Histamine release by adrenaline and D-tubocurarine in the human subject

Gantacurium and CW002 do not potentiate muscarinic receptor-mediated airway smooth muscle constriction in guinea pigs

BACKGROUND

Neuromuscular blocking agents are an integral component of general anesthesia. In addition to their intended pharmacologic target on skeletal muscle nicotinic receptors, undesirable airway effects (i.e., bronchoconstriction) can result from neuromuscular blocking agents' affinity for airway muscarinic receptors. We questioned whether two new members of a bisquaternary nondepolarizing muscle relaxant family, gantacurium and CW002, demonstrated detrimental effects of airway muscarinic receptors using an in vivo model in guinea pig airways.

METHODS

Urethane-anesthetized male guinea pigs were ventilated through a tracheostomy with continuous digital recordings of pulmonary inflation pressure and heart rate. The dose for 95% twitch suppression for gantacurium, CW002, cisatracurium, and rapacuronium was defined in the guinea pig. Transient and reproducible changes in pulmonary inflation pressure and heart rate were recorded after vagal nerve stimulation or intravenous injection of acetylcholine before and after pretreatment with cumulatively increasing concentrations of gantacurium, CW002, cisatracurium or a single concentration of rapacuronium.

RESULTS

The doses for 95% twitch suppression for gantacurium, CW002, cisatracurium, and rapacuronium were 0.064 +/- 0.006, 0.012 +/- 0.0006, 0.10 +/- 0.003, and 0.31 +/- 0.05 mg/kg, respectively. Gantacurium, CW002, and cisatracurium were without effects on baseline pulmonary inflation pressures and were devoid of significant interactions with M2 and M3 muscarinic receptors in vivo.

CONCLUSION

These findings suggest that gantacurium and CW002 are devoid of significant effects at airway muscarinic receptors particularly M3 receptors on bronchial smooth musculature at doses several fold higher than those required for functional muscle paralysis.

Modulation of the spontaneous histamine release by adrenergic and cholinergic drugs

Experiments have been reported on the possible modulation of the spontaneous histamine release by adrenergic and cholinergic drugs. Adrenergic drugs increase the spontaneous histamine release in vivo, and in neoplastic mast cells, in vitro. The mechanism of histamine release appears to be dependent upon the activation of alpha-adrenoceptors. Cholinergic drugs activate the release of histamine in many secretory processes in vivo; in vitro, acetylcholine is one of the most powerful histamine releasers in isolated purified rat mast cells. The release of histamine evoked by acetylcholine in rat mast cells is a calcium-requiring, temperature-dependent exocytosis. The physiological relationship of the sympathetic, parasympathetic and histamine-containing cells are discussed.

Experimental and clinical evaluation of neuromuscular blocking agents

Neuromuscular blocking agents can be evaluated in anesthetized cats, dogs, or rhesus monkeys using dose-response relationships to assess the degree of separation between neuromuscular blocking activity and effects on cardiovascular and autonomic systems. Histamine release can be studied in anesthetized dogs by establishing whether any induced hypotension is reduced by pretreatment with H1 and H2 receptor antagonists. In anesthetized cats, the role of the liver in metabolism is investigated after administration of the drug by the hepatic portal vein and determining whether this "first pass" effect through the liver reduces potency. The involvement of the kidneys in the elimination of the drug can be assessed by ascertaining whether or not the potency and duration of action are enhanced after bilateral renal ligation. In anesthetized man, the simultaneous measurement of the tetanic (50 Hz) and single twitch contractions of the adductor pollicis muscle of the hand has proved a valuable technique for the quantitative assessment of skeletal muscle relaxants. Furthermore, the tetanic response overcomes the relative insensitivity of the single twitch, and tetanic fade provides a measure of the effects of these drugs at presynaptic sites. Cumulative effects may be evident as a prolonged recovery after repeated dosage or after an infusion. The effectiveness of neostigmine as an antagonist should be investigated both from partial and complete block, and recovery of respiration should be compared with that of peripheral neuromuscular blockade.

