• The Korean Journal of Pharmacology
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• v.31 no.1 s.57
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• pp.123-133
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• 1995

A number of tricyclic antidepressants appear to have inhibitory action on calmodulin. Although amitriptyline, imipramine and doxepine have been shown to inhibit calcium uptake, oxidative phosphorylation and ATPase activities, effects of amitriptyline, imipramine and doxepine on functional responses of human neutrophils have not been elucidated. In this study, effects amitriptyline, imipramine and doxepine on superoxide and hydrogen peroxide generation, myeloperoxidase release, leukocriene B4 formation and intracellular calcium level were investigated. Superoxide and hydrogen peroxide production in heat aggregated IgG-activated neutrophils were inhibited by amitriptyline, imipramine and doxepine. EDTA, EGTA, verapamil and bepredil inhibited heat aggregated IgG-induced superoxide production. Chlorpromazine, trifluoperazine, staurosporine and H-7 also inhibited it. PMA-induced superoxide production was inhibited by amitriptyline, imipramine, doxepine, chlorpromazine and H-7. Amitriptyline, imipramine, chlorpromazine and trifluoperazine inhibited the myeloperoxidase release by heat aggregated IgG. Productions of $LTB_4$, and 5-HETE in heat aggregated IgG-activated neutrophils were inhibited by amitriptyline, imipramine and doxepine. In neutrophils, elevation of intracellular calcium induced by heat aggregated IgG was inhibited by amitriptyline, imipramine, doxepine, chlorpromazine and EGTA, while verapamil slightly inhibited increase of intracellular calcium and H-7 did not inhibit it. These results suggest that the inhibitory effect of amitriptyline, imipramine and doxepine on respiratory burst, myeloperoxidase release and LTB4 production in heat aggregated IgG-activated neutrophils appears to be ascribed to the inhibition of calcium mobilization, calmodulin and protein kinase C.

• The Korean Journal of Pharmacology
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• v.26 no.1
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• pp.55-66
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• 1990

In both resting and opsonized zymosan activated neutrophils, ATP stimulated superoxide generation, whereas adenosine inhibited it slightly. The superoxide generation in activated neutrophils to ATP was greater than that of resting neutrophils. In $Ca^{++}$ free medium, inhibitory effect of adenosine on superoxide generation was detectable, whereas ATP did not have any effect. The stimulatory effect of ATP on superoxide generation was inhibited by adenosine in a dose dependent manner. Neither ATP nor adenosine had any effect on NADPH oxidase acitivity. Effects of ATP or adenosine on superoxide generation were more prominent than that by other triphosphate nucleotides or nucleosides. ATP and ADP further stimulated $Ca^{++}$ uptake and increased cytosolic free $Ca^{++}$ level in neutrophils activated by opsonized zymosan, but adenosine inhibited a $Ca^{++}$ mobilization. Verapamil effectively and tetrodotoxin slightly inhibited an increase of cytosolic free $Ca^{++}$ level induced by ATP. Inhibitory effect of either verapamil or tetrodotoxin on superoxide generation in the ATP plus opsonized zymosan-activated neutrophils was greater than in the cells activated by opsonized zymosan alone. Tetraethylammonium chloride had no apparent effect on superoxide generation. CCCP, 2,4-dinitrophenol, diphenylhydantoin and procaine all inhibited superoxide generation in neutrophils activated by opsonized zymosan. Among these, CCCP only inhibited a stimulatory effect of ATP. ATP further stimulated a loss of sulfhydryl groups in activated neutrophils, whereas adenosine had no effect on it. These results suggest that functional responses of neutrophils may be regulated at least partly by purines. ATP and adenosine may further after functional responses of activated neutrophils through their effect on $Ca^{++}$ uptake, membrane phosphorylation and oxidation of soluble sulfhydryl groups.

• The Korean Journal of Pharmacology
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• v.28 no.1
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• pp.91-102
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• 1992

In $Ca^{++}$ containing media, arachidonic acid markedly stimulated superoxide and $H_2O_2$ generation and activated NADPH oxidase. In $Ca^{++}$ free media, stimulatory action of arachidonic acid on NADPH oxidase was not detected. Arachidonic acid-stimulated respiratory burst was inhibited by EGTA, TMB-8, verapamil, diltiazem, nifedipine, dibucaine, lidocaine, CCCP, 2,4-dinitrophenol, sodium arsenate, chlorpromazine, theophylline, $HgCl_2$, PCMB and PCMBSA but not affected by tetrodotoxin, tetraethylammonium chloride and procaine. EGTA almost completely inhibited release of ${\beta}-glucuronidase$ by arachidonic acid and verapamil, CCCP and theophylline slightly inhibited it, whereas dibucaine did not show any significant effect. Arachidonic acid induced $Ca^{++}$ release from intact neutrophils and it was decreased by TMB-8. Arachidonic acid-induced elevation of intracellular free $Ca^{++}$ level was inhibited by EGTA and CCCP and slightly inhibited by TMB-8. Amount of intracellular free $Ca^{++}$ increased by either arachidonic acid plus verapamil or arachidonic acid plus dibucaine was greater than that by arachidonic acid alone. These results suggest that various changes of biochemical events may be implicated in the functional expression in neutrophils activated by arachidonic acid. Arachidonic acid appears to elevate cytosolic free $Ca^{++}$ level by stimulating $Ca^{++}$ release from intracellular $Ca^{++}$ storage sites. During activation of neutrophils, $Ca^{++}$ influx and efflux may be accomplished, simultaneously.

