BACKGROUNDPreconditioning with remifentanil confers cardioprotection. Since Ca(2+) overload is a precipitating factor of injury, we determined the effects of remefentanil on intracellular Ca(2+) ([Ca(2+)](i)) and its transients induced by electrical stimulation and caffeine, which reflects Ca(2+) handling by Ca(2+) handling proteins, in rat ventricular myocytes.

METHODSFreshly isolated adult male Sprague-Dawley rat myocytes were loaded with Fura-2/AM and [Ca](i) was determined by spectrofluorometry. Remifentanil at 0.1 - 1000 microg/L was administered. Ten minutes after administration, either 0.2 Hz electrical stimulation was applied or 10 mmol/L caffeine was added. The [Ca(2+)](i), and the amplitude, time resting and 50% decay (t(50)) of both transients induced by electrical stimulation (E [Ca(2+)](i)) and caffeine (C [Ca(2+)](i)) were determined.

RESULTSRemifentanil (0.1 - 1000.0 microg/L) decreased the [Ca(2+)](i) in a dose-dependent manner. It also decreased the amplitude of both transients dose-dependently. Furthermore, it increased the time to peak and t(50) of both transients dose-dependently.

CONCLUSIONRemifentanil reduced the [Ca(2+)](i) and suppressed the transients induced by electrical stimulation and caffeine in rat ventricular myocytes.

Animals ; Caffeine ; pharmacology ; Calcium ; metabolism ; Calcium Signaling ; drug effects ; Cells, Cultured ; Electric Stimulation ; Male ; Myocytes, Cardiac ; drug effects ; metabolism ; Piperidines ; pharmacology ; Rats ; Rats, Sprague-Dawley

A proportion of patients experience acute or even prolonged cognitive impairment after surgery, a condition known as postoperative cognitive dysfunction (POCD). It is characterized by impairment in different cognitive domains and neuroinflammation has been implicated as one of the inciting factors as strategies targeting inflammation tend to improve cognitive performance. Siegesbeckia Orientails L. (S. Orientails) is a common Chinese medicinal herb used for managing chronic inflammatory diseases. We investigated if pretreatment with S. Orientails before surgery confers any neuroprotective effects in postoperative animals in terms of reducing inflammation and mitigating cognitive impairment. Three-month-old male C57BL/6N mice were fed different doses of S. Orientails extract for 14 days before they underwent a laparotomy. After cognitive testing they were sacrificed on postoperative day (POD) 3. Our results showed that animals with extract pretreatment demonstrated memory improvement in a dose-dependent manner compared with control. Further, evidence for the attenuation of systemic and neuroinflammation was found in the pretreated animals, along with the inhibition of inflammatory pathways and significantly reduced tau phosphorylation in the hippocampus. Taken together, these results demonstrated a neuroprotective effect of S. Orientails in postoperative animals, indicating a therapeutic potential of S. Orientails in minimizing POCD and the possibility of utilizing this traditional Chinese medicine perioperatively.
Animals ; Asian Continental Ancestry Group ; Cognition Disorders ; Hippocampus ; Humans ; Inflammation* ; Laparotomy ; Male ; Medicine, Chinese Traditional ; Memory ; Mice ; Neuroprotective Agents ; Phosphorylation ; Plants, Medicinal