Membrane-receptor disorders in adrenergic and histaminergic systems under peroxide exposure in bronchial asthma patients

AIM: To characterize membrane-receptor peculiarities in adrenergic and histaminergic systems under model peroxide effect in bronchial asthma (BA). MATERIALS AND METHODS: 172 patients with BA, 17 patients with nonpulmonary allergy, 38 healthy men and 19 healthy blood relatives of BA patients were examined for peroxide resistance of erythrocytic membrane to modulation with adrenergic and histaminergic agonists and antagonists. The modified method by A. A. Abramov and A. A. Pokrovsky was used. RESULTS: In atopic BA the phenomenon of inversion of the effect of beta-adrenoblocker (obzidan) and of combined effect of histamine and H1-antagonist (dimedrol) was revealed. The same phenomenon was registered at the stage of preasthma and at the preclinical stage of BA. In infection-dependent BA this phenomenon occurred less frequently being rare in remission. In both BA variants the shift of H1/H2-histaminergic balance to increased H1-activity exists which is more significant in atopic BA, preasthma and preclinical BA. CONCLUSION: Peroxide effects modelled on red cell membranes enabled to characterize reactivity of adrenergic and histaminergic systems not only in BA but also in preasthma and preclinical BA.     

Peculiarities of cell reception in bronchial asthma patients with bronchial hyperreactivity to hyperosmolar provocation

AIM: To investigate characteristics of the cell receptor systems in bronchial asthma (BA) patients with bronchial hyperreactivity (BHR) induced by hyperosmolar provocation. MATERIALS AND METHODS: 15 patients with BA, in most cases atopic, in remission were studied. The bronchoprovocative test (BPT) with ultrasonically nebulized 3.6% hypertonic NaCl solution (UNHS) FEV1-control was performed. Cell receptors reactivity was analysed on the model of erythrocyte resistance (ER) to hyperosmolar provocation (HP) under the modulation by adrenergic and histaminergic agents. RESULTS: It was revealed that ER was significantly higher (p < 0.05) in BA patients with BHR to UNHS under histaminergic modulation, but ER did not differ in BA patients with or without BHR to UNHS under the adrenergic modulation. The correlation was found between DFEV1 on BPT and magnitude of ER to HP under the blockade of H1-histaminergic receptors (r = 0.72; p < 0.02). CONCLUSION: The development of BHR to hyperosmolar stimulus may be due primarily to disturbance of histaminergic receptor system.     

Surface architectonics and cytoskeleton of erythrocytes and their modulation by adrenergic agents in patients with bronchial asthma

AIM: To evaluate erythrocyte surface architectonics and cytoskeleton in bronchial asthma (BA) under modulation of adrenergic agents. MATERIAL AND METHODS: 24 healthy persons, 61 patients with bronchial asthma (BA) were examined. Of them, 28 patients had allergic BA (ABA) and 33 ones had nonallergic BA (NABA). Erythrocyte surface architectonics was studied by phase-contrast microscopy. Fixation in 0.5% solution of glutar aldehyde was used, preparation "squashed drop" was prepared. In all preparations adrenalin hydrochloride and obzidan were used in equimolar final concentrations of 4.10(-5) M. The mean morphologic index of transformation that reflects the shift to stomatocytosis or to echinocytosis was estimated to characterize integrally erythrocyte surface architectonics. The cytoskeleton was studied by the modified method of Chentosov's et al. The integral optic density was evaluated on imaging analyzer of Ista-Videotest company (St-Petersburg). RESULTS: In healthy persons there was a correlation between erythrocyte surface architectonics and cytoskeleton under modulation of adrenergic system. Adrenalin-induced decrease of cytoskeletal proteins correlated with the shift to stomatocytosis. In NABA erythrocyte surface architectonics was characterized by a pronounced shift to stomatocytosis. This shift was accompanied with the most pronounced decrease of cytoskeletal proteins and it reduced in remission. In ABA manifestation of the shift was minimal and did not depend on the phase of the disease. In ABA no changes in erythrocyte surface architectonics in the presence of adrenalin were revealed. In the same conditions a decrease in cytoskeletal proteins was found. CONCLUSION: A correlation was found between erythrocyte surface architectonics and cytoskeleton in healthy persons. In ABA, under modulation of adrenergic system by adrenalin dissociation was revealed between receptor and cytoskeletal mechanisms of cell form induction. This dissociation does not depend on the phase of the disease and is thought to be one of the important postreceptor disorders typical for this variant of the disease.     

