The health potential of neighborhoods: A population-wide study in the Netherlands.

BACKGROUND: While differences in population health across neighborhoods with different socioeconomic characteristics are well documented, health disparities across neighborhoods with similar socioeconomic characteristics are less well understood. We aimed to estimate population health inequalities, both within and between neighborhoods with similar socioeconomic status, and assessed the association of neighborhood characteristics and socioeconomic spillover effects from adjacent neighborhoods. METHODS: Based on Dutch whole-population data we determined the percentage of inhabitants with good or very good self-assessed health (SAH) and the percentage of inhabitants with at least one chronic disease (CD) in 11,504 neighborhoods. Neighborhoods were classified by quintiles of a composite neighborhoods socioeconomic status score (NSES). A set of spatial models was estimated accounting for spatial effects in the dependent, independent, and error components of the model. RESULTS: Substantial population health disparities in SAH and CD both within and between neighborhoods NSES quintiles were observed, with the largest SAH variance in the lowest NSES group. Neighborhoods adjacent to higher SES neighborhoods showed a higher SAH and a lower prevalence of CD. Projected impacts from the spatial regressions indicate how modest changes in NSES among the lowest socioeconomic neighborhoods can contribute to population health in both low- and high-SES neighborhoods. CONCLUSION: Population health differs substantially among neighborhoods with similar socioeconomic characteristics, which can partially be explained by a spatial socio-economic spillover effect.

Gender differences in the mental health impact of the COVID-19 lockdown: Longitudinal evidence from the Netherlands.

Recent contributions highlighted gender differences in the mental health consequences of COVID-19 lockdowns. However, their cross-sectional designs cannot differentiate between pre-existing gender differences and differences induced by lockdowns. Estimating fixed-effects models using longitudinal data from the Lifelines biobank and cohort study with repeated mental health measurements throughout the lockdown, we overcome this caveat. Significant gender differences in mental health during the lockdown were found, where women experienced more depression symptoms and disorders and men experienced more anxiety symptoms and disorders stemming from the lockdown. Policymakers need to keep in mind that the COVID-19 lockdowns have different effects on mental health for men and women.

Regulation of plasma aldosterone levels by metoclopramide: a reappraisal of its mechanism from dopaminergic antagonism to serotonergic agonism.

It has been thought, since the late 1970s, that dopamine exerts a tonic suppression of plasma aldosterone levels in human subjects. This action, however, had not been established directly using dopamine and dopamine mimetic drugs, which do not, in fact, affect the aldosterone levels. Rather, the conclusion was arrived at indirectly, based on the increase in aldosterone levels seen with dopamine receptor blockers; metoclopramide in particular, considered at the time of its discovery in the 1960s to be a new generation dopamine antagonist. However, metoclopramide is not a pure drug and in fact, shows intermediate affinity at certain serotonin receptor subtypes. Studies have been recently carried out in human subjects on the role of serotonergic transmission in mediating the metoclopramide as an aldosterone secretagogue effect. Here we briefly review this work and attempt to reassess the action of metoclopramide as an aldosterone secretagogue, from dopamine D2 antagonism to serotonin 5-HT4 partial agonism.

Dopamine autoreceptor agonists: resolution and pharmacological activity of 2,6-diaminotetrahydrobenzothiazole and an aminothiazole analogue of apomorphine.

The enantiomers of the aminothiazole analogues of the known dopaminergic agonists apomorphine (1) and 2-aminohydroxytetralin (2) have been prepared. The absolute configurations of the enantiomers of 2,6-diaminotetrahydrobenzothiazole have been established by X-ray crystallographic analysis. Dopamine (DA) autoreceptor agonist activities of the compounds were evaluated. Testing revealed (-)-5, the S enantiomer, to be the most active compound tested (inhibition of GBL accelerated dopamine synthesis and inhibition of alpha-methyltyrosine-induced decline of DA). In addition (-)-5 does not exhibit stereotyped behavior, suggesting a pronounced selectivity for DA autoreceptors.

The dopamine agonist pramipexole scavenges hydroxyl free radicals induced by striatal application of 6-hydroxydopamine in rats: an in vivo microdialysis study.

