Studies on bacteria have suggested that morphine-like drugs have effects on the cell membrane. To determine the effect of this class of drugs on a mammalian cell, we selected the rabbit peritoneal exudate granulocyte, which undergoes striking membrane changes during phagocytosis. We examined the effect in vitro of the morphine analogue, levorphanol on phagocytosis and metabolism by granulocytes incubated with and without polystyrene particles or live Escherichia coli. Levorphanol (1 or 2 mmoles/liter) decreased: (a) acylation of lysolecithin or lysophosphatidylethanolamine in the medium (which is stimulated about two-fold during phagocytosis) both at rest (40%) and during phagocytosis (60%); (b) uptake of latex particles and Escherichia coli, as judged by electron microscopy; (c) killing of live Escherichia coli (10-fold); (d) 14CO2 production from glucose-1-14C during phagocytosis by at least 80%; (e) K+ content of granulocytes (35%); (f) oxidation of linoleate-1-14C by 50%, and its incorporation into triglyceride by more than 80%. However, levorphanol stimulated 2 to 3-fold the incorporation of linoleate-1-14C or palmitate-1-14C into several phospholipids. Glucose uptake, lactate production, and adenosine triphosphate (ATP) content are not affected by the drug. Thus, levorphanol does not appear to exert its effects through generalized metabolic suppression.
Nancy Wurster, Peter Elsbach, Eric J. Simon, Penelope Pettis, Sharon Lebow