Disturbance of apoptosis of peripheral blood lymphocytes in different variants of bronchial asthma

AIM: To reveal disturbances of peripheral blood lymphocytes apoptosis in different variants of bronchial asthma (BA). MATERIAL AND METHODS: Apoptosis was studied in 20 healthy subjects, 70 BA patients: 32 patients with allergic BA (ABA) and 26 patients with non-allergic (NABA), 12 patients with BA treated with oral glucocorticosteroids. The following parameters of apoptosis were assessed: cell readiness for apoptosis (expression of CD95/Fas/APO-1 receptors), an early reversible stage of apoptosis (expression of phosphatidylserine on outer leaflet of lymphocyte membrane) and a late stage of apoptosis (the key effector caspase 3 activity). RESULTS: ABA is characterized by increased peripheral blood lymphocytes resistance to apoptosis: a decrease in expression of CD95/Fas/APO-1 receptors and phosphatidylserine on lymphocyte surface and caspase 3 activity. NABA is characterized by peripheral blood lymphocyte apoptosis activation at all stages: high expression of CD95/Fas/APO-1 receptors, expression of phosphatidylserine and caspase 3 activity. BA patients on systemic glucocorticosteroids are characterized by maximal expression of CD95/Fas/APO-1 receptors and phosphatidylserine on lymphocyte surface and the highest caspase 3 activity. CONCLUSION: The findings allow more accurate definition of the features of peripheral blood lymphocytes apoptosis in different variants of bronchial asthma and characteristics of relations between disturbed apoptosis and inflammation. Disturbances of apoptosis may be of pathogenetic importance in persistence ofallergic inflammation.     

Bronchomotor effects of cardioselective beta 1-adrenoblockaders in patients with bronchial asthma

A study was made of the effect of beta 1-adrenoblockers (metoprolol, atenolol, talinolol) on bronchial patency in patients with concomitant bronchial asthma (BA) under acute drug use and in the course of continuous therapy. Broncho-obstructive complications occurring in part of the patients were not associated with the disease gravity or with the pathogenetic variety of BA. Besides, they were not associated with the drug dose either (use was made of the mean therapeutic dosage range). The rate and the intensity of bronchial patency abnormalities occurring in the course of the continuous treatment with beta 1-adrenoblockers (with metoprolol, in particular) depended on the initial status of the adrenergic regulation of the body. Significant disorders of bronchial patency including clinically marked ones were naturally observed with initially low excretion of cAMP in the morning portion of urine (less than 3 mmole/1).     

Hydrogen peroxide--a marker for respiratory tract inflammation in patients with bronchial asthma

AIM: To test H2O2 as a marker of respiratory tract inflammation in patients with bronchial asthma (BA). MATERIAL AND METHODS: The study entered 70 patients (20 males and 50 females) with atopic asthma (AA) aged 18 to 62 years (mean age 32.6 years). H2O2 concentration in the expired air (CEA) was determined spectrophotometrically (Gallati & Pracht, 1985), content of eosinophilic cationic protein (ECP) in blood--with radioimmunoassay kits (Pharmacia & Upjohn, Sweden). Forced expiratory volume per 1 second (FEV1) was used for assessment of severity of bronchial obstruction. Bronchial hyperreactivity was studied by means of the histamine bronchoprovocative test. RESULTS: H2O2 in CEA in BA patients was higher than in healthy subjects (0.127 +/- 0.010 microm/l vs 0.024 +/- 0.004 microm/l). H2O2 concentration significantly correlates with FEV1 (r = -0.449; p < 0.001), bronchial hyperreactivity to histamine (rs = -0.382; p < 0.05) and ECP in blood plasma(r = 0.625; p < 0.01). CONCLUSION: It was proved possible to use H2O2 in CEA for evaluation of respiratory inflammation in BA patients.     