Hydroxyl free radical production seems to play an important role in the pathogenesis of Parkinson's disease. In the present study, we investigated the dopamine agonists pramipexole and pergolide as well as the nitrone compound S-PBN (N-tert-butyl-alpha-(2-sulfophenyl)nitrone) to reduce hydroxyl radical formation. Microdialysis experiments were carried out in non-anaesthetized Wistar rats. Salicylate was incorporated into the perfusion fluid to measure indirectly hydroxyl radicals indicated by 2,3-dihydroxybenzoic acid (2,3-DHBA). Local perfusion with 0.2 or 2 nmol/2 microl/min 6-hydroxydopamine (6-OHDA) via the microdialysis probe significantly increased 2,3-DHBA levels 14-fold and 47-fold, respectively. Systemic application of either pergolide (0.05 mg/kg) or pramipexole (1 mg/kg) failed to significantly reduce 6-OHDA-induced hydroxyl radical production. In contrast, a 40 min pretreatment with pramipexole (2 and 10 nmol/2 microl/min via the probe) before onset of 6-OHDA perfusion, significantly attenuated 2, 3-DHBA levels compared with vehicle controls. S-PBN pretreatment (2 nmol/2 microl/min) was not effective to reduce 2,3-DHBA levels. In conclusion, pramipexole was able to reduce hydroxyl radical levels induced by 6-OHDA in vivo after local application. This property of pramipexole may be beneficial under conditions of enhanced hydroxyl radical formation in parkinsonian brains and may add to its well known dopamine D(2)-like receptor agonistic effects.

Biochemical and pharmacological studies on pramipexole, a potent and selective dopamine D2 receptor agonist.

Pramipexole (SND 919; 2-amino-4,5,6,7-tetrahydro-6-propyl-amino-benzthiazole- dihydrochloride) was tested for its agonistic activity at pre- and postsynaptic dopamine (DA) receptors. L-Dihydroxyphenylalanine (L-dopa) accumulation in the rat striatum and limbic system and the alpha-methyltyrosine-induced reduction of DA were inhibited. Both effects were fully antagonized by haloperidol but not by the selective DA D1 receptor antagonist SCH 23390. Pramipexole decreased the levels of DA metabolites dose dependently, whereas striatal DA levels remained unchanged. In mice, pramipexole (0.001-1 mg/kg s.c.) reduced exploratory locomotor activity. In rats with unilateral striatal lesions, only weak ipsilateral rotation was produced by pramipexole at the highest dose. However, in rats with unilateral lesions of the medial forebrain bundle, pramipexole potently induced contralateral circling (ED50 0.026 mg/kg s.c.). In the N-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) monkey model, pramipexole also had potent stimulatory effects. Finally, in haloperidol-sensitized monkeys, the substance did not elicit dyskinesia/dystonia when given alone, but rather inhibited those symptoms which had been induced by haloperidol (ED50 0.116 mg/kg i.m.). It is concluded that pramipexole has therapeutic potential for schizophrenic patients, as a result of its autoreceptor agonistic effects and its weak effects at normosensitive postsynaptic DA receptors. Furthermore, its potent stimulatory effects in DA-depleted animals suggest a possible use in the treatment of Parkinson's disease.

N-(3-acetylaminophenyl)piperazine hydrochloride (BEA 1654), a putative 5-HT1 agonist, causes constriction of arteriovenous anastomoses and dilatation of arterioles.

Using 3H-ligands and radioactive microspheres we studied the binding characteristics and the effects on the distribution of carotid arterial blood flow of n-(3-acetylaminophenyl)piperazine hydrochloride (BEA 1654). The compound had a Ki value of 32 nM (5-HT: 8 nM) on 5-HT1 but no or very weak affinity for 5-HT2, alpha 1- and alpha 2-adrenoceptor sites in rat cerebral cortex homogenates. Intracarotid infusions of BEA 1654 (0.1-1.0 mg X kg-1 X min-1) were nearly equieffective in untreated and treated (phentolamine plus ketanserin) pigs in redistributing carotid arterial blood towards the nutrient compartment (particularly the skin and ears) at the expense of shunting via arteriovenous anastomoses (AVAs). In view of the high and selective affinity of BEA 1654 to 5-HT1 binding sites, the similarity of pharmacological responses between 5-HT and BEA 1654, and the ineffectiveness of antagonists of 5-HT2 and alpha-adrenergic receptors to block the AVA constriction and arteriolar dilatation caused by both 5-HT and BEA 1654, we conclude that these effects are mediated by 5-HT1 receptors. The vast difference between the ratios of Ki values for 5-HT1 binding sites and of the pharmacologically effective doses of BEA 1654 and 5-HT suggests that either BEA 1654 may be a partial agonist of 5-HT1 receptors or, while the drug binds with both subsets of 5-HT1 receptors, it is only one type which mediates the pharmacological response.

