Induction of human cutaneous mast cell degranulation by opiates and endogenous opioid peptides: evidence for opiate and nonopiate receptor participation

In order to examine the capacity of pharmacologically useful opiates to stimulate human mast cell secretion, subjects were skin tested with morphine, codeine, or meperidine hydrochloride. All three agents acted equipotently in eliciting positive immediate skin reactions from all subjects tested. Each agent demonstrated 10 mm of net whealing at 5 to 10 micrograms base (16.7 to 40.4 nmol) injected intradermally. The ability to elicit immediate skin test reactions with endogenous opioid peptides was examined with the use of dynorphin, [D-Ala, 2-D-Leu5] enkephalin, beta-endorphin, and morphiceptin . All four compounds induced wheal-and-flare reactions with the order of potency: dynorphin, greater than beta-endorphin, and greater than [D-Ala, 2-D-Leu5] enkephalin approximately equal to morphiceptin at dose ranges of 0.3 to 8.45 nmol. The inhibition of reactivity by hydroxyzine and the demonstration of mast cell degranulation by electron microscopy suggest that the immediate skin responses to opioid stimulation occur as a consequence of mast cell degranulation. Experiments with the opioid receptor antagonist, naloxone, suggest that both opioid and nonopioid receptors may be involved. These results imply that endogenous opioid peptides possibly may play a role in mast cell function and/or degradulation .

Opiate-sensitivity: clinical characteristics and the role of skin prick testing

BACKGROUND

The value of skin prick testing in opiate-sensitive individuals is uncertain as opiates cause non-specific weals by direct degranulation of mast cells.

OBJECTIVE

To define whether skin prick test (SPT) responses to opiates in opiate-sensitive individuals are different to those seen in the normal population and to describe the clinical characteristics of this group of subjects.

METHODS

The SPT responses of eight opiate-sensitive subjects to morphine 10 mg/mL, pethidine (meperidine) 50 mg/mL and papaveretum 15.4 mg/mL at four different concentrations (undiluted, 1/10, 1/50 and 1/100) were compared with the responses of 100 (32 atopic) non-opiate-sensitive control subjects. Four of the opiate-sensitive subjects had a clinical history of asthma, rhinitis or urticaria on occupational exposure to morphine. One subject developed urticaria with codeine, one developed urticaria and asthma with morphine and diamorphine and two subjects reacted to intravenous papaveretum with anaphylaxis or urticaria. Five out of the eight cases had opiate sensitivity confirmed by single-blind placebo-controlled oral challenge.

RESULTS

Skin prick tests to all three opiates were not significantly different when the eight opiate-sensitive subjects were compared with either the entire normal control group or the subgroup of 47 definite opiate-tolerant controls that had previously received opiates for clinical indications. Furthermore, there were no significant differences in size of opiate SPT responses between atopic and non-atopic control subjects. In the control subjects, there was a positive correlation in SPT weal size between the three opiates.

CONCLUSION

Skin prick testing is not useful in the diagnosis of opiate sensitivity and placebo-controlled challenge should be considered.

In vitro evaluation of fentanyl and meperidine for immunomodulatory activity

Exposure to drugs, either ethical pharmaceuticals or illicit street drugs, often results in medical complications, including alterations in the immune system. Among the drugs associated with immunomodulatory potential are the analgesics fentanyl and meperidine. The purpose of this study was to determine the potential of these drugs to alter immunological parameters subsequent to in vitro exposure at a range of concentrations. This potential immunotoxicity was assessed using a series of in vitro assays measuring B-lymphocyte proliferation, cytokine production by T-helper lymphocytes, T-lymphocyte cytolytic function, natural killer (NK) cell function, and macrophage function. Exposure to these analgesics was associated with a differential suppression of interleukin-4 production by T-cells, as well as a more generalized suppression of cytokine production by macrophages. In addition, T-cell cytolytic activity was suppressed at high drug concentrations. B-cell proliferation and NK cell activity were also inhibited, but to a lesser degree than noted with T-cell function. Addition of naltrexone to the cultures did not reverse these alterations in immune function, suggesting that these changes are not mediated via opioid receptors.

The anti-inflammatory effect of opioids

The anti-inflammatory activity of two novel opioids PM and PO as well as of pethidine was studied. The mouse paw edema, induced by various phlogistic agents, was significantly inhibited after the administration of opioids, fact that was independent of their antioxidant properties. The anti-inflammatory action of the above opioids was not reversed by naloxone. These results suggest that a variety of complex regulatory activities may be performed by opioid agonists via naloxone-sensitive or naloxone insensitive receptors on inflammatory cells, directly or indirectly by the inhibition of cytokines and mediators involved in inflammation.

