Cannabinoid receptors and their endogenous agonists

Marijuana has been in use for over 4000 years as a therapeutic and as a recreational drug. Within the past decade, two cannabinoid receptor types have been identified, their signal transduction characterized, and an endogenous lipid agonist isolated from mammalian tissues. The CB1 cannabinoid receptor is widely distributed in mammalian tissues, with the highest concentrations found in brain neurons. CB1 receptors are coupled to modulation of adenylate cyclase and ion channels. The CB2 receptor is found in cells of the immune system and is coupled to inhibition of adenylate cyclase. Both receptor types selectively bind delta 9-THC, the active principle in marijuana, and anandamide (arachidonylethanolamide), an endogenous cannabimimetic eicosanoid. Progress is being made in the development of novel agonists and antagonists with receptor subtype selectivity, mice with genetic deletion of the cannabinoid receptors, and receptor-specific antibodies, which should help in providing a better understanding of the physiological role of the cannabinoid receptors.

Diffraction of a gaussian beam around a strip mask

A theoretical treatment is given for the diffraction of a Gaussianbeam around an opaque strip mask. Such situations arise frequentlyin the diffraction of laser beams around wires and fibers. Scalarderivations are given for the Fraunhofer and Fresnel regions with bothdevelopments, leading to similar forms of rapidly convergent series forthe field at an observation plane. Predictions show good agreementwith measurements on the diffraction patterns from wires.

LY320135, a novel cannabinoid CB1 receptor antagonist, unmasks coupling of the CB1 receptor to stimulation of cAMP accumulation

LY320135 is a selective antagonist for the brain CB1 receptor, having greater than 70-fold higher affinity for the CB1 than the peripheral CB2 receptor. The Ki values for LY320135 at the CB1 and CB2 receptors, transfected and stably expressed in cell lines, were 224 nM and > 10 microM, respectively. Similar Ki values were measured in binding studies performed on cerebellum and spleen membrane preparations endogenously expressing the CB1 (203 nM) and CB2 (> 10 microM) receptors, respectively. LY320135 functionally reversed anandamide-mediated adenylate cyclase inhibition in Chinese hamster ovary (CHO) cells stably expressing the CB1 receptor. Pertussis toxin treatment of CHO cells expressing the CB1 receptor attenuated the anandamide-mediated inhibition of adenylate cyclase and unmasked a stimulatory effect of anandamide on adenylate cyclase. The stimulatory component was blocked with LY320135. This compound also blocked WIN 55212-2-mediated inhibition of N-type calcium channels and activation of inwardly rectifying potassium channels in N18 and AtT-20-CB2 cells, respectively. LY320135 is a promising lead compound for the further development of novel, potent and selective cannabinoid antagonists of novel structure.

Differential regulation of C-C chemokines during fibroblast-monocyte interactions: adhesion vs. inflammatory cytokine pathways

The cell-to-cell interactions during chronic inflammatory diseases likely contribute to leukocyte accumulation leading to increased pathology and organ dysfunction. In particular, there is a paucity of information relating to the maintenance of chronic fibrotic diseases. Using a lung fibroblast line and enriched monocyte populations, we have investigated the activational events which contribute to the production of two C-C chemokines, macrophage inflammatory protein-1 alpha (MIP-1alpha) and monocyte chemoattractant protein-1 (MCP-1), during fibroblast-monocyte interactions. Neither the fibroblast cell line (16lu) nor isolated monocytes alone produced significant levels of MIP-1alpha or MCP-1. However, when isolated monocytes were layered onto 16 lu fibroblast monolayers a significant increase in MIP-1alpha and MCP-1 production was observed. The use of fixed cell populations indicated that the MIP-1alpha was derived from monocytes and MCP-1 from both cell populations. To examine the molecules which were required for chemokine production during the interaction, specific antibodies were used in the co-cultures. Blocking beta3-integrin interactions significantly inhibited MIP-1alpha production. In contrast, beta-integrin interactions had no effect on the MCP-1 production, while, neutralization of TNF significantly decreased MCP-1 production during the co-culture. These data indicate that fibroblast-monocyte interactions induce chemokine production through different mechanisms and a combination of these responses may contribute to the maintenance of the mononuclear cell accumulation during disease progression.

