2+ oscillations in rat duodenum myocytes. These oscillations were observed in intact myocytes after removal of external Ca2+, in permeabilized cells after abolition of the membrane potential and in the presence of heparin (an inhibitor of inositol 1,4,5-trisphosphate receptors) but were inhibited by...

Previous studies have demonstrated that skeletal muscle from individuals susceptible to malignant hyperthermia (MH) has a defect associated with the mechanism of calcium release from its intracellular storage sites in the sarcoplasmic reticulum (SR). In this report we demonstrate that the [3H]ryanodine receptor of isolated MH-susceptible (MHS) porcine heavy SR exhibits an altered Ca2+ dependenc...

Objective: Cinnamaldehyde may be responsible for some health benefits of cinnamon such as its neuroprotective effects. We aimed to investigate the cinnamaldehyde neuroprotective effects against amyloid beta (Aβ) in neuronal SHSY5Y cells and evaluate the contribution of N-methyl-D-aspartate (NMDA), ryanodine, and adenosine receptors and glycogen ...

1.1 Size and Evolution The ryanodine receptor (RyR) is a selective Ca release channel that is localized to the endoplasmic reticulum (ER) in both excitable and non-excitable cells. The RyR owes its name to the plant alkaloid and high affinity ligand ryanodine. The functional RyR exists as a tetramer composed of a single unit of approximately 565kDa. To date, it is the largest known ion channel....