Effects of 2-Hydroxypropyl-Beta-Cyclodextrin on Cardiovascular Signs of Amitriptyline Poisoning in a Rat Model

Effect of the selective mitochondrial KATP channel opener nicorandil on the QT prolongation and myocardial damage induced by amitriptyline in rats

OBJECTIVES

The aim of this study is to evaluate the protective effect of nicorandil, a selective mitochondrial KATP channel opener, on QT prolongation and myocardial damage induced by amitriptyline.

METHODS

The dose of amitriptyline (intraperitoneal, i.p.) that prolong the QT interval was found 75 mg/kg. Rats were randomized into five groups the control group, amitriptyline group, nicorandil (selective mitochondrial KATP channel opener, 3 mg/kg i.p.) + amitriptyline group, 5-hdyroxydecanoate (5-HD, selective mitochondrial KATP channel blocker, 10 mg/kg i.p.) + amitriptyline group and 5-HD + nicorandil + amitriptyline group. Cardiac parameters, biochemical and histomorphological/immunohistochemical examinations were evaluated. p < 0.05 was accepted as statistically significant.

KEY FINDINGS

Amitriptyline caused statistically significant prolongation of QRS duration, QT interval and QTc interval (p < 0.05). It also caused changes in tissue oxidant (increase in malondialdehyde)/anti-oxidant (decrease in glutathione peroxidase) parameters (p < 0.05), myocardial damage and apoptosis (p < 0.01 and p < 0.001). While nicorandil administration prevented amitriptyline-induced QRS, QT, QTc prolongation (p < 0.05), myocardial damage and apoptosis (p < 0.05), it did not affect the changes in oxidative parameters (p > 0.05).

CONCLUSIONS

Our results suggest that nicorandil, a selective mitochondrial KATP channel opener, plays a protective role in amitriptyline-induced QT prolongation and myocardial damage. Mitochondrial KATP channel opening and anti-apoptotic effects may play a role in the cardioprotective effect of nicorandil.

General anesthesia and electrocardiographic parameters in in vivo experiments involving rats

In in vivo cardiovascular or toxicological studies involving rat models, changes in selected electrocardiographic (ECG) parameters are monitored after various interventions to assess the origin and development of heart rhythm disorders. Each ECG parameter has diagnostic significance; as such, commonly evaluated ECG parameters, including heart rate, PR interval, P wave duration, P wave amplitude, QRS complex, QT and QTc interval duration, R wave and T wave amplitude, of rats under various types of general anesthesia were the focus of this study. Studies that performed in vivo cardiovascular or toxicological experiments in rats were retrieved from a search of the Web of Science database for articles published mainly between 2000 and 2021. In total, the search retrieved 123 articles. ECG parameters that were reported as baseline or control values were summarized and averages with ranges were calculated. It is important to be cautious when interpreting results and, in discussions addressing the mechanisms underlying a given type of arrhythmia, acknowledge that initial ECG parameters may already be affected to some extent by the general anesthesia as well as by sex and the time of day the experiments were performed.

Squarticles as the nanoantidotes to sequester the overdosed antidepressant for detoxification

The increasing death rate caused by drug overdose points to an urgent demand for the development of novel detoxification therapy. In an attempt to detoxify tricyclic antidepressant overdose, we prepared a lipid nanoemulsion, called squarticles, as the nanoantidote. Squalene was the major lipid matrix of the squarticles. Here, we present the animal study to investigate both the pharmacokinetic and pharmacodynamic effects of squarticles on amitriptyline intoxication. The anionic and cationic squarticles had average diameters of 97 and 122 nm, respectively. Through the entrapment study, squarticles could intercept 40%–50% of the amitriptyline during 2 h with low leakage after loading into the nanoparticles. The results of isothermal titration calorimetry demonstrated greater interaction of amitriptyline with the surface of anionic squarticles (K_a =28,700) than with cationic ones (K_a =5,010). Real-time imaging showed that intravenous administration of anionic squarticles resulted in a prolonged retention in the circulation. In a rat model of amitriptyline poisoning, anionic squarticles increased the plasma drug concentration by 2.5-fold. The drug uptake in the highly perfused organs was diminished after squarticle infusion, indicating the lipid sink effect of bringing the entrapped overdosed drug in the tissues back into circulation. In addition, the anionic nanosystems restored the mean arterial pressure to near normal after amitriptyline injection. The survival rate of overdosed amitriptyline increased from 25% to 75% by treatment with squarticles. Our results show that the adverse effects of amitriptyline intoxication could be mitigated by administering anionic squarticles. This lipid nanoemulsion is a potent antidote to extract amitriptyline and eliminate it.