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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

Basal QT Interval and QT as Bazett’s Formula Normalized (QTcn) in Each Animal GroupsData are presented as mean ± SD (n = 7 to 8 for each group); *, P < 0.05 versus tea group; †, P < 0.01 versus control group; ‡; P < 0.001 versus control group; •, P < 0.01 versus tea group; #, P < 0.01 versus control and tea groups. Control, control group; T, black tea group; N, nicotine group; N + T, nicotine + black tea group.
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fig20945: Basal QT Interval and QT as Bazett’s Formula Normalized (QTcn) in Each Animal GroupsData are presented as mean ± SD (n = 7 to 8 for each group); *, P < 0.05 versus tea group; †, P < 0.01 versus control group; ‡; P < 0.001 versus control group; •, P < 0.01 versus tea group; #, P < 0.01 versus control and tea groups. Control, control group; T, black tea group; N, nicotine group; N + T, nicotine + black tea group.

Mentions: The RR, PR, and QRS intervals did not show significant difference among animal groups. However, pretreatment with tea and nicotine, alone or in combination, was associated with degrees of QTcn and JT prolongation (Table 1 and Figure 1). The QTcn significantly increased in nicotine group (P < 0.01 and P < 0.05 versus control and Tea group, respectively) and N + T group (P < 0.01 compared with control and tea groups). Prolongation of the JT interval was significant in all groups in comparison with control group (P < 0.05 for tea, and P < 0.01 for nicotine and N + T groups). As shown in Table 1 and Figure 1, combination of tea and nicotine showed additive incremental effects on these parameters.


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)

Basal QT Interval and QT as Bazett’s Formula Normalized (QTcn) in Each Animal GroupsData are presented as mean ± SD (n = 7 to 8 for each group); *, P < 0.05 versus tea group; †, P < 0.01 versus control group; ‡; P < 0.001 versus control group; •, P < 0.01 versus tea group; #, P < 0.01 versus control and tea groups. 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

fig20945: Basal QT Interval and QT as Bazett’s Formula Normalized (QTcn) in Each Animal GroupsData are presented as mean ± SD (n = 7 to 8 for each group); *, P < 0.05 versus tea group; †, P < 0.01 versus control group; ‡; P < 0.001 versus control group; •, P < 0.01 versus tea group; #, P < 0.01 versus control and tea groups. Control, control group; T, black tea group; N, nicotine group; N + T, nicotine + black tea group.
Mentions: The RR, PR, and QRS intervals did not show significant difference among animal groups. However, pretreatment with tea and nicotine, alone or in combination, was associated with degrees of QTcn and JT prolongation (Table 1 and Figure 1). The QTcn significantly increased in nicotine group (P < 0.01 and P < 0.05 versus control and Tea group, respectively) and N + T group (P < 0.01 compared with control and tea groups). Prolongation of the JT interval was significant in all groups in comparison with control group (P < 0.05 for tea, and P < 0.01 for nicotine and N + T groups). As shown in Table 1 and Figure 1, combination of tea and nicotine showed additive incremental effects on these parameters.

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