Different effects of local anesthetics on calcium influx into rat mast cells

Lidocaine, W49091, procaine and benzocaine inhibited mast cell secretion induced by concanavalin A and A23187. They inhibited Ca influx stimulated by concanavalin A, suggesting that they inactivate Ca channel of mast cells. Lidocaine and procaine inhibited Ca influx stimulated by A23187, but W49091 and benzocaine did not.     

The effects of nonidet P40 on the function of rat peritoneal mast cells in vitro

1 Treatment of purified rat peritoneal mast cells at 37 degrees C with concentrations of the non-ionic detergent nonidet P40 (NP40) up to 0.005% (v/v) failed to reduce their viability. 2 There was a marked reduction in the histamine releasing capacity of NP40-treated mast cells upon challenge with a variety of selective (adrenocorticotrophic hormone 1-24 (Synacthen), rabbit anti-rat IgE antiserum, adenosine triphosphate (ATP) and the calcium ionophore, A 23187) and non-selective (rabbit anti-rat mast cell antiserum plus complement) histamine liberators. 3 Nonidet P40 (0.005%) was found to reduce the activity of a mast cell membrane 'ecto-enzyme', calcium-activated ATPase, by about 45% when presented at the time of its assay.     

Dual actions of adenosine on rat peritoneal mast cells

Summary The effects of adenosine and its analogues on cAMP-responses and histamine release of rat peritoneal mast cells were investigated. The adenosine analogue 5-N-ethylcarboxamidoadenosine (NECA') activates the adenylate cyclase of the mast cell membranes and elevates the cAMP-levels of the intact mast cells. Both effects are antagonized by methylxanthines, suggesting that they are mediated via an A₂ adenosine receptor. Adenosine and its analogues enhance the release of histamine from these cells, when the release is stimulated either by the calcium ionophore A 23187 or by concanavalin A. However, this effect is not antagonized by theophylline or 8-phenyltheophylline. In contrast, it is antagonized by the adenosine uptake blockers S-(p-nitrobenzyl)-6-thioinosine (NBTI) and S-(p-nitrobenzyl)-6-thioguanosine (NBTG). It is concluded that adenosine has two different effects on mast cells: it activates adenylate cyclase via an A₂ adenosine receptor, and it enhances histamine release via an action at an intracellular site.Abbreviations NECA 5-N-ethylcarboxamidoadenosine - NBTI S-(p-nitrobenzyl)-6-thioinosine - NBTG S-(p-nitrobenzyl)-6-thioguanosine - PIA N⁶-phenylisopropyladenosine - Con A concanavalin A Send offprint requests to M. J. Lohse at the above address     

Histamine release from isolated rat mast cells induced by opiates: effect of sterical configuration and calcium

The stereospecificity of the action of opiates on rat mast cells was investigated by means of the l- and d-isomers levorphanol and dextrorphan. The dose-response curves for histamine release induced by the 2 drugs were of a similar shape with a maximum at 2 X 10(-3) M and a pronounced minimum at 5 X 10(-3) M. At concentrations below 5 X 10(-3) M the effect of both drugs resembled that of morphine, i.e. the release occurred rapidly and inhibition was observed with naloxone, codeine, and antimycin A. Levorphanol, dextrorphan, and the antagonist levallorphan at concentrations above 5 X 10(-3) M seemed to be toxic to mast cells. The uptake of 45Ca in connection with histamine release induced by pethidine, levorphanol, and dextrorphan was lower than that of control cells, whereas the uptake induced by morphine did not differ from that of controls. The inhibition of compound 48/80-induced histamine release by morphine was paralleled by a reduced 45Ca uptake. The time course for the inhibitory effect of preincubation with morphine was similar for the histamine released induced by morphine and by compound 48/80. Washing of the cells after preincubation with morphine was without effect on the inhibition of morphine-induced histamine release, whereas the inhibition of compound 48/80 was reduced. The present observation with morphine and compound 48/80 support our previous impression of similarities in their mode of action, but a mechanism implying an interference by morphine with the disposition of calcium could also account for the findings. The observed antagonism between morphine and calcium resembles that of opiate receptors, but histamine release induced by opiates does not involve stereospecific opiate receptors.     