Concurrent stimulation of cannabinoid CB1 and dopamine D2 receptors augments cAMP accumulation in striatal neurons: evidence for a Gs linkage to the CB1 receptor

Cannabinoids act at the CB1 receptor to inhibit adenylate cyclase activity via a pertussis toxin-sensitive G-protein. Within the striatum, CB1 receptors have been shown to be localized on the same neurons as Gi-coupled dopamine D2 receptors. In this study we have examined the interactions of CB1 and D2 receptors on adenylate cyclase. In striatal neurons in primary culture, both the CB1 receptor agonist [3-(1, 1-dimethylheptyl)-11-hydroxy-Delta8tetrahydrocannabinol] (HU210) and the D2 receptor agonist quinpirole inhibited forskolin-stimulated cAMP accumulation when applied separately. In contrast, HU210 and quinpirole in combination augmented cAMP accumulation. This augmentation was blocked by the CB1 receptor antagonist SR141716A or the D2 antagonist sulpride. Pertussis toxin treatment of striatal neurons prevented the inhibition of cAMP accumulation by D2 receptors but unmasked a cannabinoid receptor-mediated stimulatory effect on cAMP accumulation. The cannabinoid receptor-stimulated accumulation of cAMP was blocked in a concentration-dependent manner by SR141716A, suggesting that the response was regulated through the CB1 receptor. Similar augmentation of cAMP accumulation after pertussis toxin treatment was observed in Chinese hamster ovary (CHO) cells transfected with, and stably expressing, the CB1 receptor. This stimulation of cAMP was not Ca2+-sensitive and was unaffected by a range of protein kinase inhibitors. Treatment of the pertussis toxin-treated cells with cholera toxin before CB1 receptor activation amplified the stimulatory pathway, suggesting that this response was mediated through a Gs-type G-protein. Stimulation of cAMP accumulation was not observed after pertussis toxin treatment of CHO cells expressing the human CB2 receptor, suggesting that this novel signaling pathway is unique to the cannabinoid CB1 receptor.

Zafirlukast for symptomatic mild-to-moderate asthma: a 13-week multicenter study. The Zafirlukast Trialists Group

The efficacy of the oral leukotriene-receptor antagonist zafirlukast was assessed as maintenance therapy for patients with mild-to-moderate asthma. A total of 762 patients aged 12 to 76 years were enrolled in a 13-week, multicenter, double-masked, placebo-controlled, parallel-group trial and randomly assigned to receive either zafirlukast (20 mg twice daily) or placebo. Patients were maintained on as-needed beta-agonist therapy throughout the study and had to have a cumulative daytime asthma symptoms score > or = 8 (on a daily scale of 0 to 3) over 7 consecutive days before randomization. Efficacy was assessed by changes in symptoms, beta-agonist use, and pulmonary function. Safety was assessed by adverse experiences, laboratory test results, physical examination, and electrocardiography. Zafirlukast significantly decreased daytime asthma symptoms scores (-26.5%), nighttime awakenings (-19.8%), mornings with asthma (-29.0%), and beta-agonist use (-22.3%) and significantly increased morning peak expiratory flow rate (6.9%) and forced expiratory volume in 1 second (6.3%) compared with placebo. Changes in symptoms, beta-agonist use, and pulmonary function occurred within 2 days of zafirlukast treatment and continued throughout the trial. Zafirlukast was well tolerated. Pharyngitis and headache were the most common adverse events, occurring with similar frequency in both the zafirlukast and placebo groups. No clinically significant changes were observed in laboratory test results, findings on physical examination, or electrocardiographic findings. We conclude that zafirlukast produces early and sustained effects in the treatment of mild-to-moderate asthma.

