Cardiac chamber-specific beta-adrenoceptor regulation and sympathetic innervation.

We assessed by radioligand binding techniques the effect of cardiac failure on beta-adrenoceptor density in 5 hearts from patients undergoing repeat transplantation and 5 normal (unused donor) hearts. Right ventricular total and subtype beta-adrenoceptors in the denervated repeat-transplant hearts were down-regulated compared with the normally innervated controls. Within the denervated hearts, beta 1-adrenoceptors were selectively down-regulated in the right ventricle compared with the left ventricle. Tissue noradrenaline content confirmed sympathetic denervation in the transplanted hearts. Thus, regional sympathetic innervation is not necessary for chamber-specific beta-adrenoceptor down-regulation; other mechanisms for this process should be sought.