Coexistence of energy-dependent and non-dependent processes in the histamine release mechanism of compound 48-80 and sinomenine: experiments on skin from various animal species

Histamine release from the isolated guinea-pig heart by compound 48/80

Histamine release was observed in isolated guinea-pig heart perfused by the constant flow method, after bolus injection of 50-200 micrograms of compound 48/80. Practically all the histamine is released within the first 3 min after 48/80. This effect is inhibited by the addition of sodium cyanide (300 microM) to a glucose-free perfusion fluid and also by the removal of calcium of the medium in presence or absence of EDTA (100 microM). This dependence on metabolism and calcium is highly suggestive of a non-cytotoxic action of 48/80 on the mast cells of guinea-pig heart.

Possible involvement of cyclic AMP in inflammation induced by a surfactant

Alkyldimethylbenzylammonium chloride (alkyl-DBAC), a cationic surfactant, produces acute exudative inflammation accompanied by an enhancement of energy metabolism. The mechanism of metabolic changes, consequently the cyclic AMP level and the effects of certain drugs were determined in the gastrocnemius muscles of rats in which acute exudative inflammation had been induced by intramuscular injections of alkyl-DBAC. A transient increase in the cyclic AMP level was noted at 15 to 30 minutes after the injection of alkyl-DBAC, and this elevation was antagonized by chlorpromazine, diphenhydramine, promethazine, aspirin and indomethacin. The time course of increasing tendency in the cyclic AMP level after the injection of histamine closely paralleled that of alkyl-DBAC. These results suggest that cyclic AMP may be involved in the metabolic changes with inflammation induced by alkyl-DBAC.

Effects of ID-540 on averaged photopalpebral reflex in man

Effects of ID-540, a recently introduced benzodiazepine derivative, on the averaged photopalpebral reflex (PPR), subjective symptoms and serum levels of ID-540 and its principal metabolite, N-desmethyl-ID-540 following an oral dose of 0.5 mg were investigated in 4 healthy male Japanese students in their early twenties. Both the latencies of PPR, P1 and P2 latency, showed a prolongation and maximum level at 2-2.5 hours after administration and tended to decline thereafter to control levels. The serum concentration of ID-540 showed a peak level at 2 hours after dosing, then showed a decline at 4 hours. The N-desmethyl-ID-540 exhibited a slow, gradual rise in the serum over the first 4 hours and there was a tendency toward a continued rise even at 24 hours. These parameters were of striking resemblance in the time-course of changes after oral dosing. Thus the PPR test may be a useful means of determining the clinical effects of anxiolytic agents. ID-540 appears to be an agent with remarkable anxiolytic effects.

Histamine release by Western red cedar (Thuja plicata) from lung tissue in vitro

Evans, Elizabeth and Nicholls, P. J. (1974).British Journal of Industrial Medicine,31, 28-30. Histamine release by Western red cedar(Thuja plicata)from lung tissue in vitro. Various respiratory symptoms have previously been observed in workers exposed to dust from Western red cedar (Thuja plicata). Although an allergic basis for these effects has been proposed, the possibility that the dust may contain a pharmacologically active agent was investigated. Aqueous extracts of two samples of red cedar released significant amounts of histamine from pig and human lung in vitro. For one of these samples, using pig lung, a dose-response relation was found over a narrow range of concentrations. These dusts possessed the same order of histamine-releasing activity as a sample of cotton dust. Potassium cyanide reduced the release of histamine caused by low concentrations of Western red cedar. Similar effects of cyanide on the histamine-releasing activity of cotton dust and compound 48/80 were observed. It is possible that release of histamine in the lungs and upper respiratory tract occurs on inhalation of dust from Western red cedar and this may be a contributory factor to the development of respiratory symptoms in workers exposed to the dust of this wood.

Histamine-releasing activity and bronchoconstricting effects of sisal

Nicholls, P. J., Evans, E., Valić, F., and Žuškin, E. (1973).British Journal of Industrial Medicine,30, 142-145. Histamine-releasing activity and bronchoconstricting effects of sisal. Extracts of dry and oiled sisal released histamine from pig and human but not from rat lung tissue. A suspension in Tyrode solution of the oil used for softening the sisal fibres had a pH of 8·1 and also released histamine from pig and human lung. The releasing activity was abolished when the pH of this suspension was adjusted to pH 7·4. As all the sisal extracts were adjusted to pH 7·4 for incubation with lung tissue, the histamine-releasing activity of sisal in vitro is unrelated to the presence of the oil. Significant (P < 0·01) mean reductions over the work shift of ventilatory capacity (PEF and FEV_1·0) were recorded in all the workers exposed to airborne sisal dust. These reductions were greater in combers than in drawers and spinners. Sisal collected from combing machines possessed more histamine-releasing activity than material from drawing and spinning machines. These results indicate that histamine release by sisal may be the cause of acute ventilatory capacity changes in sisal exposure.

Mechanisms of histamine release by compound 48-80

1. Rat and guinea-pig lung tissues were incubated for 20 min at 37 degrees C in Krebs-Ringer phosphate buffer at pH 7.4, or in Tyrode-Tris buffer at pH 8.2, and the release of histamine produced by adding different concentrations of compound 48/80 to the incubation medium was determined.2. At pH 7.4, increasing concentrations of 48/80 increased the release of histamine from the rat lung, with a tendency towards a maximum. No release of histamine from guinea-pig lung was observed at this pH. At pH 8.2, histamine release occurred both from rat and guinea-pig lung, and was proportional to the logarithm of the concentration of compound 48/80.3. Histamine release from rat lung by 20 mug/ml. of 48/80 decreased when the pH was raised from 7.4 to 8.2; but the release caused by 1 mg/ml. of 48/80 increased both in rat and guinea-pig lung as the pH was raised.4. 2-4-Dinitrophenol (DNP) inhibited the release of histamine from rat lung by a concentration of 20 mug/ml. of 48/80; the inhibition was prevented by glucose. DNP did not affect histamine release from rat or guinea-pig lung by a concentration of 1 mg/ml. of 48/80 and enhanced the release when the pH was raised from 7.4 to 8.2.5. 1 mg/ml. of 48/80 did not inhibit the enhanced oxygen consumption produced by DNP in the isolated rat diaphragm.6. Iodoacetic acid (IAA) or a Ca/Mg-free medium inhibited the release of histamine by 20 mug/ml. of 48/80 from rat lung but not the release produced by 1 mg/ml. in either rat or guinea-pig lung.7. The degranulation of rat mesentery mast cells caused by 20 mug/ml. of compound 48/80 was inhibited by DNP. The degranulation evoked by 1 mg/ml. of 48/80 was also sensitive to this inhibitor; in this instance, however, the metachromatic staining reaction of the mesentery mast cells was greatly diminished.8. It is concluded that two processes of histamine release by compound 48/80 occur in rat lung. One, dependent on cell metabolism, involves, mast cell granule secretion. The other, independent of cell metabolism, seems to consist of a simple exchange reaction between histamine and compound 48/80, and this is the only one occurring in guinea-pig lung.