The histaminergic system: a target for innovative treatments of cognitive deficits

The central effects of histamine are mediated by H(1), H(2) and H(3) receptors. The H(3) receptor inhibits histamine release in brain. Therefore, H(3) receptor inverse agonists, by suppressing this brake, enhance histamine neuron activity. The histaminergic system plays a major role in cognition and H(3) receptor inverse agonists are expected to be a potential therapeutics for cognitive deficits of Alzheimer's disease (AD). They are eagerly awaited inasmuch as other treatments of the disease, such as tacrine or memantine, also enhance, through different mechanisms, histaminergic neurotransmission. An important loss of histaminergic neurons has been observed in AD. In contrast, levels of the histamine metabolite in the CSF of AD patients show that their global activity is decreased by only 25%. This indicates that activating histamine neurons in AD can be envisaged.     

Direct effect of parathyroid hormone on rat uterine contraction

Synthetic bovine parathyroid hormone containing the 1-34 NH2 terminal amino acids [bPTH-(1-34)] is capable of inhibiting stimulated uterine contraction. The purpose of the present investigation is to determine whether the inhibitory action of bPTH-(1-34) is a direct action of the hormone fragment. The effect of different synthetic preparations of bPTH-(1-34), salmon calcitonin, corticotropin-inhibiting peptide and bovine serum albumin on oxytocin-stimulated uterine contraction was determined. In addition, the effects of atropine, propranolol, phentolamine, pyrilamine, cimetidine and the prostaglandin synthetase inhibitor indomethacin on the inhibitory action of bPTH-(1-34) on uterine contraction was determined. Both synthetic preparations of bPTH-(1-34) inhibited oxytocin-initiated contractions similarly. Salmon calcitonin, corticotropin-inhibiting peptide, and bovine serum albumin did not alter oxytocin-stimulated uterine contractions. The salmon calcitonin also did not alter the ability of bPTH-(1-34) to exert its inhibitory effect on uterine contraction. Cholinergic, alpha and beta adrenergic, histaminergic (H1 and H2) and prostaglandin synthetase inhibitors did not alter the action of bPTH-(1-34). These results suggest that the action of bPTH-(1-34) is 1) not due to the presence of a contaminant in the synthetic hormone preparation and 2) that the effect could be due to a direct action effect of the hormone fragment on uterine tissue.     

Regional variation in acute vascular homologous tachyphylaxis.

The development of tachyphylaxis or desensitization in a tissue upon repeated application of an agonist is a well-established phenomenon. To investigate the possible basis of vascular homologous tachyphylaxis, vasomotor responses in isolated cerebral and peripheral blood vessels from the cat, dog and rabbit upon repeated application of several agonists were examined using in vitro tissue bath techniques. Tachyphylaxis to vasodilator responses developed to repeated application of vasoactive intestinal polypeptide (VIP) but not to beta adrenergic agonist, forskolin, 8-bromo-cyclic AMP, sodium nitroprusside or 8-bromo-cyclic GMP in feline cerebral arteries. The tachyphylaxis to VIP-induced responses varied among regions and was greatest in the internal carotid artery (ICA), followed by the middle cerebral artery and least in the basilar artery (BA). Cerebral arteries also developed significant tachyphylaxis to constriction induced by repeated applications of neuropeptide Y (NPY), alpha-1 adrenergic agonist, but not to alpha-2 adrenergic agonist, acetylcholine (ACh) or KCl. The tachyphylaxis to constrictions induced by repeated application of neuropeptide Y (NPY) also varied among regions, but was different from that induced by VIP; it was greatest in the BA, followed by the middle cerebral artery and least in the ICA. Similar results were obtained in arteries without endothelial cells. The density of regional innervation of NPY-immunoreactive fibers, which is densest in ICA and sparsest in BA, parallels that of VIP-immunoreactive fibers in these three regions. There is no positive correlation between density of catecholamine fluorescence fibers and degree of tachyphylaxis to noradrenaline-induced constriction in cat ICA, dog saphenous arteries and rabbit ear arteries either.(ABSTRACT TRUNCATED AT 250 WORDS)     

Effect of sodium hypochlorite on neuroregulatory systems in acute psychotropic drug poisoning

The effect of sodium hypochlorite (SHC) on neuroregulatory systems was studied in patients with acute poisoning with psychotropic drugs infused intravenously as components of infusion therapy. Infusion therapy alone or in complex with SHC does not affect the cholinergic system of the organism. The corrective effect of SHC on the sympathetic, serotonin- and histaminergic systems was more pronounced in comparison with infusion therapy and was the most expressed on day 2 after the treatment.     