Evidence for a specific effect of BHT 920, an azepine derivative, on tyrosine hydroxylase in the dopaminergic system of the rat.

The effect of BHT 920, a putative presynaptic dopamine receptor agonist, on tyrosine hydroxylase was investigated in rats. The activity of the high affinity (BH4) form of striatal tyrosine hydroxylase was investigated dose-dependent manner in rats treated with BHT 920. This effect was pronounced in the dopaminergic system and was not observed to the same extent in the adrenal medulla. In vitro, BHT 920 had no effect upon striatal tyrosine hydroxylase activity. BHT 920 also did not affect either striatal adenylate cyclase activity or the extent of its stimulation by dopamine. The results concerning tyrosine hydroxylase were complemented by measurements of dopamine and DOPA in the striatal and the limbic system. The reduction in DOPA accumulation and in the high affinity form of tyrosine hydroxylase activity elicited by BHT 920 could be blocked by haloperidol, suggesting that BHT 920 may interact with the D2 dopamine receptor although a functional antagonism could not be ruled out. The present results suggest that BHT 920 may exert a specific effect upon tyrosine hydroxylase in dopaminergic nervous tissue which is not mediated by alpha 2-adrenoceptors.

Pramipexole binding and activation of cloned and expressed dopamine D2, D3 and D4 receptors.

Pramipexole (SND 919; 2-amino-4,5,6,7-tetrahydro-6-propylamino-benzthiazole-dihydrochlor ide) is a potent dopamine autoreceptor agonist. We have carried out an analysis of the binding affinities of dopamine D2L, D2S, D3, and D4 receptors for pramipexole using both [3H]pramipexole and [3H]spiperone as radioligands at cloned and heterologously expressed receptors. Studies were carried out using rat and human D2L, D2S and D3 receptors with equivalent results. When the binding of pramipexole to the high affinity, guanine nucleotide-sensitive state of each receptor was analyzed, pramipexole is most selective for D3 compared to D2 and D4 receptors. These results indicate a 5-fold selectivity of pramipexole for D3 receptors, while quinpirole and bromocriptine are non-selective or more D2/D4 receptor selective. Two measurements of receptor activation for dopamine D2, D3, and D4 receptors also show that pramipexole is most potent for activation of D3 receptors. The dopamine D3 receptor selectivity of pramipexole may explain the previously described properties of this drug, including its potent autoreceptor preference.

Interactions of MEN 935 (adimolol), a long acting beta- and alpha-adrenolytic antihypertensive agent, with postsynaptic alpha-adrenoceptors in different isolated blood vessels--influence of angiotensin II.

MEN 935 [1-(3-[3-(1-naphthoxy)-2-hydroxypropyl) amino)-3,3-dimethylpropyl)-2-benzimidazolinone-hydrochloride monohydrate, adimolol] is a long acting antihypertensive agent with beta- and alpha-adrenolytic properties. Preliminary experiments in pithed rats had led to the suggestion that the alpha-adrenolytic activity was of the alpha 2-subtype. The alpha-adrenolytic properties of MEN 935 were now tested in isolated vascular preparations of rat aorta, rabbit vena ischiadica and rabbit vena cava inferior against the selective alpha 1-adrenergic agonist phenylephrine (PE) and the selective alpha 2-adrenergic agonist B-HT 920 [2-amino-6-allyl-5,6,7,8-tetrahydro-4H-thiazolo-(4,5-d)azepine]. The experiments were performed in absence and in presence of 5 X 10(-9) mol/l angiotensin II (A II). MEN 935 antagonized contractions to phenylephrine as well as those to B-HT 920 in each vessel. A twofold shift to the right of the concentration-response curves to both agonists was obtained with concentrations between 1.9 X 10(-8) and 1.4 X 10(-5) mol/l, depending on the vessel under investigation. A II modulated the adrenolytic properties of MEN 935 in each vessel. However, irrespective of the presence or absence of A II, no pharmacologically relevant difference between antagonism against PE or B-HT 920 could be seen. In isolated vessels, MEN 935 exerts a nonselective alpha-adrenergic antagonism. In receptor binding studies in rat cerebellar cortex, MEN 935 showed a Ki of 5.2 X 10(-7) mol/l at alpha 1-adrenoceptors and a Ki of 1.3 X 10(-5) mol/l at alpha 2-adrenoceptors.(ABSTRACT TRUNCATED AT 250 WORDS)

[Pharmacokinetics of AR-L 115 BS in rhesus monkeys (author's transl)]. / Pharmakokinetische Untersuchungen mit AR-L 115 BS an Rhesusaffen.