Cannabinoid receptors in the human brain: a detailed anatomical and quantitative autoradiographic study in the fetal, neonatal and adult human brain

The anatomical distribution and density of cannabinoid receptors in the human brain was studied in one fetal (33 weeks gestation), two neonatal (aged three to six months) and eight adult (aged 21-81 years) human cases using quantitative receptor autoradiography following in vitro labelling of sections with the synthetic cannabinoid agonist [3H]CP55,940. Cannabinoid receptors were distributed in a heterogeneous fashion throughout the adult human brain and spinal cord. The allocortex contained very high concentrations of cannabinoid receptor binding sites in the dentate gyrus, Ammons's horn and subiculum of the hippocampal formation; high concentrations of receptors were also present in the entorhinal cortex and amygdaloid complex. Cannabinoid receptor binding sites were also present throughout all regions of the neocortex, where they showed a marked variation in density between the primary, secondary and associational cortical regions: the greatest densities of receptors were present in the associational cortical regions of the frontal and limbic lobes, with moderate densities in the secondary sensory and motor cortical regions, and with the lowest densities of receptors in the primary sensory and motor cortical regions. Relatively high concentrations of cannabinoid receptors were consistently seen in cortical regions of the left (dominant) hemisphere, known to be associated with verbal language functions. In all of the cortical regions, the pattern and density of receptor labelling followed the neocortical laminar organization, with the greatest density of receptors localized in two discrete bands--a clearly delineated narrow superficial band which coincided with lamina I and a deeper broader, conspicuous band of labelling which corresponded to laminae V and VI. Labelling in the intervening cortical laminae (II-IV) showed lower densities, with a well delineated narrow band of label in the middle of laminae IV in the associational cortical regions. The thalamus showed a distinctive heterogeneous distribution of cannabinoid receptors, with the highest concentration of receptors localized in the mediodorsal nucleus, anterior nuclear complex, and in the midline and intralaminar complex of nuclei, i.e. in thalamic nuclei which have connectional affiliations with the associational cortical areas. The basal ganglia showed a distinctive heterogeneous pattern of receptor binding, with the very highest concentrations in the globus pallidus internus, moderate concentrations in the globus pallidus externus and ventral pallidum, and moderately low levels of binding throughout the striatal complex. In the midbrain, some of the highest levels of cannabinoid receptor binding sites in the human brain were present in the substantia nigra pars reticulata, with very low levels of labelling in all other midbrain areas. The highest densities of cannabinoid receptor binding in the hindbrain were localized in the molecular layer of the cerebellar cortex and the dorsal motor nucleus of the vagus, with moderate densities of receptors in the nucleus of the solitary tract. The spinal cord showed very low levels of receptor binding. Studies on the distribution of cannabinoid receptors in the fetal and neonatal human brain showed similar patterns of receptor distribution to that observed in the adult human brain, except that the density of receptor binding was generally markedly higher, especially in the basal ganglia and substantia nigra. The pattern of cannabinoid receptor labelling in the striatum showed a striking patchy pattern of organization which was especially conspicuous in the fetal brain. These results show that cannabinoid receptor binding sites in the human brain are localized mainly in: forebrain areas associated with higher cognitive functions; forebrain, midbrain and hindbrain areas associated with the control of movement; and in hindbrain areas associated with the control of motor and sensory functions of the autonomic nervous system. (AB

Simultaneous multianalyte nucleic acid detection for gastrointestinal bacterial pathogens using GeneSTAR technology

The use of Gene-based simultaneous target amplification and recognition (GeneSTAR) technologies allows for the rapid detection of five different bacterial gastrointestinal pathogens from stool sample. The process involves DNA isolation, multianalyte polymerase chain reaction (PCR) amplification and single base mismatch detection in a microtiter plate format. The analysis is instrument compatible and can be completed in less than five hours.