The effect of theophylline on purine receptor function in bronchial asthma patients]

A study was made of purine receptors (PR) in healthy subjects and bronchial asthma (BA) patients before and after theophylline (TP) treatment. BA patients demonstrated a significant lowering of the binding sites of A2PR and a tendency toward the rise of the number of A1PR on peripheral blood lymphocytes as compared to the healthy subjects. As a result of TP therapy for 3 weeks, the number of A2PR increased in 69% and the number of A1PR fell in 50% of the patients. The efficacy of TP pharmacotherapy depended significantly on the increment of the binding sites of A2PR. The growth of the number of A2PR was recorded in the groups of patients with a beneficial and satisfactory effect of the treatment.     

Adrenergic vascular reactivity in elderly hypertensive patients with orthostatic disorders

Vascular adrenergic reactivity was studied in 100 healthy persons and 222 elderly patients with stage II essential hypertension at high risk of complications. With age, the rate of orthostatic hypotension rises. This hypotension in the elderly hypertensive patients is caused by reduced adrenergic reactivity of venous microvessels.     

Clinico-functional evaluation of arterial rigidity in bronchial asthma

Vascular disturbances play an important role in the pathogenesis of bronchial asthma (BA). Presently, study of vascular mechanical properties, arterial rigidity in particular, is of great interest in terms of evaluation of functional condition of the cardiovascular system. It is not clear yet, whether arterial rigidity increases in patients with bronchial asthma, and what role it can play in its pathogenesis. Fifty-four patients were examined with non-invasive arteriography (arteriographer TensioClinic TL 1, TensioMed, Hungary). Aortal rigidity was in general significantly higher in patients with BA exacerbation vs. healthy controls. This was expressed by a higher pulse wave velocity in the aorta (PWVA) and augmentation index (AI) in severe and moderate BA. PWVA in BA was almost twice higher in BA patients compared with healthy people. The ratio of coronary perfusion indices (systolic and diastolic area index; SAI and DAI) was biased towards SAI. Regardless of the degree of an increase in arterial vascular rigidity in BA exacerbation, PWVA, AI, and SAI/DAI significantly improved and approximated normal values during remission, which demonstrate a transient character of these changes. In patients with severe BA AI and SAI/DAI ration were lower than in patients with moderate BA and healthy individuals, which is connected with adaptation phenomena. Correlation analysis showed that an increase in arterial rigidity is connected mostly with the degree of ventilation disorder and hypoxia as well as with the duration and severity of the disease. Further research in this direction will make it possible to know more about the exact pathophysiological mechanisms of vascular dysfunction in BA.     

Antigen- and receptor-driven regulatory mechanisms. I. Induction of suppressor T cells with anti-idiotypic antibodies

Delayed-type hypersensitivity (DTH) to the azobenzenearsonate (ABA) hapten can be readily induced in A/J mice injecting ABA-coupled syngeneic spleen cells subcutaneously. To further characterize this T-cell-dependent immunological phenomenon, the effect of passively administered anti-cross-reactive idiotype common to anti-ABA antibodies of A/J mice (CRI) antibodies on the development of ABA-specific DTH was investigated. Animals given daily injections (of minute amounts) of anti-CRI antibodies subsequent to immunization with ABA-coupled cells show significant reduction of ABA specific responses. This inhibition is antigen specific and requires the intact immunoglobulin molecule, as F(ab')2 treatments were ineffective in suppressing the reaction. Investigations of the mechanism of the anti-CRI-induced suppression of ABA DTH revealed that the observed suppression is a result of the activation of suppressor cells. Spleen cells taken from animals which received anti-CRI antibodies were able to adoptively transfer suppression to naive recipients. This suppression was shown to be mediated by T cells, as anti-Thy1.2 plus complement completely abrogated the transfer of suppression. In addition, animals pretreated with low doses of cyclophosphamide were not suppressed by the administration of anti-CRI antibodies. The genetic restriction of anti-CRI-induced suppression was demonstrated. Antibodies to the major cross-reactive idiotype, (CRI) associated with anti-ABA antibodies in A/J mice were unable to suppress the development of DTH to ABA in BALB/c mice (H-2d, Igh-1a). Such antibodies were, however, fully active in suppressing ABA DTH in the allotype-congenic C.AL-20 strain which has an allotype (Igh-1d) similar to that of A/J (Igh-1e) on a BALB/c background, and which produces humoral antibodies with the CRI.     

