Simultaneous blockade of the cyclooxygenase and L-arginine-nitric oxide pathways prevents the antiarrhythmic effects of classical preconditioning (part 6)

RESULTS
Hemodynamic effects of meclofenamate, L-NAME and coronary artery occlusion: The hemodynamic effects of meclofenamate and L-NAME are summarized in Table 1. Meclofenamate administration resulted in no sufficient changes in any hemodynamic parameter. However, infusion of L-NAME significantly increased arterial blood pressure and LV systolic pressure, and reduced heart rate, LV end-diastolic pressure, and both positive and negative LV dP/dt (Table 1). Following coronary artery occlusion, changes in diastolic and mean arterial blood pressures were somewhat more marked after this drug treatment. Reductions in positive and negative LV dP/dt were similar in both groups.

The protocol was as follows (Figure 1).

Simultaneous blockade of the cyclooxygenase and L-arginine-nitric oxide pathways prevents the antiarrhythmic effects of classical preconditioning You will always be able to buy the required amount of medicine you need at this wonderful and fully licensed pharmacy that can take good care of you, no matter if you need cheap ventolin inhalers at large amounts or just a bit of it to finish your treatment.

Figure 1 Experimental protocol for studies designed to evaluate the respective roles of nitric oxide and prostanoids in protection against ventricular arrhythmias by ischemic preconditioning (PC). PC was induced by two 5 min coronary artery occlusions separated by a 20 min reperfusion period; the control occlusion, 25 mins in duration, was begun 20 mins after the end ofthe second PC occlusion or afterPC but before the prolonged ischemic period. ic Intracoronary injection; iv Intravenous injection; L-NAME NG-nitro-L-arginine methyl ester; MF Meclofenamate 

TABLE 1 Hemodynamic effects of meclofenamate (2 mg/kg intravenously) and L-NAME (5 mg/kg intracoronary injection)

Beforemeclofenamate Meclofenamate Change BeforeL-NAME L-NAME Change
Arterial blood pressure (mmHg)
Systolic 121±8 127±7 6±2 125±8 141±8 16±3*
Diastolic 78±4 82±5 4±3 80±5 105±6 26±2*
Mean 92±5 97±6 5±2 95±5 117±7 22±2*
LV systolic pressure (mmHg) 125±7 130±7 5±2 129±7 147±4 18±3*
LVEDP (mmHg) 6±1 6±1 0 7±1 8±1 1±1
Heart rate (beats/min) 151±9 01±35

1

2±1 153±10 145±9 -8±2*
LV dP/dtmax (mmHg/s)
Positive 2746±162 2863±204 118±78 2817±204 3036±231 218±126
Negative 2560±114 2752±97 192±66 2674±100 2845±121 171±119

*P<0.05; n = 19. LV Left ventricle; L-NAME

Category: Cardiology

Tags: Cyclooxygenase pathway, Ischemic preconditioning, L-arginine-nitric oxide pathway

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