Comparative effects of oxatomide on the release of histamine from rat peritoneal mast cells

Oxatomide inhibits the release of histamine from rat peritoneal mast cells in vitro induced by C 48/80, antigen, anti-IgE and ionophore A 23 187, without effect on non-specific release by n-decylamine. Its effect is concentration- and pH-dependent and decreases with increasing extracellular Ca2+-concentrations. Prolonged incubation does not enhance the inhibition, which is lost after one single wash-out. Aminophylline and isoproterenol are not potentiated by oxatomide. The present study points to an effect of oxatomide on a Ca2+-dependent process at the level of cell membrane common to antigen, C 48/80 and ionophore A 23 187.     

Vaginal bacterial flora activates rat peritoneal mast cells

Sixteen strains of physiological and pathological vaginal bacteria were tested for their ability to secrete histamine from rat peritoneal mast cells in vitro. We noticed that Mycoplasma hominis-induced histamine release was very high (up to 53.6%). The stimulation of rat mast cells with Staphylococccus cohnii, Staphylococcus coagulase(-) (two strains), Ureaplasma urealyticum, Peptostreptococcus spp., Bacteroides capillosus, Staphylococcus aureus and Streptococcus agalactiae resulted in lower but significant histamine secretion (11.2%-17.5%). Other bacteria strains (Staphylococcus epidermidids, Enterococcus faecalis, Escherichia coli, Actinomyces naeslundii (two strains) and Lactobacillus fermentum (two strains) caused very low (4.2% - 8.8%) histamine release.     

Histidine transport by isolated rat peritoneal mast cells

Kinetic constants for the transport of [³H]histidine into isolated rat peritoneal mast cells were determined. The value of K_m for histidine transport was 44.0 μM; the value of V_max under the same conditions was 18.9 pinoles · min^? · (10⁶ cells)^?1. These parameters did not change in value after the addition of exogenous histamine. The uptake of histidine and its decarboxylation to histamine were relatively rapid processes compared to the transfer of the newly formed histamine into mast cell granules, so that nascent histaramine appeared transiently in the cytoplasm. Amino-acid competition experiments support the assignment of L system transport for the bulk of histidine uptake by mast cells. Metabolic inhibitors that deplete cellular ATP did not inhibit the uptake process.     

Synergistic effects of calcium-mobilizing agents and adenosine on histamine release from rat peritoneal mast cells

1. Adenosine and its metabolically stable analogue N-ethyl-carboxamidoadenosine (NECA) enhance histamine release from rat peritoneal mast cells when these are stimulated by calcium-mobilizing agents. NECA and adenosine shift the concentration-response curve of the calcium ionophore A23187 to lower concentrations. 2. The potencies of NECA or adenosine in enhancing A23187-induced histamine release are dependent on the level of stimulated release in the absence of adenosine analogues. At high levels of release their potencies are up to 20 times higher than at low levels. Consequently, averaged concentration-response curves of adenosine and NECA for enhancing histamine release are shallow. 3. The adenosine transport blocker S-(p-nitrobenzyl)-6-thioinosine (NBTI) has no effect by itself at low levels of stimulated histamine release, but abolishes the enhancing effect of adenosine. At high levels of release, however, NBTI alone enhances the release of histamine. 4. It is concluded that adenosine and calcium reciprocally enhance the sensitivity of the secretory processes to the effects of the other agent. The levels of intracellular adenosine obtained by trapping adenosine inside stimulated mast cells are sufficient to enhance histamine release substantially, suggesting that this effect may play a physiological and pathophysiological role.     

Characterization of protease-activated receptors in rat peritoneal mast cells

Activation of protease-activated receptor (PAR)-1 or PAR-2 elicits inflammation most probably via mast cell degranulation in vivo. The present study aimed at characterizing PARs in rat peritoneal mast cells (PMC). Messenger RNA for PAR-1, but not for PAR-2, was detected in PMC. Thrombin, the PAR-1 agonist SFLLR-NH2 or the PAR-2 agonist SLIGRL-NH2 failed to induce histamine release from PMC. Surprisingly, the PAR-2-inactive control peptide LSIGRL-NH2 triggered histamine release from PMC. Thus, PAR-1, but not PAR-2, are expressed in PMC, whereas neither PAR-1 nor PAR-2 are considered to be involved in degranulation of PMC. LSIGRL-NH2 does not appear to be appropriate as a control peptide for PAR-2 in inflammation studies.     

Inhibition of allergic and non-allergic histamine secretion from rat peritoneal mast cells by calcium antagonists.

