Papel de la disfunción endotelial en la respuesta a la cocaína del flujo coronario y la contractilidad miocárdica
ENGLISH ABSTRACT: Role of endotelial dysfuntion on cocaine effects in coronary flow and myocardial contractility 1. Hypothesis Cocaine has been associated with myocardial ischaemia and left ventricular dysfunction. Whether nitric oxide (NO) inhibition may potentiate the effects of cocaine on coronary circulation and ventricular function is still unknown. 2.Material and methods In order to test this hipótesis, 57 pentobarbital-anaesthetized pigs were instrumenteted for systolic blood pressure, coronary blood flow, left ventricular dp/dt, cardiac output, left ventricular end-diastolic and end-systolic leghts and shortening fraction. The pigs were randomized into six groups: control group: i.v. saline(n=5); group 1: cocaine, 10 mg kg-1 over 20 min (n=17); group 2 : the same dosis of cocaine 30 min after i.c. L-NAME 20 mg/kg min-1 infusion( n=16); group 3: The same dosis of cocaine after the proximal left anterior descending (LAD) flow was reduced to around 20% of the basl value by means of a mechanical occluder (n=9); group 4: the same dosis of cocaine after i.c. simultaneously L-arginina and L-NAME infusion (n=5); group 5: the same dosis of cocaine after simultaneously i.c. L-NAME and nitroglicerine infusion. 3.Results Cocaine i.v. did not change the coronary blood flow, while it induced a significant reduction in cardiac output, left ventricular dp/dt and shortening fraction. When cocaine was administered after L-NAME infused i.c. a significant more severe reduction of the shortening fraction was induced; this effect was abolished by simultaneosus perfusion of L-arginine and NAG i.c.. The results when cocaine was administered after 20% LAD flow reduction by mechanical occluder did not differ from those of cocaine alone. 4.Conclusions NO inhibition intesifies the cocaine-induced left ventricular funtion.
Advisor:Sanz Romero, Ginés; Roig Minguell, Eulalia
School:Universitat de Barcelona
Source Type:Master's Thesis
Date of Publication:12/11/2003