• Tuberculosis and Respiratory Diseases
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• v.40 no.1
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• pp.16-22
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• 1993

Background: The Microbicidal and cytotoxic activities of neutrophils are to a large extent dependent on a burst of oxidative metabolism which generates superoxide anion, hydrogen peroxide, and other reactive products of oxygen. The respiratory burst of PMN is initiated by intracellular calcium mobilization that follows immune or particular stimulation and is very sensitive to modulation by c-AMP or adenosine. Despite its antagonism against adenosine, earlier study has demonstrated potent theophylline inhibition of the PMN respiratory burst at variable ranges of blood concentrations of theophylline in the healthy normal volunteers and in the septic animals pretreated or early post-treated with aminophylline (AMPH) or pentoxifylline. However it is unclear whether theophylline inhibits the superoxide generation or not in the established human sepsis caused by acute pneumonia, as taking into consideration of the fact that full activation of neutrophils have occurred within minutes after the septic insult in the animal experiments. Methods: We measured the $O_2$ generation of peripheral arterial neutrophils obtained from 11 human septic subjects caused by acute pneumonia before and 1 hour after completion of continuous AMPH infusion. Patients were identified and studied within 48 hour of admission. All subjects were administered an intravenous loading and maintenance dose of AMPH. The generation of $O_2$ was measured at a discrete time point (60 min) by the reduction of ferricytochrome c.PMA (10 ${\mu}g/ml$) was used as a stimulating agent. PMNs were isolated at a concentration of $2{\times}10^6$ cells/ml. The arterial oxygen tension, blood pressure and heart rates were also checked to evaluate the systemic effects of AMPH in the acute pneumonia. Results: The mean serum concentration of AMPH at 60 minutes was $8.8{\pm}0.6{\mu}g/ml$. Sixty minutes after AMPH infusion the generatition of $O_2$ was decreased from $0.076{\pm}0.034$ to $0.013{\pm}0.004$(OD) (p<0.05) and from $0.177{\pm}0.044$ to $0.095{\pm}0.042$(OD) (p<0.01) in the resting and stimulated PMNs respectively. $PaO_2$ was not changed after AMPH infusion. Conclusion: AMPH may compromise host defense by significant inhibition of neutrophil release of superoxide anion and it had no effect on improving $PaO_2$ in the acute pneumonia.

• The Korean Journal of Pharmacology
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• v.29 no.1
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• pp.107-120
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• 1993

Particulate or soluble stimuli appear to stimulate phagocytic cell's response by the change of $Ca^{2+}$ mobilization and by the activation of protein kinase C. In contrast, it is reported that activation of protein kinase C could attenuate agonist-stimulated elevation of $Ca^{2+}i$ in neutrophils. PAF elicited an increase of $Ca^{2+}i$ in peritoneal macrophages in a dose dependent fashion and $Ca^{2+}$ extrusion was accompanied. PAF-induced elevation of $Ca^{2+}i$ was not affected by TMB-8, verapamil and TTX. TEA stimulated PAF-induced mobilization of $Ca^{2+}i$ and delayed lowering of $Ca^{2+}i$. Five mM EGTA almost completely inhibited PAF-induced mobilization of $Ca^{2+}i$. After the addition of PAF, membrane permeability was markedly increased up to 5 min and then slowly increased. PAF-induced LDH release was slightly decreased by EGTA plus TMB-8. PAF-stimulated superoxide generation was inhibited by EGTA, TMB-8 and verapamil but not affected by TTX and TEA. PAF-induced elevation of $Ca^{2+}i$, increased membrane permeability and superoxide generation were inhibited by IQSP, chlorpromazine and propranolol. PAF-induced LDH release was significantly inhibited by chlorpromazine and minimally decreased by propranolol. After the pretreatment with PMA, the stimulatory effect of PAF on the elevation of $Ca^{2+}i$ and LDH release in macrophages was significantly decreased. These results suggest that PAF may exert the stimulatory action on peritoneal macrophages of mouse by the elevation of $Ca^{2+}i$ and by the activation of protein kinase C. Preactivation of protein kinase C appears to attenuate the stimulatory action of PAF on macrophage response.