Low density lipoprotein modulation of porcine coronary artery contractile response to histamine

Right coronary artery ring segments from miniature swine contracted to histamine with a force and sensitivity comparable to that reported for human right coronary artery ring segments. When the ring segments were suspended in preparations of human low density lipoprotein (LDL) the contractility was reduced. With denuded rings the contractility was significantly lower in the LDL at 1.1 X 10(-4) M histamine. With intact rings significantly less tension was generated in the LDL at concentrations greater than 6 X 10(-5) M histamine. Thus LDL attenuates the contractile response of the porcine right coronary artery to histamine.