Identification and characterization of α1- and β2-adrenergic receptors in human liver

Adrenergic receptors were identified in healthy human hepatic tissue from thirty-nine subjects undergoing elective abdominal surgery by using the specific alpha 1-antagonist [3H]-prazosin and the beta adrenergic antagonist [3H]-dihydroalprenolol ([3H]-DHA). [3H]-prazosin binding to plasma membranes was rapid, of high affinity, saturable and stereospecific with a maximal binding capacity (Bmax) of 74.1 +/- 5.5 fmol mg-1 of protein. The displacement curve for (-)-norepinephrine was better explained by a one-site binding and after addition of GTP 0.1 mM the curve was not right-shifted, suggesting the majority of alpha receptors in healthy human liver are of the alpha 1 subtype and not linked to a GTP-binding protein. [3H]-DHA binding to liver plasma membranes was also rapid, of high affinity, saturable and stereospecific with a Bmax 96.5 +/- 10.3 fmol mg-1 of protein of receptors. Computer aided analysis of the displacement curve of ICI 118,551, a subtype selective beta 2-antagonist (IC50 = 62 +/- 2 nM), indicated a one-site binding, thus, showing that beta adrenergic receptors are of the beta 2 subtype. The displacement curve of [3H]-DHA for (-)-isoproterenol was right shifted by GTP indicating that beta 2 adrenergic receptors are linked to a GTP-binding protein in human liver. These results indicate that alpha 1- and beta 2-receptors co-exist in human liver but only beta 2-receptors are linked to a GTP-binding protein.     

The physiological and pathophysiological roles of neuronal histamine: an insight from human positron emission tomography studies

Histamine neurons are exclusively located in the posterior hypothalamus, and project their fibers to almost all regions of the human brain. Although a significant amount of research has been done to clarify the functions of the histaminergic neuron system in animals, a few studies have been reported on the roles of this system in the human brain. In past studies, we have been able to clarify some of the functions of histamine neurons using different methods, such as histamine-related gene knockout mice or human positron emission tomography (PET). The histaminergic neuron system is known to modulate wakefulness, the sleep-wake cycle, appetite control, learning, memory and emotion. Accordingly we have proposed that histamine neurons have a dual effect on the CNS, with both stimulatory and suppressive actions. As a stimulator, neuronal histamine is one of the most important systems that stimulate and maintain wakefulness. Brain histamine also functions as a suppressor in bioprotection against various noxious and unfavorable stimuli of convulsion, drug sensitization, denervation supersensitivity, ischemic lesions and stress susceptibility. This review summarizes our works on the functions of histamine neurons using human PET studies, including the development of radiolabeled tracers for histamine H1 receptors (H1R: (11)C-doxepin and (11)C-pyrilamine), PET measurements of H1R in depression, schizophrenia, and Alzheimer's disease (AD), and studies on the sedative effects of antihistamines using H(2)(15)O and H1R occupancy in the human brain. These molecular and functional PET studies in humans are useful for drug development in this millennium.     

The effects of alpha adrenergic agents on human platelet aggregation.

