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Arrhythmogenic Risk Assessment Following Four-Week Pretreatment With Nicotine and Black Tea in Rat.

Joukar S, Sheibani V, Koushesh F, Ghasemipoor Afshar E, Ghorbani Shahrbabaki S - Res Cardiovasc Med (2015)

Bottom Line: On day 29, aconitine was infused intravenously for induction of cardiac arrhythmia.The latency for the first VT event was significantly longer in the all test groups, but VF latency was significant only in tea and nicotine groups compared with control group (P < 0.05 and P < 0.01, respectively).Threshold dose of aconitine for inducing VT and VF increased in all test groups, but only VT showed a significant difference in comparison to the control group (P < 0.001).The findings suggest that sub-chronic consumption of nicotine or black tea alone with appropriate doses could potentially be antiarrhythmic and its combination regimen does not increase the risk of fatal ventricular arrhythmias during four-week consumption period in rats.

View Article: PubMed Central - PubMed

Affiliation: Physiology Research Center, Institute of Neuropharmacology, Kerman University of Medical Sciences, Kerman, IR Iran ; Neuroscience Research Center, Institute of Neuropharmacology, Kerman University of Medical Sciences, Kerman, IR Iran ; Department of Physiology and Pharmacology, Kerman University of Medical Sciences, Kerman, IR Iran.

ABSTRACT

Background: There is the controversy concerning the main component of tobacco, which is responsible for its arrhythmogenesis. In addition, there is the lack of adequate information about the influence of combination of black tea and nicotine on heart rhythm.

Objectives: This study aimed to examine whether pretreatment with black tea and nicotine could modulate the susceptibility to lethal ventricular arrhythmias.

Materials and methods: Animals were randomized to control, black tea, nicotine, and black tea plus nicotine groups. Test groups were treated with black tea brewed (orally) and nicotine (2 mg/kg, subcutaneous), alone and in combination for four weeks. On day 29, aconitine was infused intravenously for induction of cardiac arrhythmia.

Results: In comparison with the control group, each of tea and nicotine significantly decreased the duration of the ventricular tachycardia (VT) plus ventricular fibrillation (VF) and the score of arrhythmia severity (P < 0.05 and P < 0.01, respectively,). The latency for the first VT event was significantly longer in the all test groups, but VF latency was significant only in tea and nicotine groups compared with control group (P < 0.05 and P < 0.01, respectively).Threshold dose of aconitine for inducing VT and VF increased in all test groups, but only VT showed a significant difference in comparison to the control group (P < 0.001).

Conclusions: The findings suggest that sub-chronic consumption of nicotine or black tea alone with appropriate doses could potentially be antiarrhythmic and its combination regimen does not increase the risk of fatal ventricular arrhythmias during four-week consumption period in rats.

No MeSH data available.


Related in: MedlinePlus

The Effects of Four-Week Pretreatment of Nicotine and Black Tea on Latency, Times From the Onset of Aconitine Infusion to the first VT and VF (A), and Threshold Dose of Aconitine for Induction of VT and VF (B)Data are presented as mean ± SD, (n, 7 to 8 for each group); •, P < 0.001 versus control group; *, P < 0.05 versus control group; **, P < 0.01 versus control group; Control, control group; T, black tea group; N, nicotine group; N + T, nicotine + black tea group.
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fig20947: The Effects of Four-Week Pretreatment of Nicotine and Black Tea on Latency, Times From the Onset of Aconitine Infusion to the first VT and VF (A), and Threshold Dose of Aconitine for Induction of VT and VF (B)Data are presented as mean ± SD, (n, 7 to 8 for each group); •, P < 0.001 versus control group; *, P < 0.05 versus control group; **, P < 0.01 versus control group; Control, control group; T, black tea group; N, nicotine group; N + T, nicotine + black tea group.

Mentions: Four-week consumption of black tea resulted in significant increase in the number of PVCs when compared with the control group (P < 0.01) (Figure 2 A). Although tea and nicotine alone or in combination had no significant effect on the numbers of VT + VF or VF (Figure 2, B), but tea and nicotine individually decreased the VT + VF duration (P < 0.001 for tea group and P < 0.05 for nicotine group compared with control group) (Figure 2 C). The latency times from the onset of aconitine infusion to the first VT and VF were measured in the different groups. The latency for first VT event was significantly longer in the tea and nicotine groups (P < 0.001) as well as N + T group (P < 0.01) than in control group. This pattern was repeated for VF latency, but it was only significant in tea group (P < 0.01) and nicotine group (P < 0.05) versus control group (Figure 3 A). In addition, threshold dose of aconitine for induction of VT and VF was enhanced in all test groups, but it was significant only for VT (P < 0.001 whenever all groups were compared with the control group) (Figure 3 B). The score of arrhythmia severity was diminished in tea group (P < 0.001) and nicotine group (P < 0.01) compared to the control group. However, in presence of combination of tea and nicotine, the scores of lethal arrhythmia showed no significant difference in comparison with control group (Figure 2 D).