Inhibition of interleukin-8 reduces tumorigenesis of human non-small cell lung cancer in SCID mice

The salient feature of solid tumor growth is the strict dependence on local angiogenesis. We have previously demonstrated that IL-8 is an angiogenic factor present in freshly isolated specimens of human non-small cell lung cancer (NSCLC). Using a model of human NSCLC tumorigenesis in SCID mice, we now report that IL-8 acts as a promoter of human NSCLC tumor growth through its angiogenic properties. Passive immunization with neutralizing antibodies to IL-8 resulted in more than 40% reduction in tumor size and was associated with a decline in tumor-associated vascular density and angiogenic activity. IL-8 did not act as an autocrine growth factor for NSCLC proliferation. The reduction in primary tumor size in response to neutralizing antibodies to IL-8 was also accompanied by a trend toward a decrease in spontaneous metastasis to the lung. These data support the notion that IL-8 plays a significant role in mediating angiogenic activity during tumorigenesis of human NSCLC, thereby offering a potential target for immunotherapy against solid tumors.

Guidelines for the retention, storage, and use of residual dried blood spot samples after newborn screening analysis: statement of the Council of Regional Networks for Genetic Services

These guidelines provide scientific information for policy development by state health departments considering appropriate use of newborn screening specimens after screening tests are finished. Information was collected, debated, and formulated into a policy statement by the Newborn Screening Committee of the Council of Regional Networks for Genetic Services (CORN), a federally funded national consortium of representatives from 10 regional genetics networks. Newborn screening programs vary widely in approaches and policies concerning residual dried blood spot samples (DBS) collected for newborn screening. Recognition of the epidemiological utility of DBS samples for HIV seroprevalence surveys and a growing interest in DBSs for DNA analysis has intensified consideration of issues regarding retention, storage, and use of residual DBS samples. Potentially these samples provide a genetic material "bank" for all newborns nationwide. Their values as a resource for other uses has already been recognized by scientists, administrators, and judicial officials. Programs should promulgate rules for retention and use of residual newborn screening DBS samples based on scientifically valid information. Banking of newborn samples as sources of genetic material should be considered in light of potential benefit or harm to society.

Fresnel diffraction from curved fiber snippets with application to fiber diameter measurement

Fiber curvature is examined for its effect on apparent measured fiber diameter in a double-diffraction-based instrument that is in widespread use in the wool industry. The development uses a two-dimensional Fresnel diffraction model. The magnitude of the effect is studied for 2-mm-long snippets of various diameters from 8 to 50 µm and with radii of curvature of 1 m (straight), 600 µm, 280 µm, 200 µm, and 160 µm. The two-dimensional Fresnel model gives rise to deeply nested vector integrations that make computations with a straightforward approach exceedingly time consuming and impractical. A number of simplifying techniques are used to facilitate and speed up the numerical computations, thereby permitting investigations to be carried out on a personal computer.

Loss of A1 adenosine receptors in human temporal lobe epilepsy

Using quantitative receptor autoradiographic methods we have examined A1 adenosine receptors, adenosine uptake sites, benzodiazepine receptors, NMDA, AMPA, and kainic acid receptors in temporal lobes removed from patients suffering from complex partial seizures and in normal control post-mortem temporal cortex. Binding to A1 adenosine receptors and NMDA receptors was reduced in epileptic temporal cortex, while the other neurochemical parameters were unchanged. The reason for this A1 receptor loss is unclear as it occurred in both idiopathic and symptomatic cases and thus may be a consequence rather than an initial cause of seizures. However, because adenosine is a powerful anticonvulsant substance, loss of anticonvulsant A1 receptors may contribute to the human epileptic condition. It is also possible that the observed differences in A1 binding are due to autopsy vs. biopsy changes in the levels of A1 adenosine receptors.