The effects of alpha adrenergic agonists and antagonists on human in vitro platelet aggregation were studied to characterize further the platelet alpha adrenergic receptor. Aggregation induced by ADP and U46619; a stable prostaglandin endoperoxide analog, was potentiated by alpha adrenergic agonists, an effect which was completely blocked by the alpha adrenergic antagonist phentolamine (1 X 10(-6) M) but not by prazosin (1 X 10(-6) M). The order of potency for the alpha adrenergic agonists in potentiating ADP-induced aggregation was clonidine greater than or equal to epinephrine greater than alpha-methylnorepinephrine greater than norepinephrine greater than phenylephrine greater than methoxamine. Epinephrine-induced platelet aggregation was blocked by phentolamine, yohimbine, dihydroergotamine, clonidine and lofexidine but not by phenoxybenzamine (1 X 10(-5) M). These findings suggest that: 1)clonidine and lofexidine are partial agonists and 2) that the alpha adrenergic receptor of the platelet is different from the classical postsynaptic alpha adrenergic receptor and more closely resembles presynaptic alpha adrenergic receptors.     

BF2.649 [1-{3-[3-(4-Chlorophenyl)propoxy]propyl}piperidine, hydrochloride], a nonimidazole inverse agonist/antagonist at the human histamine H3 receptor: Preclinical pharmacology

Histamine H3 receptor inverse agonists are known to enhance the activity of histaminergic neurons in brain and thereby promote vigilance and cognition. 1-{3-[3-(4-Chlorophenyl)propoxy]propyl}piperidine, hydrochloride (BF2.649) is a novel, potent, and selective nonimidazole inverse agonist at the recombinant human H3 receptor. On the stimulation of guanosine 5'-O-(3-[35S]thio)triphosphate binding to this receptor, BF2.649 behaved as a competitive antagonist with a Ki value of 0.16 nM and as an inverse agonist with an EC50 value of 1.5 nM and an intrinsic activity approximately 50% higher than that of ciproxifan. Its in vitro potency was approximately 6 times lower at the rodent receptor. In mice, the oral bioavailability coefficient, i.e., the ratio of plasma areas under the curve after oral and i.v. administrations, respectively, was 84%. BF2.649 dose dependently enhanced tele-methylhistamine levels in mouse brain, an index of histaminergic neuron activity, with an ED50 value of 1.6 mg/kg p.o., a response that persisted after repeated administrations for 17 days. In rats, the drug enhanced dopamine and acetylcholine levels in microdialysates of the prefrontal cortex. In cats, it markedly enhanced wakefulness at the expense of sleep states and also enhanced fast cortical rhythms of the electroencephalogram, known to be associated with improved vigilance. On the two-trial object recognition test in mice, a promnesiant effect was shown regarding either scopolamine-induced or natural forgetting. These preclinical data suggest that BF2.649 is a valuable drug candidate to be developed in wakefulness or memory deficits and other cognitive disorders.     

Increased vascular alpha1-adrenergic sensitivity in patients with renal failure: receiving recombinant erythropoeitin

End stage renal disease (ESRD) is associated with altered hemodynamic regulation as a result of the pathophysiology or treatment of renal failure. Hypertension, common among dialysis patients, is a recognized complication of recombinant human erythropoietin (rHuEPO) therapy. We determined vascular adrenergic and nitric-oxide-mediated responsiveness in 7 patients with established ESRD on rHuEPO treatment and in 13 healthy volunteers using the dorsal hand vein technique. Sensitivity to the alpha1-adrenergic selective agonist phenylephrine was significantly increased in patients with ESRD on rHuEPO. The mean dose of phenylephrine producing 50% venoconstriction (ED50) was 38 +/- 1.6 ng/min in patients with ESRD and 135 +/- 1.3 ng/min in healthy volunteers-almost a 4-fold increase in dose, P = 0.01. In contrast, maximal venodilation mediated by bradykinin, an endothelium-dependent vasodilator, was not different in the 2 groups. To determine whether rHuEPO has a direct vasoconstrictor effect, we studied venous responsiveness to local infusions of rHuEPO in healthy volunteers. Increasing concentrations of rHuEPO produced no vasoconstriction in hand veins of healthy volunteers. These results suggest that vascular responsiveness to alpha-adrenergic stimulation in patients with ESRD on rHuEPO is increased whereas bradykinin-mediated venodilation remains intact. This increase in vascular alpha-adrenergic responsiveness may contribute to the increased peripheral vascular resistance and hypertension seen in patients with ESRD on rHuEPO.