Pharmacokinetic studies of the cardiotonic agent 2-[(2-methoxy-4-methylsulfinyl)phenyl]-1H-imidazo[4,5-b]pyridine (AR-L 115 BS) in rhesus monkeys following oral and intravenous administration of the 14C-labelled compound were performed. 1. Following oral administration the blood- and plasma level maximum was reached between 1 and 3 h with an average maximum concentration of 8% (whole blood) and 4% (plasma) of the administered dose. 3 h after reaching the maximum concentration the blood and plasma level had fallen to half the maximum concentration. The substance was absorbed completely. 2. Following i.v. injection the elimination of radioactivity from blood and plasma, resp., showed a two-phase course with elimination half-lives of t1/2 alpha = 75 min and t1/2 beta = 12 h. 3. Within 120 h following oral and i.v. administration, 95% and 91%, resp., of the administered radioactivity were excreted. Following both ways of administration a relatively rapid renal excretion occurred. 4. The distribution pattern of the urine metabolites showed a complete biotransformation of the initial compound. In all urinary fractions two main metabolites occurred. Because of the identical metabolite pattern a different metabolic behaviour following oral and i.v. administration can be excluded.

Synthesis and dopamine receptor binding studies of homochiral 8-aminopyrido[1,2-a]indoles.

Starting from L-aspartic acid the preparation of 8-aminopyrido[1,2-a]indole derivatives as benzo-fused analogs of the dopamine autoreceptor agonist 1 is reported. The key step of the synthesis is the Tf2O induced cyclization of the 1,2-amino alcohol 6. Receptor binding studies indicated selective affinity for the D-2 autoreceptor. Among the tested compounds, the dipropylamino derivative 2 showed the highest affinity for the D-2 receptor labelled with the selective autoreceptor agonist pramipexole (IC50 value: 450 nM). Thus, 2 is 15 times less potent than the aminoindolizine 1.

Inhibition of [3H]clonidine binding to rat brain alpha-adrenoceptors by imidazolidines. Correlation of binding potency and hypotensive activity.

The inhibition of specifically bound [3H]clonidine (spec. activity 26.7 Ci/mmol; final concentration 0.4 nmol/l) to rat brain membranes was determined for clonidine (2-[2,6-dichlorophenylimino]-2-imidazolidine hydrochloride, Catapresan) and a series of 28 congeneric imidazolidines with different substituents attached to the phenyl moiety and to the bridge nitrogen. The affinity of the compounds for the binding sites labelled by [3H]clonidine greatly depended on these substituents. The potencies of the substances in vitro to inhibit [3H]clonidine binding were correlated with reported hypotensive activities in vivo obtained in anaesthetized rabbits and normotensive rats. Correlation coefficients of r = 0.92 and of r = 0.83, resp., resulted which could be improved upon inclusion of lipophilicity omitting substances with logarithms of octanol/buffer partition coefficient less than -0.5. This finding was explained by the difference in accessibility to the central alpha-adrenoceptor binding sites in vitro and in vivo. Whereas no penetration barrier of importance will affect the process of in vitro binding, the blood/brain barrier has to be crossed before a hypotensive effect can be initiated. The binding affinities of the imidazolidines for central sites identified by [3H]clonidine may provide an indication for potential blood pressure lowering efficacy.

Synthesis, pharmacological investigation and computational studies on a tricyclic ergoline analog with selective dopamine autoreceptor activity.