Localisation of the adenosine uptake site in the human brain: a comparison with the distribution of adenosine A1 receptors

Using quantitative receptor autoradiography we investigated the distribution of the adenosine uptake site labelled with [3H]NBTI in post-mortem human brain and compared its distribution with that of the A1 adenosine receptor labelled with [3H]CHA. The highest levels of [3H]NBTI binding were found in the cortex and striatum, with moderate levels in the hippocampus, globus pallidus, cerebellum and some midbrain and spinal cord nuclei. The distribution of A1 receptors and this adenosine uptake site differed in the hippocampus where A1 receptors were highest in CA1 but the uptake site was low in CA1 and higher in the molecular layer of the dentate gyrus. These results define the anatomical distribution of the high affinity NBTI sensitive adenosine uptake site in the normal human brain.

Neurochemical and morphological changes associated with human epilepsy

To date a multitude of studies into the morphology and neurochemistry of human epilepsy have been undertaken with variable, and often inconsistent, results. This review summarises these studies on a range of neurotransmitters, neuromodulators, neuropeptides and their receptors. In addition to this, novel changes in cell viability and sprouting have been identified and are discussed. Whether the alterations observed are a result of the seizures or are a contributory factor is unclear. However, it may be that following an initial insult (such as febrile convulsions, status epilepticus or head injury) secondary processes occur both of an anticonvulsant nature in an attempt to compensate for seizure activity, and in a kindling type of fashion, resulting in an increased susceptibility to seizures, leading to future seizures. Many of the alterations documented in this study probably represent one or both of these processes. Clearly no single chemical abnormality or morphological alteration is going to explain the clinically diverse disorder of epilepsy. However, by drawing together the neurochemistry and morphology of epilepsy, we may begin to understand the mechanisms involved in seizure disorders.

The leukotriene D4-receptor antagonist, ICI 204,219, relieves symptoms of acute seasonal allergic rhinitis

The efficacy and safety of single oral doses of the leukotriene D4-receptor antagonist, ICI 204,219, were tested in subjects with acute seasonal allergic rhinitis. Subjects who were enrolled in the double-blind, placebo-controlled trial spent 8 h/d for two consecutive days in a park at the peak of ragweed season (counts > 1,000 grains/m3). Subjects (n = 164) who had sufficient symptoms during a 3-h baseline period on Day 1 were randomized to treatment with 10 (n = 33), 20 (n = 33), 40 (n = 33), or 100 mg (n = 32) of ICI 204,219 or placebo (n = 33). Rhinitis symptoms (nasal congestion, sneezing, rhinorrhea, itchy nose, throat and palate, and eye symptoms) were recorded hourly in the park and three times each evening at home. Blood samples were collected twice daily to determine plasma levels of ICI 204,219. Nasal congestion improved (p < 0.01) most consistently from the evening of Day 1 through Day 2 after treatment with 20- and 40-mg doses of ICI 204,219 versus placebo. Sneezing and rhinorrhea (p < or = 0.05) also improved on Day 2 for subjects who received 20- and 40-mg doses of ICI 204,219 compared with placebo. Mean symptoms scores for the entire day showed that 20 mg of ICI 204,219 was the minimally effective dose in this trial. The onset of action for all treatment groups, including placebo, was within the first 2 h of dosing. No serious adverse events were reported during the trial. ICI 204,219 was well tolerated and relieved symptoms of acute seasonal allergic rhinitis.

Induction of the Krox 24 transcription factor in striosomes by a cannabinoid agonist

The striatum is composed of two compartments arranged as a mosaic, the striosomes (patches) and the matrix, which differ in their neurochemical and neuroanatomical properties. Along with a large number of neurotransmitter-related differences, these regions have recently been shown to differ in their immediate early gene (IEG) response to indirect dopamine agonists. Both Fos and Krox 24 can be preferentially induced in the striosomal compartment of the striatum by amphetamine. This compartmentalization of response suggests that there are functionally distinct molecular signalling pathways in striosomes and matrix. This paper examines the response of Krox 24 to i.p. administration of the cannabinoid agonist CP55,940 and demonstrates a selective induction of this protein within the striosomes 2 h after drug administration. This result suggests that cannabinoid receptors may regulate striatal gene expression.

