Adenosine receptor blockade impairs the ability of rat pups to autoresuscitate from primary apnea during repeated exposure to hypoxia (LB790)

Autoresuscitation (AR) failure from hypoxic-induced apnea by gasping has been suggested to play a role in sudden infant death. Little is known, however, about the factors that influence gasping and its ability to effect autoresuscitation in the newborn. The present experiments were carried out on 18 5-6 day-old rat pups to investigate the role of adenosine acting via A1 receptors in mediating AR from hypoxic-induced apnea by gasping. DPCPX (20 mg/kg; a selective adenosine A1-receptor antagonist) attenuated the heart rate response to hypoxia and decreased the number of hypoxic episodes tolerated before AR failure (DPCPX 10±2 (n=9) versus vehicle 17±5 (n=9); p<0.001). Following vehicle, death was preceded most often by AV dissociation whereas following DPCPX death was preceded most often by an isoelectric electrocardiogram. Thus, our data provide evidence that adenosine acting via A1 receptors plays an important role in promoting AR from hypoxic-induced apnea by gasping.Grant Funding Source: CIHR