Anaphylaxis to muscle relaxant drugs: cross-reactivity and molecular basis of binding of IgE antibodies detected by radioimmunoassay

IgE antibodies that bind the muscle relaxant alcuronium were found in sera from six patients who experienced anaphylactic-like reactions following administration of the drug during induction of anaesthesia. Drug-specific antibodies were detected by radioimmunoassay employing a covalently coupled alcuronium-Sepharose complex and 125I-labelled anti-human IgE. Quantitative inhibition studies undertaken with the sera revealed specificity differences between IgE antibodies from different patients. One serum reacted with alcuronium but not with five other muscle relaxants, decamethonium, gallamine, pancuronium, succinylcholine and tubocurarine. IgE antibodies in the other sera cross-reacted with the muscle relaxants, other quaternary ammonium compounds and some pharmacologically unrelated drugs including promethazine, morphine, neostigmine and pentolineum. The inhibition experiments revealed that the alcuronium-IgE reaction could be prevented or diminished by structures containing a substituted ammonium ion. As these ions occur widely in man's environment in drugs, cosmetics, disinfectants, foods and industrial materials, it seems possible that sensitization of patients may occur without previous exposure to muscle relaxants.

Substituted ammonium ions as allergenic determinants in drug allergy

Serious, and occasionally fatal, anaphylactic-like (anaphylactoid) reactions may occur when a patient is exposed to a drug for the first time. Apart from the penicillins, nothing is known of the nature of antigenic or sensitizing drug determinants and, as yet, there is no evidence for the involvement of IgE antibodies in most drug reactions. Muscle relaxants such as alcuronium have been implicated in many life-threatening anaphylactoid reactions but the mechanisms remain unclear. We have now investigated the possibility that drug-specific IgE antibodies are involved by using an alcuronium-carrier complex in a radioimmunoassay with patients' sera. Alcuronium-reactive antibodies were found in five drug-sensitive subjects and most of the antibodies cross-reacted with other muscle relaxants and with a variety of apparently structurally unrelated drugs. Structure-activity studies designed to explore the molecular basis of the antibody binding established that quaternary and tertiary ammonium ions were the complementary allergenic sites on the reactive drugs. These structures occur widely in many drugs but also in foods, cosmetics, disinfectants and industrial materials. Hence, there would seem to be ample opportunity for sensitive individuals to come into contact with and synthesize IgE antibodies to these unusual, and previously unsuspected, antigenic determinants.

Anaphylactoid response to intravenous tubocurarine

A case of severe anaphylactoid reaction to tubocurarine in a 42-year-old female is described. This is particularly notable as there was no history of past allergies or of previous exposure to the drug.

The influences of andrenotropic drugs and noradrenaline on the histamine release in cardiac anaphylaxis in vitro

1. The regional distribution (auricles, ventricles and septum) of histamine and its release during anaphylaxis were studied in isolated perfused guinea-pig hearts.2. The highest value of histamine content was found in the right auricle, the lowest in the left ventricle and septum, both in normal hearts, and in the hearts subjected to anaphylaxis.3. The fraction of the total histamine released in the course of 24 min by antigen was 50%. The fraction released from the different regions of the heart was similar. No evidence was found for release of 5-hydroxytryptamine.4. A relation was found between the distribution of mast cells and the tissue concentration of histamine. The highest number of mast cells per unit area was found in the right auricle; the lowest in the left ventricle.5. The histamine release by antigen was reduced by previous treatment with (+)-tubocurarine; the histamine release by (+)-tubocurarine was depressed by previous challenge of the heart with antigen.6. Reserpine reduces histamine release. Perfusion of reserpine-treated hearts with noradrenaline partially restored histamine release.7. beta-Adrenergic blocking agents (dichloroisoproterenol and pronethalol) reduced histamine release.8. The drugs tested did not modify the tissue concentration of histamine.9. The possibility of a modulating activity of catecholamines on histamine release in cardiac anaphylaxis is discussed.

A method of estimating histamine in plasma

The method is intended for the estimation of minute quantities of histamine in blood plasma. A neutralized trichloracetic acid extract of plasma is adsorbed at pH 8 on a column prepared by mixing a quantity of the cationic exchange resin Amberlite XE-64 with powdered cellulose as a supporting medium. Histamine is adsorbed but N-acetylhistamine is not: the amines can therefore be estimated independently. Elution of the histamine is by displacement with HCl. The eluate is converted into the solution for bioassay on the superfused guinea-pig ileum.In recovery experiments histamine was added in the range 25 to 100 ng. to solutions of known composition and to plasma (5 ml.) obtained from man and the cat. The mean recovery in this range for histamine added to plasma was 82.5%+/-2 S.E. (17 estimations).The histamine equivalent of human plasma obtained from the antecubital vein was found to be less than 1 ng./ml.It was possible by this method to follow the concentration of histamine in the arterial plasma of the cat when histamine was infused intravenously at a rate of 330 ng./kg./min. There was no perceptible change in the arterial blood pressure during the infusion, but the plasma histamine rose from <0.3 ng./ml. to 3.4 ng./ml. (mean of 2 estimations).