c-fos antisense reduces expression of Krox 24 in rat caudate and neocortex

1. The aim of this study was to investigate the neurochemical effects and measure the anatomical spread of infusion of c-fos antisense (AS) DNA into the striatum. 2. Rats were anesthetized and infused in opposing striata with c-fos AS and c-fos sense (S) DNA. Ten hours later they were injected with apomorphine (2 mg/kg, i.p.) and 20 min later they were overdosed with sodium pentobarbital and their brains either perfused or frozen. Vibratome-cut sections were immunostained for the detection of c-fos, JunB, Krox 24, somatostatin, substance P, dynorphin, tyrosine hydroxylase, and enkephalin. Cryostat-cut sections from the caudate were immunostained for the detection of c-fos, JunB, and Krox 24, as well as in situ hybridization for proenkephalin mRNA. Sections from the globus pallidus were used for the autoradiographic localization of D2 dopamine and A2a adenosine receptors. Sections from the substantia nigra were used for the autoradiographic localization of D1 dopamine and cannabinoid receptors. A second group of rats were injected in opposing striata with biotin-labeled c-fos AS DNA and c-fos S DNA. Ten hours later they were challenged with apomorphine (2 mg/kg, i.p.) and 20 min later brains were either perfused or frozen. Sections from these brains were cut throughout the rostral-caudal extent of the forebrain and the biotin labeled AS DNA was localized. 3. Krox 24 was expressed at high levels on the sense side of the brain in the striatum and overlying neocortex. However, on the AS-injected side there was a reduction in Krox 24 expression in striatum and overlying cortex. The biotin-labeled AS studies confirmed that the striatal infusion spread throughout the dorsal striatum as well as the overlying neocortex. We did not detect any changes in neurotransmitter receptors, neuropeptides, or tyrosine hydroxylase in AS/S-injected rat brains. 4. These results demonstrate that c-fos AS reduces Krox 24 expression in striatal and neocortical neurons but does not change the expression of a number of other proteins involved in basal ganglia function. Whether this effect is due to nonspecific actions of c-fos AS or to its effects on a component of the transduction pathway responsible for basal Krox 24 expression (NMDA receptors?) is unknown.

Effects of 6 weeks of therapy with oral doses of ICI 204,219, a leukotriene D4 receptor antagonist, in subjects with bronchial asthma. ACCOLATE Asthma Trialists Group

The efficacy of 6 wk of therapy with oral ICI 204,219, a selective leukotriene D4 (LTD4) receptor antagonist, was evaluated in subjects with moderate asthma during a multicenter, double-blind, randomized, placebo-controlled, dose-ranging study. Subjects who entered the trial had been chronically treated for asthma with beta agonist alone or in combination with theophylline. Subjects were randomized to treatment with twice daily doses of ICI 204,219 (5, 10, or 20 mg) or placebo if they had an FEV1 between 40 and 75% of predicted values without bronchodilator therapy and a daytime asthma score > 10 (range 0 to 21 per wk) for 7 consecutive d. Efficacy was evaluated from the results of symptom assessments, pulmonary function tests, and rescue medication use. Of 276 subjects randomized to treatment, 266 (10 mg, n = 66; 20 mg, n = 67; 40 mg, n = 67; placebo, n = 66) were analyzed for efficacy. Diary card assessments showed that treatment with increasing doses of ICI 204,219 linearly improved five efficacy criteria without increasing the number or severity of adverse events. The 40 mg dose was more effective than placebo (p < 0.05) in reducing nighttime awakenings, first morning asthma symptoms, the daytime asthma score, and albuterol use and in increasing evening peak expiratory flow (PEF) rates as well as FEV1. Compared with baseline measurements, the 40 mg dose decreased awakenings by 46%, albuterol use by 30%, and daytime symptoms by 26% and increased FEV1 by 11%. ICI 204,219 improves objective and subjective measures of asthma severity in moderately ill asthmatic subjects and may provide a new treatment option for the disease.