Arrhythmogenic Risk Assessment Following Four-Week Pretreatment With Nicotine and Black Tea in Rat.

Joukar S, Sheibani V, Koushesh F, Ghasemipoor Afshar E, Ghorbani Shahrbabaki S - Res Cardiovasc Med (2015)

The Effects of Four-Week Pretreatment of Nicotine and Black Tea on Latency, Times From the Onset of Aconitine Infusion to the first VT and VF (A), and Threshold Dose of Aconitine for Induction of VT and VF (B)Data are presented as mean ± SD, (n, 7 to 8 for each group); •, P < 0.001 versus control group; *, P < 0.05 versus control group; **, P < 0.01 versus control group; Control, control group; T, black tea group; N, nicotine group; N + T, nicotine + black tea group.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4588709&req=5

fig20947: The Effects of Four-Week Pretreatment of Nicotine and Black Tea on Latency, Times From the Onset of Aconitine Infusion to the first VT and VF (A), and Threshold Dose of Aconitine for Induction of VT and VF (B)Data are presented as mean ± SD, (n, 7 to 8 for each group); •, P < 0.001 versus control group; *, P < 0.05 versus control group; **, P < 0.01 versus control group; Control, control group; T, black tea group; N, nicotine group; N + T, nicotine + black tea group.
Mentions: Four-week consumption of black tea resulted in significant increase in the number of PVCs when compared with the control group (P < 0.01) (Figure 2 A). Although tea and nicotine alone or in combination had no significant effect on the numbers of VT + VF or VF (Figure 2, B), but tea and nicotine individually decreased the VT + VF duration (P < 0.001 for tea group and P < 0.05 for nicotine group compared with control group) (Figure 2 C). The latency times from the onset of aconitine infusion to the first VT and VF were measured in the different groups. The latency for first VT event was significantly longer in the tea and nicotine groups (P < 0.001) as well as N + T group (P < 0.01) than in control group. This pattern was repeated for VF latency, but it was only significant in tea group (P < 0.01) and nicotine group (P < 0.05) versus control group (Figure 3 A). In addition, threshold dose of aconitine for induction of VT and VF was enhanced in all test groups, but it was significant only for VT (P < 0.001 whenever all groups were compared with the control group) (Figure 3 B). The score of arrhythmia severity was diminished in tea group (P < 0.001) and nicotine group (P < 0.01) compared to the control group. However, in presence of combination of tea and nicotine, the scores of lethal arrhythmia showed no significant difference in comparison with control group (Figure 2 D).

Bottom Line: On day 29, aconitine was infused intravenously for induction of cardiac arrhythmia.The latency for the first VT event was significantly longer in the all test groups, but VF latency was significant only in tea and nicotine groups compared with control group (P < 0.05 and P < 0.01, respectively).Threshold dose of aconitine for inducing VT and VF increased in all test groups, but only VT showed a significant difference in comparison to the control group (P < 0.001).The findings suggest that sub-chronic consumption of nicotine or black tea alone with appropriate doses could potentially be antiarrhythmic and its combination regimen does not increase the risk of fatal ventricular arrhythmias during four-week consumption period in rats.

View Article: PubMed Central - PubMed

Affiliation: Physiology Research Center, Institute of Neuropharmacology, Kerman University of Medical Sciences, Kerman, IR Iran ; Neuroscience Research Center, Institute of Neuropharmacology, Kerman University of Medical Sciences, Kerman, IR Iran ; Department of Physiology and Pharmacology, Kerman University of Medical Sciences, Kerman, IR Iran.

ABSTRACT

Background: There is the controversy concerning the main component of tobacco, which is responsible for its arrhythmogenesis. In addition, there is the lack of adequate information about the influence of combination of black tea and nicotine on heart rhythm.

Objectives: This study aimed to examine whether pretreatment with black tea and nicotine could modulate the susceptibility to lethal ventricular arrhythmias.

Materials and methods: Animals were randomized to control, black tea, nicotine, and black tea plus nicotine groups. Test groups were treated with black tea brewed (orally) and nicotine (2 mg/kg, subcutaneous), alone and in combination for four weeks. On day 29, aconitine was infused intravenously for induction of cardiac arrhythmia.

Results: In comparison with the control group, each of tea and nicotine significantly decreased the duration of the ventricular tachycardia (VT) plus ventricular fibrillation (VF) and the score of arrhythmia severity (P < 0.05 and P < 0.01, respectively,). The latency for the first VT event was significantly longer in the all test groups, but VF latency was significant only in tea and nicotine groups compared with control group (P < 0.05 and P < 0.01, respectively).Threshold dose of aconitine for inducing VT and VF increased in all test groups, but only VT showed a significant difference in comparison to the control group (P < 0.001).

Conclusions: The findings suggest that sub-chronic consumption of nicotine or black tea alone with appropriate doses could potentially be antiarrhythmic and its combination regimen does not increase the risk of fatal ventricular arrhythmias during four-week consumption period in rats.

No MeSH data available.


Related in: MedlinePlus