HETEROGENEITY OF HUMAN MAST-CELLS AND BASOPHILS IN RESPONSE TO MUSCLE-RELAXANTS

The authors studied the effects of increasing concentrations (10(-5) - 10(-3) M) of four muscle relaxants (succinylcholine, d-tubocurarine, vecuronium, and atracurium) on histamine release from peripheral blood basophils and mast cells isolated from human lung parenchyma, skin tissues, and heart fragments. Basophil granulocytes released less than 5% of their histamine content when incubated with any one of the muscle relaxants tested. In contrast, mast cells showed a significant heterogeneity in response to different muscle relaxants. Succinylcholine did not induce histamine release from any type of mast cell, and only high concentrations of d-tubocurarine (10(-3) M) caused histamine release from skin and lung mast cells. Vecuronium concentration-dependently induced histamine release from skin and lung-but not from heart mast cells-to a maximum of 7.2 +/- 2.1% and 4.9 +/- 1.4%, respectively. Atracurium concentration-dependently caused significantly histamine release from skin and lung mast cells to a maximum of 46.2 +/- 15.1% and 30.6 +/- 6.0%, respectively. Atracurium (5 x 10(-5) -2 x 10(-4) M) also induced histamine release from heart mast cells. The histamine release process from both lung and skin mast cells caused by atracurium and vecuronium was extremely rapid (t1/2 = < 1 min). The releasing activity of atracurium and vecuronium on lung and skin mast cells was not reduced, and not abolished, by lowering the temperature of the incubation buffer to 22-degrees-C and 4-degrees-C. Extracellular calcium did not affect the capacity of atracurium and vecuronium to induce histamine release from lung and skin mast cells. The releasing activity of atracurium on lung and skin mast cells was not reduced by metabolic impairment caused by preincubation with 2-deoxy-D-glucose plus antimycin A. Furthermore, this release process was not reduced by preincubation of lung and skin mast cells at 47-degrees-C for 20 min. These results confirm that there are functional differences between human basophils and mast cells and among mast cells isolated from different anatomic sites in response to the four muscle relaxants tested.