Time course of effect of piperazine citrate on the electrocardiogram of the rat

Ventricular fibrillation-induced cardiac arrest in the rat as a model of global cerebral ischemia

Cardiopulmonary arrest remains one of the leading causes of death and disability in Western countries. Although ventricular fibrillation (VF) models in rodents mimic the "square wave" type of insult (rapid loss of pulse and pressure) commonly observed in adult humans at the onset of cardiac arrest (CA), they are not popular because of the complicated animal procedure, poor animal survival and thermal injury. Here we present a modified, simple, reliable, ventricular fibrillation-induced rat model of CA that will be useful in studying mechanisms of CA-induced delayed neuronal death as well as the efficacy of neuroprotective drugs. CA was induced in male Sprague Dawley rats using a modified method of von Planta et al. In brief, VF was induced in anesthetized, paralyzed, mechanically ventilated rats by an alternating current delivered to the entrance of the superior vena cava into the heart. Resuscitation was initiated by administering a bolus injection of epinephrine and sodium bicarbonate followed by mechanical ventilation and manual chest compressions and countershock with a 10-J DC current. Neurologic deficit score was higher in the CA group compared to the sham group during early reperfusion periods, suggesting brain damage. Significant damage in CA1 hippocampus (21% normal neurons compared to control animals) was observed following histopathological assessment at seven days of reperfusion. We propose that this method of VF-induced CA in rat provides a tool to study the mechanism of CA-induced neuronal death without compromising heart functions.

Impact of subchronic administration of piperazine citrate on the electrocardiogram of the rat

The effect of piperazine citrate on the electrocardiogram of the rat after treatment with piperazine citrate at 30, 60, and 100 mg/kg body weight for 16 weeks was investigated. The results were compared with a control group. There was prolongation of P-R, Q-Tc, and J-T intervals, whereas the QRS interval remained virtually unchanged. The heart rate, on the other hand, decreased in the groups that received piperazine citrate. The average heart rate in the control group was 334 ± 17.20 beats/min. In the group of rats that received the three doses of piperazine, the average heart rate at the end of a 15-minute observation period was 308 ± 3.74 beats/min, 302 ± 16.55 beats/min, and 312 ± 13.93 beats/min, respectively, and none of the values was statistically significant compared with the control. The P-R interval showed statistically significant increases in the groups treated with the three doses of piperazine over the control group. In both the 30- and 60-mg/kg groups, the average P-R interval was 92.0 ± 0.5, which was statistically significant when compared with the control average of 80.0 ± 0.00 (P = 0.0427). For the 100-mg/kg group, the average P-R interval was 96.0 ± 0.4 ms. The difference between this value and the control average was equally statistically significant (P = 0.0043). Both the Q-Tc and J-T intervals also showed statistically significant increases in the piperazine-treated groups and the P values compared with the control group were very similar. Even at the very high dose of 100 mg/kg given two times daily for 16 weeks, piperazine citrate appeared quite safe to the rat heart because it did not provoke any cardiac dysrhythmic phenomenon on the surface electrocardiogram.