5-HT6 receptor antagonists. Design, synthesis, and structure-activity relationship of substituted 2-(1-methyl-4-piperazinyl)pyridines

In this study, we present the discovery and pharmacological characterization of a new series of 6-piperazinyl-7-azaindoles. These compounds demonstrate potent antagonism and selectivity against the 5-HT6 receptor. Our research primarily focuses on optimizing the lead structure and investigating the structure-activity relationship (SAR) of these compounds. Our main objective is to improve their activity and selectivity against off-target receptors. Overall, our findings contribute to the advancement of novel compounds targeting the 5-HT6 receptor. Compound 29 exhibits significant promise in terms of pharmacological, physicochemical, and ADME (Absorption, Distribution, Metabolism, and Excretion) properties. Consequently, it merits thorough exploration as a potential drug candidate due to its favorable activity profile and successful outcomes in a range of in vivo experiments.

Purinergic Receptors in the Airways: Potential Therapeutic Targets for Asthma?

Extracellular ATP functions as a signaling messenger through its actions on purinergic receptors, and is known to be involved in numerous physiological and pathophysiological processes throughout the body, including in the lungs and airways. Consequently, purinergic receptors are considered to be promising therapeutic targets for many respiratory diseases, including asthma. This review explores how online bioinformatics resources combined with recently generated datasets can be utilized to investigate purinergic receptor gene expression in tissues and cell types of interest in respiratory disease to identify potential therapeutic targets, which can then be investigated further. These approaches show that different purinergic receptors are expressed at different levels in lung tissue, and that purinergic receptors tend to be expressed at higher levels in immune cells and at more moderate levels in airway structural cells. Notably, P2RX1, P2RX4, P2RX7, P2RY1, P2RY11, and P2RY14 were revealed as the most highly expressed purinergic receptors in lung tissue, therefore suggesting that these receptors have good potential as therapeutic targets for asthma and other respiratory diseases.

Application of the PET ligand [11C]ORM-13070 to examine receptor occupancy by the α2C-adrenoceptor antagonist ORM-12741: translational validation of target engagement in rat and human brain

Background

Availability of the α_2C-adrenoceptor (α_2C-AR) positron emission tomography (PET) tracer, [¹¹C]ORM-13070, and the α_2C-AR antagonist ORM-12741 allows probing of the roles of this G-protein coupled receptor subtype in brain function, both in healthy humans and in patients with various brain disorders. This translational study employed [¹¹C]ORM-13070 autoradiography and PET to determine α_2C-AR occupancy by ORM-12741 in rat and human brain, respectively.

Results

ORM-12741 has high affinity (K_i: 0.08 nM) and potent antagonist activity (K_b: 0.04 nM) as well as selectivity (K_i estimates for the human α_2A-AR and α_2B-AR were 8.3 nM and 0.8 nM, respectively) for the human α_2C-AR subtype. [¹¹C]ORM-13070 had highest uptake in the basal ganglia of rat and human brain. Pretreatment with ORM-12741 inhibited [¹¹C]ORM-13070 binding in rat striatum in a time- and dose-dependent manner at 10 and 50 µg/kg (s.c.) with an EC₅₀ estimate of 1.42 ng/mL in rat plasma, corresponding to protein-free drug concentration of 0.23 nM. In the living human brain, time- and dose-related α_2C-AR occupancy was detected with EC₅₀ estimates of 24 ng/mL and 31 ng/mL for the caudate nucleus and putamen, respectively, corresponding to protein-free concentrations in plasma of 0.07 nM and 0.1 nM. Modelling-based maximum α_2C-AR occupancy estimates were 63% and 52% in the caudate nucleus and the putamen, respectively.

Conclusions

ORM-12741 is a selective α_2C-AR antagonist which penetrates the rat and human brain to occupy α_2C-ARs in a manner consistent with its receptor pharmacology.

Trialregistrationnumberanddateofregistration: ClinicalTrial.cov NCT00829907. Registered 11 December 2008. https://clinicaltrials.gov/.