Production and characterization of antibodies to meperidine

A mepridine-bovine serum albumin (Mep-BSA) conjugate with 15-20 moles of meperidine per mole of BSA was synthesized and characterized. Rabbits immunized with Mep-BSA produced antibodies that were assayed utilizing saturated ammonium sulfate to separate 3H-meperidine (3H-M) bound to antibody from free 3H-M. Antibody specificity was assessed by competitive inhibition studies. The nanomoles of inhibitor required to decrease the binding of 3H-M by 50% were: meperidine .046; meperidine acid, 3.2; alphaprodine, 7.8; dextromethorphan, 20; codeine, 50; and morphine 55. The sensitivity of the assay is approximately 30 ng/ml; sufficient for pharmacokinetic studies of the disposition of meperidine in man.

The production and characterization of antibodies reactive with meperidine

Meperidinic acid was converted to O-meperidinyl-glycollic acid and covalently attached to bovine serum albumin. Rabbits injected with this conjugate produced antibodies reactive with meperidine which were measured by the ammonium sulfate method. The specificities of these antisera were studied by competitive inhibition of the binding of 100 pmol/ml of 3H-meperidine to antibody by the prior addition of increasing concentrations of various unlabeled compounds. The concentrations in nanomoles per milliliter of various unlabeled opiods required to inhibit 3H-meperidine binding by 50% (I50) were: meperidine, 0.08; O-meperidinyl-glycollic acid, 1.7; methadone, 580; heroin, 1750; codeine, 2600; and morphine, 4200. Several psychopharmacologically active compounds were found to have I50 values comparable to the nonmeperidine opioids: hydroxyzine. HCl, 460; propoxyphene, 4,500; diazepam, 6,500; and cocaine, 10,800. The metabolites of meperidine exhibited the following I50 values: normeperidine, 0.7; meperidinic acid and normeperidinic acid, 210. A radioimmunoassay for meperidine which employs this antiserum was shown to be approximately 100 times more sensitive than the spectrophotometric method of Burns et al. (J. Pharmacol. Exp Ther. 114: 289-293, 1955). In this assay only normeperidine and some of the meperidine congeners might be expected to interfere with the measurement of meperidine. The degree of normeperidine interference was shown to be comparable to that present in the existing assay method.

The production and characterization of antibodies reactive with meperidine

Meperidinic acid was converted to O-meperidinyl-glycollic acid and covalently attached to bovine serum albumin. Rabbits injected with this conjugate produced antibodies reactive with meperidine which were measured by the ammonium sulfate method. The specificities of these antisera were studied by competitive inhibition of the binding of 100 pmol/ml of 3H-meperidine to antibody by the prior addition of increasing concentrations of various unlabeled compounds. The concentrations in nanomoles per milliliter of various unlabeled opiods required to inhibit 3H-meperidine binding by 50% (I50) were: meperidine, 0.08; O-meperidinyl-glycollic acid, 1.7; methadone, 580; heroin, 1750; codeine, 2600; and morphine, 4200. Several psychopharmacologically active compounds were found to have I50 values comparable to the nonmeperidine opioids: hydroxyzine-HC1, 460; propoxyphene, 4,500; diazepam, 6,500; and cocaine, 10,800. The metabolites of meperidine exhibited the following I50 values: normeperidine, 0.7; meperidinic acid and normeperidinic acid, 210. A radioimmunoassay for meperidine which employs this antiserum was shown to be approximately 100 times more sensitive than the spectrophotometric method of Burns et al. (J. Pharmacol. Exp. Ther. 114:289-293, 1955). In this assay only normeperidine and some of the meperidine congeners might be expected to interfere with the measurement of meperidine. The degree of normeperidine interference was shown to be comparable to that present in the existing assay method.

The specificity of antimorphine and antimeperidine antibodies and their reactivity with opioid peptides

The specificity of antimorphine and antimeperidine antisera was measured by competitive displacement of immunizing radiolabeled haptens. Antimorphine antisera demonstrated a high degree of specificity for a conformation of the phenylpiperidine moiety contained within the structures of morphine and its congeners of the morphinan and benzomorphan series. Antimeperidine antisera demonstrated a high degree of specificity for a different conformation of the phenylpiperidine moiety represented within the structures of meperidine and its semisynthetic derivatives. The reactivity of methionine- and leucine-enkephalin, several synthetic enkephalin analogs, and alpha- and beta-endorphin with the antibodies was tested using purified immunoglobulin G in order to avoid serum-induced proteolysis. No significant cross-reactivity of antimorphine antibodies with any of the opioid peptides was detected. All of the opioid peptides tested exhibited weak but immunologically specific cross-reactivity with antimeperidine antibodies. These findings suggest that conformations analogous to the phenylpiperidine moiety in morphine as have been proposed for [Tyr1] in opioid peptides do not appear to be present as measured by immunochemical methods. A conformation with weak stereochemical similarity to the phenylpeperidine moiety in meperidine does appear to be present. The possible homologies between [Phe4] of opioid peptides, meperidine and hydrophobic side chains of certain oripavine derivatives are discussed.