The novel aminobenzindolone 8 was prepared and evaluated as a potential antipsychotic agent. The target compound was synthesized in eight steps starting from the tetrahydrobenzindolone 9. The key step of the synthesis was an electrophilic amination of the aromatic ketone 11 followed by reductive degradation when the diethoxymethyl group was employed for protection of the lactam nitrogen and also for the benzylic position 2a. Dopamine and serotonin receptor binding studies revealed 8 to be a potent and selective ligand at the D-2 autoreceptor (ki = 4.0 nM). Further in vivo studies including the GBL-test and locomotor activity measurements indicated agonistic activity of 8 at the prejunctional binding sites. Comparison of ab initio based molecular electrostatic isopotential maps corroborates our hypothesis that the dopamine structure 6, containing an intramolecular hydrogen bond donating effect of the meta-HO-group, represents the conformation which is active at the dopamine D-2 autoreceptor.

Blood level, distribution, excretion, and metabolite pattern of [14C]-brotizolam in the rat, dog, and rhesus monkey.

Following oral and intravenous administration the absorption, distribution, metabolite pattern and excretion of 14C-labeled brotizolam (2-bromo-4-(2-chlorophenyl)-9-methyl-6H-thieno[3,2-f]-1,2,4-triazolo [4,3-a]-1,4-diazepine, We 941, Lendormin), a new hypnotic, was studied in rats, dogs, and rhesus monkeys. Given orally to these species, [14C]-brotizolam was rapidly and extensively absorbed. The distribution of the radiolabeled drug was very fast indicated by blood level curves as well as by rat whole body autoradiography. [14C]-Brotizolam and its metabolites crossed the placenta; they also occurred in the milk of rats. In all species studied radioactivity was eliminated from blood with very similar half-lives ranging from 14.8 to 20.8 h. The renal portion of the total radioactivity elimination increased from 5.5% of the dose given to rats to 33.5% in rhesus monkeys and to 51.4% in dogs. Total excretion was complete 3 to 4 days after [14C]-brotizolam administration. Biliary excretion also occurred. In the species studied thin layer chromatographic separation of the biliarily and renally excreted radioactivity indicated a similar but not the same pattern of 2 to 3 major metabolites which were mostly totally conjugated. Unchanged [14C]-brotizolam was only excreted in minor quantities, if at all.

Biochemical studies with the new thienotriazolo-diazepine brotizolam.

Brotizolam (2-bromo-4-(2-chlorophenyl)-9-methyl-6H-thieno[3,2-f]-1,2,4-triazolo [4,3-a]-1,4-diazepine, We 941, Lendormin) is a newly developed thienotriazolo-diazepine with distinct hypnotic effects. It was biochemically characterized by performing various receptor binding studies, uptake and release studies in vitro and determining homovanillic acid brain concentrations in vivo. Using [3H]-flunitrazepam as a radioligand, brotizolam showed an extremely high affinity for specific benzodiazepine binding sites in the rat brain, demonstrated by an IC50 value of 1.0 nmol/l. Using both [3H]-flunitrazepam and [3H]-brotizolam as radioligands, a strong correlation between the IC50 values of brotizolam and various benzodiazepines could be shown. [3H]-Flunitrazepam as well as [3H]-brotizolam bound with similar affinities to cerebellar and hippocampal synaptosomal membranes. In contrast to [3H]-flunitrazepam binding, however, [3H]-brotizolam had twice the number of specific binding sites in the hippocampus. According to the maximum binding of [3H]-flunitrazepam, the inhibition curve of brotizolam also increased in the presence of 10(-4) mol/l gamma-aminobutyric acid and decreased remarkably in the presence of 10(-4) mol/l bicuculline. Using [3H]-muscimol as a ligand, a modulating effect of brotizolam could be shown by increasing the low affinity with no change in the number of binding sites. From various further receptor binding studies, as well as from in vitro uptake and release studies of [3H]-noradrenaline, [3H]-serotonin and [3H]-dopamine, no indication was found of another biochemical effect of brotizolam. There was also no change in the homovanillic acid concentration in the rat brain striata in vivo after brotizolam treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

Biochemical pharmacology of pirenzepine. Similarities with tricyclic antidepressants in antimuscarinic effects only.

