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Immunosuppressive effects of benzodiazepines
911
phosphates and an influx of extracellular Ca++. We have prepared resting lymphocytes from the peripheral blood of healthy volunteers and stimulated them with the mitogens concanavalin A and phytohemagglutinin. Inositol phaphate generation was assessed after prelabeling with [3H]myo-inositol, subsequent mitogen exposure, and then determination of generated inositol phosphates by ion exchange chromatography. Elevations of intracellular Ca++ were monitored by the fluorescent indicator Fura-2. In the presence of verapamil, mitogen-stimulated inositol phosphate generation was markedly reduced. Similarly, verapamil (100 PM) inhibited phytohemagglutinin and concanavalin A-stimulated Ca++ increases by 26 f 6% and 50 f 68, respectively. In the second part of our studies, we trP%ted 9 healthy volunteers with verapamil (240 mg bid for 1 week). Circulating lymphocyte subsets were assessed by immunofluorescence, and in vitro responsiveness to mitogenic stimulation was determined as [%I]thymidine incorporation in response to the mitogen concanavalin A. The total number of circulating lymphocytes, of Thclper-,Tsupp~s~~/cy~otoxic and of natural killer cells was not significantly altered after verapamil treatment. The [‘Hlthymidine incorporation in response to concanavalin A (as a parameter for the ability of lymphocytes to proliferate) was sunilar before and after 1 week of treatment with verapamil. V,‘e conclude that high concentrations of verapamil can inhibit lymphocyte activation in vim; therapeutic doses of verspamil in vivo do not affect circulating lymphocyte numbers or their responsiveness to mitogens.
Chandy, KG. et al., 1984, J. Exp. Med. 160. -2: Nobrega, A.F. et al.. 1986, Clin. Exp. Immunol. 65: 159. Wagner, K. et al., 1986, Transplant. Proc. 18: 1269. Sumpio, B. et al., 1987. Surgery 315.
El
P.tu.255
Schlumpf * Institute
*, M., Lichtensteiger
*, W. and Ramseier, H.R.
of Pharmacology and Znstitute of Immunology and Virology, Universityof Ziirich, Erich,
SwitrerJand
Cellular immune responses were found to be depressed in male and female offspring of diazepam treated dams (Schlumpf et al., 1989). The lymphocyte proliferative response (Ramseier, 1957) was t’aund to be depressed as a consequence of low dose diazepam treatment (1.25 mgjkg) from GD (gestational day) 14 to GD 20. Diazepam treatment of the pregnant dam from GD 16 to GD 20, at a time when peripheral benzodiazepine sites (PBPZ) are present in the fetus, also resulted in depressed lymphocyte proliferative activity, whereas drug exposure during early fetal life, from GD 12 to GD 16, had no depressive effects on the immune system. Clonazepam, a benzodiazepine with high affinity for the central and Ro 5-4864 with high affinity for the peripheral type benzodiazepine receptor, administered to the pregnant dam also inhibited T cell proliferative response in offspring significantly. In adult rats Conconavalin A (ConA) stimulated T cell proliferation is considerably reduced in presence of 10 micromolar diazepam, clonazepam and Ro 5-4864. Benzodiazepines also strongly inhibit ConA stimulated T cell proliferation in adult mice of different strains (BlO.BR, C57BL/lO, BlO.D2/n and A.SW). In addition, the proliferative response to ConA of a T helper cell line (DlO G4.1) is reduced in presence of different benzodiazepine agonists (clonazepam, diazepam, Ro 5-4864), even in the absence of macrophages. Preliminary results also suggest a reduced LPS (lipopolysaccharid) induced proliferation of B cells under the influence of different benzodiazepines. Interleukin-1 (IL-l) production by rat macrophages appears to be stimulated in the presence of the following benzodiazepine agonists: diazepam, clonazepam and Ro 5-4864 at micromolar concentrations. This data show that benzodiazepines are capable of interfering with the function of several cells of the immune system.
