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T McIntyre

Publications and source records attributed to T McIntyre.

7 recordsLinked to original sources
PubMed1992

Ethanol inhibits mitogen-induced calcium mobilization in mouse splenocytes.

Ethanol inhibited the mitogen-induced initial increase in cytoplasmic free-calcium [Ca2+]i in mouse splenocytes. This effect was concentration-dependent, reversible, and observed at pharmacologically relevant concentrations (24-166mM). Other short-chain alcohols such as propanol, butanol, and pentanol also inhibited this mitogen-induced increase in [Ca2+]i. The potencies of these alcohols to produce this effect were highly correlated (r = 0.98, p less than 0.001) with their membrane/buffer partition coefficients. Analysis of mouse splenocyte subpopulations demonstrated that this effect was manifest in both B and T lymphocytes. Within T lymphocyte subpopulations, both CD4+ and CD8+ T cells were affected. These results suggest that the inhibition of [Ca2+]i increase may be an early event mediating ethanol-induced immunosuppression and that this may be a predisposing factor to infection and malignancies associated with alcoholism.

Alcoholism↗
PubMed1991

Morphine-induced thymic hypoplasia is glucocorticoid-dependent.

Mice administered morphine as a s.c. pellet implant exhibit a marked and sustained thymic hypoplasia as well as suppression of T lymphocyte functions. In the present study, the effects of morphine on thymocyte differentiation were characterized. Morphine produced a significant decrease in both the number and proportion of CD4+/CD8+ double positive (DP) cells. The percentage of the CD4+/CD8-, CD4-/CD8+, and CD4-/CD8- double negative subsets in these mice was proportionally increased. Morphine also increased the proportion of cells expressing either the epsilon-chain of the CD3 complex or the IL-2R. The initial reduction in the proportion of DP thymocytes appeared fully recovered by 10 days post-implantation, although the number of DP thymocytes gradually returned to normal over a 3-wk period. Morphine administration resulted in a marked increase in serum corticosterone levels, and a single injection of dexamethasone mimicked the effects of morphine on thymus differentiation. Furthermore, adrenalectomy abolished the morphine-induced decrease in CD4+/CD8+ thymocytes relative to a sham-operated group. The present findings are consistent with the hypothesis that morphine-induced thymic hypoplasia may be mediated by an increase in the circulating levels of corticosterone.

Adrenalectomy↗
PubMed1991

Stress modulates calcium mobilization in immune cells.

Both acute and chronic restraint stress modulated mitogen-induced increases in cytoplasmic free-calcium concentrations ([Ca2+]i) in mouse spleen cells. Dual-color analysis of lymphocyte subpopulations demonstrated that acute (2 hour) restraint stress suppressed mitogen-stimulated increases in [Ca2+]i in CD4+ T cells, but enhanced [Ca2+]i in CD8+ T cells. Chronic restraint stress (2 hours daily for up to 21 days) resulted in a significant suppression of mitogen-stimulated increases in [Ca2+]i in CD4+ T cells at 3 and 7 days, but not at 21 days. CD8+ T cells were unaffected by chronic stress. Chronic stress (for 7 days) had a modest suppressive effect on mitogen-induced Ca2+ responses in B cells. Within T lymphocyte subpopulations, both acute and chronic stress predominantly affected CD4+ T cells, which may induce a functional reversal of the CD4/CD8 ratios in vivo. Such a reversal could result in suppression of a variety of immune responses such as lymphocyte proliferation and antigen-specific antibody production. These findings indicate that the inhibitory effects of stress on calcium mobilization in lymphocytes may be an early event mediating stress-induced immunosuppression.

Acute Disease↗
PubMed1991

Inhibition of calcium mobilization is an early event in opiate-induced immunosuppression.

Morphine administered as a subcutaneous implant inhibits the initial increase in cytoplasmic free-calcium [Ca2+]i induced by mitogens in mouse splenocytes. This effect was not reproduced by incubation of splenocytes with morphine (10(-8)-10(-4) M). Analysis of splenocyte subpopulations demonstrates that this effect was manifest in both B and T cells. However, within T cell subpopulations, CD4+ but not CD8+ cells were affected. Adrenalectomy abolished this effect of morphine in CD4+ T but not CD4-, CD8- spleen cells (most likely Thy 1.2- B cells). Moreover, simultaneous administration of the opiate antagonist naltrexone blocked the effect of morphine in CD4-, CD8- spleen cells, but not in CD4+ T cells. These data indicate that the effects of morphine on mitogen-stimulated increase in [Ca2+]i may be mediated through distinct glucocorticoid-dependent and -independent mechanisms. The morphine-induced inhibition of an increase in [Ca2+]i in immune cells reported here may be an early event mediating opiate-induced immunosuppression.

Animals↗
PubMed1991

t-[35S]butylbicyclophosphorothionate binding under equilibrium and nonequilibrium conditions: differential effects of barbiturates and gamma-aminobutyric acid in the long-sleep and short-sleep selected mouse lines.

Significant differences were demonstrated between the long-sleep (LS) and short-sleep (SS) selected mouse lines in the abilities of barbiturates and gamma-aminobutyric acid (GABA) to inhibit t-[35S]butylbicyclophosphorothionate [( 35S]TBPS) binding to well-washed cerebral cortical membranes. Thus, using phenobarbital to initiate the dissociation of [35S]TBPS, the extent of inhibition was significantly greater in LS mice (but not SS mice) than would be predicted using equilibrium conditions. Pentobarbital had the opposite effect, causing [35S]TBPS to dissociate to a greater extent in SS than LS membranes. [35S]TBPS binding was dissociated from LS and SS membranes by GABA to a greater and lesser extent, respectively, than would be predicted from equilibrium studies. Because no line differences in the potencies of these drugs to inhibit [35S]TBPS binding were found using equilibrium conditions, these results indicate that the association rates of barbiturates and GABA may be different between these lines. These findings are consistent with neurochemical studies indicating differences in the benzodiazepine/GABA receptor-chloride channel complex in these selected lines and may explain their differential sensitivities to certain agents acting through this supramolecular complex.

Animals↗
PubMed1991

Effects of various music conditions on multiple dimensions of behavior of emotionally disturbed adolescents.

The effects of music on the behaviors of 5 to 8 emotionally disturbed adolescents were investigated. Six behavioral categories of aggressive motor, aggressive verbal, disruptive motor, disruptive verbal, nondisruptive/off task, and on task, were monitored in class daily for 40 min. for 12 wk. to assess whether three conditions of "sedative," "stimulating," and "no music" influenced the frequency of these behaviors. Analysis indicated no significant differences in frequencies of any of the six behavior categories among music conditions.

Adolescent↗