Inhaled ICI 204,219 blocks antigen-induced bronchoconstriction in subjects with bronchial asthma

Three inhalation formulations of ICI 204,219 were compared for antagonism of antigen-induced bronchoconstriction in 16 subjects with asthma who demonstrated reproducible hypersensitivity to allergen during screening challenges. Each subject received a single 0.2-mg dose of each formulation and was challenged with ragweed 30 min after administration of ICI 204,219 until the forced expiratory volume in 1 s (FEV1) decreased by 20 percent or the maximum allergen concentration (100 micrograms/ml) was reached. The majority of subjects tolerated 100 micrograms/ml of allergen without a 20 percent decrease in FEV1. Inhalation formulations of ICI 204,219 successfully inhibited bronchoconstriction in subjects with reproducible sensitivity to ragweed challenges.

Inhibition of leukotriene D4-induced bronchoconstriction in subjects with asthma: a concentration-effect study of ICI 204,219

The peptide-leukotriene antagonist, ICI 204,219 [4-(5-cyclopentyloxycarbonylamino-lmethylindol-3-ylmethyl )-3-methoxy-n-o-tolylsulfonyl benzamide], was administered 12 hours before an inhaled leukotriene D4 (LTD4) challenge during a double-blind, placebo-controlled, randomized, two-period crossover trial. Subjects with mild asthma were randomized into five treatment groups (six subjects each) and received single oral doses of placebo and either 5, 10, 20, 40, or 100 mg of ICI 204,219 on day 1 of each treatment period. ICI 204,219 was tolerated well by all subjects. A progressive dose response was observed for doses of ICI 204,219 from 5 mg through 100 mg. Compared with placebo, ICI 204,219 increased the concentration (PC20FEV1) and dose of LTD4 needed to reduce forced expiratory volume in 1 second (FEV1) by 20%. Mean LTD4 PC20FEV1 for groups that received placebo and 10, 40, or 100 mg ICI 204,219 increased by tenfold or more (p < 0.05). An association was found between the plasma concentration and protective effect of ICI 204,219 (p < 0.01). ICI 204,219 is the first leukotriene receptor antagonist for which a relationship has been established between drug plasma levels and its protective effect in subjects with asthma.

Loss of cannabinoid receptors in the substantia nigra in Huntington's disease

Previous autoradiographic studies in rats using [3H]CP55,940 have demonstrated the cannabinoid receptor to be located on the axon terminals of striatal efferent neurons projecting to the globus pallidus and substantia nigra. Because these neurons are selectively lost in Huntington's disease, a loss of [3H]CP55,940 binding is predicted in the substantia nigra of the Huntington's disease brain. We have used autoradiography to compare the binding of [3H]CP55,940 in the substantia nigra of Huntington's disease and neurologically normal brains. The results have demonstrated that cannabinoid receptors in the normal human substantia nigra are discreetly localized within the substantia nigra pars reticulata. In contrast, the Huntington's disease brains show a massive loss (97.5%) of cannabinoid receptor binding in the substantia nigra pars reticulata. These results show that in the substantia nigra of the human brain cannabinoid receptors are located on striatonigral terminals which degenerate in Huntington's disease.

Effect of a synthetic leukocyte elastase inhibitor on thrombin-induced pulmonary edema in the rat

The effect of a synthetic leukocyte elastase inhibitor on thrombin-induced pulmonary edema was studied in rats. The chloromethylketone human neutrophil elastase inhibitor, ICI 200,355, blunted rat leukocyte elastase activity in rat lung tissue. Administration of thrombin produced a significant increase (p < .01) in lung weight. The wet weight to dry weight ratio (WW/DW) and relative water contents were also significantly elevated (p < .01). Pretreatment with ICI 200,355 (200 micrograms/kg h-1) resulted in significant reductions (p < .05) in lung weight and a tendency to decrease WW/DW and water content compared with animals given thrombin alone. It is possible that the elastase inhibitor effectively reduced the rate of thrombin-induced pulmonary edema by attenuation of increased vascular permeability.