Bepridil, TMB-8 (8-(diethylamino)octyl 3,4,5-trimethoxybenzoate hydrochloride), diltiazem, verapamil and nifedipine exerted concentration-dependent inhibition of antigen and calcium ionophore A23187-induced histamine release from rat peritoneal mast cells. The inhibitory effects of verapamil and bepridil against calcium ionophore A23187-induced histamine secretion were antagonized by increased Ca2+ concentrations in the extracellular medium. These observations suggest that both agents act by interfering with the influx of Ca2+ into the mast cells. The inhibitory activities of five different Ca2+ channel blockers on allergic and non-allergic histamine secretion from rat peritoneal mast cells varied considerably depending upon the nature of the secretagogue as well as concentration and type of Ca2+-antagonist examined.     

Desensitization of rat peritoneal mast cells to substance P

Rat peritoneal mast cells were pretreated for 10 min at 37 degrees C with either substance P (SP, 3 or 6 microM) or compound 48/80 (37.5, 50 or 75 ng/ml). The effect of this pretreatment on the subsequent responsiveness of the cells to SP was studied. Both SP and compound 48/80 pretreatment of rat peritoneal mast cells inhibited the subsequent response of the cells to SP. The degree of inhibition produced by either SP or compound 48/80 was dependent on the concentration used to pretreat the cells. Inhibition of the response of the cells to SP was observed whether or not the pretreating agent was removed or remained in contact with the cells during the subsequent stimulation with SP. It is concluded that compound 48/80 and SP desensitize the cells to subsequent stimulation by SP and possible mechanisms for this are discussed.     

Effects of chymotrypsin and trypsin on rat peritoneal mast cells.

Alpha-chymotrypsin was demonstrated to release histamine from rat peritoneal mast cells. Release of histamine was shown by electron microscopy not to be cytotoxic. Release was temperature dependent, required Ca²⁺ and cell ATP for optimal effect, and involved the direct action of α-chymotrypsin on the mast cells. Trypsin was far less active in releasing histamine, but exposure of the cells to trypsin inhibited the subsequent release of histamine by chymotrypsin. The relationship between the action of exogenous α-chymotrypsin and an endogenous “activatable” esterase could not be established from this set of experiments because the release of histamine by polymyxin B was only slightly inhibitable by the esterase inhibitor, dusopropylfluorophosphate, and, therefore, did not apparently require the participation of the endogenous esterase.     

Differential effects of anti-allergic compounds on peritoneal mast cells of the rat, mouse and hamster

The effects of various inhibitors and anti-allergic drugs on histamine secretion from peritoneal mast cells of the rat, mouse and hamster have been compared. Phosphodiesterase inhibitors, cAMP analogues and beta-adrenoceptor agonists variously blocked release of the amine from all three cell types. The mouse cells were rather less sensitive to the former agents than those of the rat and hamster. Disodium cromoglycate inhibited histamine secretion from rat peritoneal mast cells, was less active against the hamster cells and completely ineffective against those of the mouse. Other chromones showed varied patterns of differential reactivity but phloretin and the flavonoid quercetin were essentially equiactive against all three cell types. The tetrazoles AH 9679 and doxantrazole prevented histamine release in each case but were significantly less active against the mouse cells. These results further emphasize the functional heterogeneity of mast cells from different sources.     

Peptides and histamine release from rat peritoneal mast cells

Various vasoactive peptides were compared for their histamine releasing effects on rat mast cells. Neurotensin, substance P (SP), and kallidin were the most active natural peptides, followed by bradykinin; neurokinin A and B, bombesin, angiotensin and tuftsin were practically inactive. Several kinins and tachykinin-related peptides were tested in an attempt to characterize the receptors mediating histamine liberation. The order of potency of the kinins was the following: kallidin greater than [Tyr(Me)8]bradykinin = bradykinin greater than [desArg10]kallidin greater than desArg9-bradykinin, the same as that found in smooth muscle possessing receptors of the B2 type. Tachykinin-related peptides were potent stimulants and followed the order: [D-Tryp7,9,10]SP-(1-11) greater than [D-Pro2,D-Tryp7,9,10]SP-(1-11) greater than SP-(1-11) greater than SP-(1-9) greater than [D-Pro4,D-Tryp7,9,Leu11]SP-(4-11) greater than SP-(1-7) greater than SP-(4-11) greater than neurokinin A = neurokinin B, indicating that: (a) undecapeptide antagonists of SP behave as superagonists; (b) both N- and C-terminal portions of SP-(1-11) are essential for activity; and (c) receptors for the tachykinins mediating histamine release appear to be of the SP-P type.     