References Ramseier, H., Cell. Immunol. 110, 95-106 (1987). Sc’hlumpf, M., H. Ramseier, W. Lichtensteiger, Life Sci. 44, 493-501 (1989).
phosphates and an influx of extracellular Ca++. We have prepared resting lymphocytes from the peripheral blood of healthy volunteers and stimulated them with the mitogens concanavalin A and phytohemagglutinin. Inositol phaphate generation was assessed after prelabeling with [3H]myo-inositol, subsequent mitogen exposure, and then determination of generated inositol phosphates by ion exchange chromatography. Elevations of intracellular Ca++ were monitored by the fluorescent indicator Fura-2. In the presence of verapamil, mitogen-stimulated inositol phosphate generation was markedly reduced. Similarly, verapamil (100 PM) inhibited phytohemagglutinin and concanavalin A-stimulated Ca++ increases by 26 f 6% and 50 f 68, respectively. In the second part of our studies, we trP%ted 9 healthy volunteers with verapamil (240 mg bid for 1 week). Circulating lymphocyte subsets were assessed by immunofluorescence, and in vitro responsiveness to mitogenic stimulation was determined as [%I]thymidine incorporation in response to the mitogen concanavalin A. The total number of circulating lymphocytes, of Thclper-,Tsupp~s~~/cy~otoxic and of natural killer cells was not significantly altered after verapamil treatment. The [‘Hlthymidine incorporation in response to concanavalin A (as a parameter for the ability of lymphocytes to proliferate) was sunilar before and after 1 week of treatment with verapamil. V,‘e conclude that high concentrations of verapamil can inhibit lymphocyte activation in vim; therapeutic doses of verspamil in vivo do not affect circulating lymphocyte numbers or their responsiveness to mitogens.
Chandy, KG. et al., 1984, J. Exp. Med. 160. -2: Nobrega, A.F. et al.. 1986, Clin. Exp. Immunol. 65: 159. Wagner, K. et al., 1986, Transplant. Proc. 18: 1269. Sumpio, B. et al., 1987. Surgery 315.
El
P.tu.255
Schlumpf * Institute
*, M., Lichtensteiger
*, W. and Ramseier, H.R.
of Pharmacology and Znstitute of Immunology and Virology, Universityof Ziirich, Erich,
SwitrerJand
Cellular immune responses were found to be depressed in male and female offspring of diazepam treated dams (Schlumpf et al., 1989). The lymphocyte proliferative response (Ramseier, 1957) was t’aund to be depressed as a consequence of low dose diazepam treatment (1.25 mgjkg) from GD (gestational day) 14 to GD 20. Diazepam treatment of the pregnant dam from GD 16 to GD 20, at a time when peripheral benzodiazepine sites (PBPZ) are present in the fetus, also resulted in depressed lymphocyte proliferative activity, whereas drug exposure during early fetal life, from GD 12 to GD 16, had no depressive effects on the immune system. Clonazepam, a benzodiazepine with high affinity for the central and Ro 5-4864 with high affinity for the peripheral type benzodiazepine receptor, administered to the pregnant dam also inhibited T cell proliferative response in offspring significantly. In adult rats Conconavalin A (ConA) stimulated T cell proliferation is considerably reduced in presence of 10 micromolar diazepam, clonazepam and Ro 5-4864. Benzodiazepines also strongly inhibit ConA stimulated T cell proliferation in adult mice of different strains (BlO.BR, C57BL/lO, BlO.D2/n and A.SW). In addition, the proliferative response to ConA of a T helper cell line (DlO G4.1) is reduced in presence of different benzodiazepine agonists (clonazepam, diazepam, Ro 5-4864), even in the absence of macrophages. Preliminary results also suggest a reduced LPS (lipopolysaccharid) induced proliferation of B cells under the influence of different benzodiazepines. Interleukin-1 (IL-l) production by rat macrophages appears to be stimulated in the presence of the following benzodiazepine agonists: diazepam, clonazepam and Ro 5-4864 at micromolar concentrations. This data show that benzodiazepines are capable of interfering with the function of several cells of the immune system.
References Ramseier, H., Cell. Immunol. 110, 95-106 (1987). Sc’hlumpf, M., H. Ramseier, W. Lichtensteiger, Life Sci. 44, 493-501 (1989).