Restoration of mean arterial pressure in endotoxic shock by meptazinol. Contributions from lysosomal membrane stabilisation, opiate antagonism and noradrenaline release.

Meptazinol elevated mean arterial pressure in rats which had been treated with endotoxin. The drug also reduced the titer of circulating lysosomal enzymes. This effect was secondary to the restoration of mean arterial pressure (MAP). In vitro, meptazinol stabilised lysosomal membranes, increased noradrenaline release and interacted with the opiate receptor (naloxone-binding site) as an antagonist. The relevant contributions of these phenomena to the restoration of MAP are discussed.