Neurotensin effect on dopamine release and calcium transport in rat striatum: interactions with diphenylalkylamine calcium antagonists

Summary The release of dopamine was investigated in rat striatal slices exposed in vitro to neurotensin. This peptide increased basal and K⁺-evoked dopamine release. Moreover neurotensin antagonized the flunarizine-induced inhibition of K⁺-stimulated dopamine release. The K⁺-evoked ⁴⁵Ca²⁺ accumulation was also inhibited by flunarizine. This effect was antagonized by neurotensin. The results suggest that dopamine release in rat striatum is regulated by different molecular events also of peptidergic nature having as possible mechanism of action an influence on calcium ion movements.     

The effect of platelet-activating factor on histamine release from rat peritoneal mast cells.

The effect of platelet-activating factor (PAF) on histamine release from peritoneal mast cells of adult and young male rats was investigated. PAF alone tended to release histamine from the mast cells of adult and young rats, although very slightly. On the other hand, PAF significantly inhibited the histamine release induced by the Ca2+ ionophore A23187 in mast cells obtained from rats of either age group, but not that by compound 48/80. Such inhibition was not seen with lyso-PAF. CV-3988, a PAF antagonist, antagonized the inhibitory effect of PAF on the A23187-induced histamine release in mast cells from adult and young rats. These results suggest that PAF does not have a strong histamine-liberating action on mast cells, and that PAF inhibits the calcium influx into mast cells through the activation of PAF receptors.     

Differential inhibitory effects of the arachidonic acid analog ETYA on rat mast cell exocytosis evoked by secretagogues utilizing cellular or extracellular calcium

ETYA (5,8,11,14-eicosatetraynoic acid; 50-100 microM), which inhibits both cyclo-oxygenase and lipoxidase, inhibited histamine release evoked by secretagogues dependent on extracellular calcium (antigen, dextran, and concanavalin A) but failed to inhibit secretion elicited by secretagogues capable of mobilizing calcium from intracellular sites (48/80, polymyxin B, protamine sulfate and poly-L-lysine). Responses to these latter secretagogues were inhibited only by higher concentrations of ETYA (100-200 microM) that were cytotoxic. Secretion evoked by the calcium ionophore A23187 (0.1 microgram/ml) was inhibited at much lower concentrations of ETYA (1-10 microM) but this inhibition could not be overcome by increasing the concentration of calcium. Responses to higher concentrations of ionophore were not inhibited by ETYA except in amounts affecting cell viability. Like ETYA, each of several fatty acids, including arachidonic acid, were inhibitory towards histamine release evoked by A23187 or 48/80. The results indicate that EYTA acts at some early stage of stimulus-secretion coupling rather than on the final, common, calcium-activated steps of exocytosis. Moreover, this action may be unrelated to inhibition of lipoxidase or cyclooxygenase.     

Dextran-induced release of serotonin from isolated rat peritoneal mast cells

Dextran (9 mg/ml incubate) was found to induce a serotonin (5-HT) release from isolated rat peritoneal mast cells of about 10% within an incubation period of 5 min. at 37 degrees. The extent of release was not increased by using higher concentrations of dextran or by increasing the incubation period from 5 to 20 min. The dextran-induced release of 5-HT was increased to 50-60% when the mast cells were preincubated with phosphatidylserine (PS) in doses of 2.6-4.3 microgram/ml incubate. Higher concentrations of PS alone induced a rapid 5-HT release of approximately 50-60%. The 5-HT release process studied was found to possess both similarities and dissimilarities with the previously described dextran-induced release process of histamine, also studied in isolated rat peritoneal mast cells. The results supported previous indirect evidence of a 5-HT release from mast cells in the early phase of the dextran-induced anaphylactoid reaction in the rat.     

Effect of cromoglycate on anaphylactic histamine release from rat peritoneal mast cells

Cromoglycate (1-30 muM) produced a concentration-dependent inhibition of anaphylactic histamine release from actively sensitized rat peritoneal mast cells but at lower concentrations (0.01-0.1 muM) occasionally produced a concentration-dependent enhancement of histamine release.     

Proteins in the plasma membranes of rat peritoneal mast cells

Plasma membranes of peritoneal mast cells from rats specifically bred for resistance to the dextran anaphylactoid reaction contain a polypeptide of molecular weight about 74,000 daltons which is deficient in those from rats which react to dextran. This polypeptide may modify the dextran receptor on the mast cell membranes of resistant rats so that histamine release does not take place when these cells are challenged with clinical dextran.