5,11-Dihydro-11-[(4-methyl-1-piperazinyl) acetyl]-6H-pyrido[2,3-b][-1,4]-benzodiazepin-6-one dihydrochloride (pirenzepine, Gastrozepin) and some tricyclic antidepressant drugs which show a very close relationship concerning the chemical structure were investigated in numerous binding, uptake and enzymatic studies in vitro. With pirenzepine a high affinity binding could be demonstrated only to muscarinic receptors (Ki = 58 nmol/l). In all other studies pirenzepine had a very weak or no effect at all. In contrast, tricyclic antidepressants bound with high but different affinities to various receptors as known from numerous publications. The highest affinities were found with imipramine at the specific imipramine binding sites (Ki = 9.8 nmol/l) and at the alpha 1-receptor (Ki = 39 nmol/l), with desipramine at the muscarinic receptors (Ki = 88 nmol/l), with mianserin at the H1-(Ki = 3.4 nmol/l) and 5HT2-receptors (Ki = 7.3 nmol/l). Moreover, imipramine and desipramine showed their known substantial inhibition of noradrenaline and/or 5-hydroxytryptamine uptake. Thus, a homogeneous affinity or activity profile of the antidepressants studied does not exist. The only common property of pirenzepine and the tricyclic antidepressants was found to be the high affinity binding to the muscarinic receptors which might explain the common antisecretory action of these agents. Because of the unique specificity of pirenzepine lacking all other effects of the tricyclic antidepressants as demonstrated in this study, it is very unlikely that this drug exerts any antidepressant-like central action.

Tricyclic azaergoline analogues: synthesis, structural modifications, and pharmacological studies.

As an extension of previous investigations on synthesis and dopamine autoreceptor activity of bicyclic ergoline analogues the tricyclic azaergoline analogues 9a and 9b were synthesized. Furthermore, the geometry of the aromatic beta-ethylamine moiety of 9a,b was modified by stereoselective construction of the cycloheptenyl fused pyrazolopyridine derivative 7 and the aminomethyl substituted tricycle 10. Binding affinity of these compounds at dopamine (DA) receptor sites was investigated employing rat striatum homogenate: The compounds reveal modest to weak, but selective binding to a dopamine D-2 receptor when it is labelled with the DA-autoreceptor agonist [3H]-SND 919. In vivo studies with mice showed that 7, 9a,b, and 10 affect their CNS activity.

In vitro and in vivo studies of the non-sedating antihistamine epinastine.

Epinastine (3-amino-9,13b-dihydro-1H-dibenz [c,f]imidazo[1,5-a]azepine hydrochloride, WAL 801 CL) was tested in vitro and in vivo in comparison with other H1-receptor antagonists. In the guinea pig ileum and in receptor binding studies the test substance showed a high affinity to H1-receptors. The following rank order was determined: WAL 801 CL greater than astemizole greater than terfenadine. These results were confirmed in vivo. The studies were carried out with oral and intravenous administration of WAL 801 CL to assess the inhibition of histamine-induced reactions in the skin or the lung of rats, dogs and guinea pigs. 10- to 100fold antihistaminic doses of WAL 801 CL showed no effect on the sleeping-waking behaviour of cats. From this and other results it is suggested that the compound does not penetrate in the central nervous system. The action pattern of WAL 801 CL as a non-sedating antihistamine corresponds more to that of terfenadine than that of ketotifen.

In vivo role of the adenosine A3 receptor: N6-2-(4-aminophenyl)ethyladenosine induces bronchospasm in BDE rats by a neurally mediated mechanism involving cells resembling mast cells.

Activation of the adenosine A3 receptor subtype by the agonist N6-2-(4-aminophenyl)ethyladenosine is shown here to induce bronchospasm (increased pulmonary resistance and decreased pulmonary compliance) in BDE strain rats. The effect is substantially reduced by pretreating the rats with compound 48/80, disodium cromoglycate (30 micrograms/kg) or epinastine (10 micrograms/kg), which is compatible with involvement of mast cells. It is also substantially reduced by combined vagotomy and atropinization or by pretreatment with the NK2 receptor antagonist L-659,877, suggesting involvement of neuropeptide-mediated neural pathways. The mechanism by which activation of the adenosine A3 receptor induces bronchospasm is distinct from the mechanism by which activation of the adenosine A1 receptor induces bronchospasm. In particular, the A1 agonist 2-chloro-N6-cyclopentyladenosine can increase pulmonary resistance independently of mast cell activation. These results are in accord with the concept that a pathway exists in vivo by which activation of mast-like cells can activate axon reflexes, that adenosine acting through its A3 receptor can potentially up-regulate this pathway and that antiallergic substances such as disodium cromoglycate and epinastine may interfere with this pathway.