GABAB receptor positive allosteric modulators with different efficacies affect neuroadaptation to and self-administration of alcohol and cocaine

Drugs of abuse induce widespread synaptic adaptations in the mesolimbic dopamine (DA) neurons. Such drug-induced neuroadaptations may constitute an initial cellular mechanism eventually leading to compulsive drug-seeking behavior. To evaluate the impact of GABA_B receptors on addiction-related persistent neuroplasticity, we tested the ability of orthosteric agonist baclofen and two positive allosteric modulators (PAMs) of GABA_B receptors to suppress neuroadaptations in the ventral tegmental area (VTA) and reward-related behaviors induced by ethanol and cocaine. A novel compound (S)-1-(5-fluoro-2,3-dihydro-1H-inden-2-yl)-4-methyl-6,7,8,9-tetrahydro-[1,2,4]triazolo[4,3-a]quinazolin-5(4H)-one (ORM-27669) was found to be a GABA_B PAM of low efficacy as agonist, whereas the reference compound (R,S)-5,7-di-tert-butyl-3-hydroxy-3-trifluoromethyl-3H-benzofuran-2-one (rac-BHFF) had a different allosteric profile being a more potent PAM in the calcium-based assay and an agonist, coupled with potent PAM activity, in the [³⁵ S] GTPγS binding assay in rat and human recombinant receptors. Using autoradiography, the high-efficacy rac-BHFF and the low-efficacy ORM-27669 potentiated the effects of baclofen on [³⁵ S] GTPγS binding with identical brain regional distribution. Treatment of mice with baclofen, rac-BHFF, or ORM-27669 failed to induce glutamate receptor neuroplasticity in the VTA DA neurons. Pretreatment with rac-BHFF at non-sedative doses effectively reversed both ethanol- and cocaine-induced plasticity and attenuated cocaine i.v. self-administration and ethanol drinking. Pretreatment with ORM-27669 only reversed ethanol-induced neuroplasticity and attenuated ethanol drinking but had no effects on cocaine-induced neuroplasticity or self-administration. These findings encourage further investigation of GABA_B receptor PAMs with different efficacies in addiction models to develop novel treatment strategies for drug addiction.

Do Elevated Temperature and CO2 Generally Have Counteracting Effects on Phenolic Phytochemistry of Boreal Trees?

Global climate change includes concomitant changes in many components of the abiotic flux necessary for plant life. In this paper, we investigate the combined effects of elevated CO2 (720 ppm) and temperature (+2 K) on the phytochemistry of three deciduous tree species. The analysis revealed that elevated CO(2) generally stimulated increased carbon partitioning to various classes of phenolic compounds, whereas an increase in temperature had the opposite effect. The combined effects of both elevated CO2 and temperature were additive, i.e., canceling one another's individual effects. Obviously, the effects of global climate change on leaf chemistry must simultaneously consider both temperature and CO2. If these results are generally applicable, then the counteracting effect of the temperature is likely to play a major role in alpine, boreal, and arctic zones in determining the balance between populations of plants and herbivores.

Point: myeloperoxidase -463G --> a polymorphism and lung cancer risk

Myeloperoxidase (MPO) is released from neutrophils in lung tissue in response to exposure to various pulmonary insults, including tobacco smoking. This enzyme is involved in the activation of an intermediate metabolite of benzo(a)pyrene to the highly reactive benzo(a)pyrene diol epoxide. A (-463)G --> A polymorphism in the promoter region of the MPO gene has been identified. The A allele is associated with a decreased transcriptional activity attributable to the disruption of a SP1-binding site. We therefore examined whether carriers of the A allele may be at reduced risk of lung cancer in a case-control study of 150 cases and 172 control individuals, all Caucasian smokers. Relative to subjects with the MPO G/G genotype, a significant decreased risk of lung cancer was found for carriers of the G/A genotype [odds ratio (OR) = 0.5, 95% confidence interval (CI): 0.29-0.88]. A reduction in risk, although not statistically significant, was also observed for subjects with the A/A genotype (OR = 0.84, 95% CI: 0.31-2.32). The lung cancer risk for carriers of one or two copies of the A allele was 0.55 (95% CI: 0.33-0.93). Because of the low prevalence of the A/A genotype, we also performed a meta-analysis of 2686 lung cancer cases and 3325 controls. The summary OR suggested a slight protective effect of the A/A genotype (OR = 0.86, 95% CI: 0.67-1.1), but this finding was strongly influenced by the results of a single large study. The meta-analysis restricted to studies comprising a homogeneous set yielded an OR of 0.68 (95% CI: 0.5-0.93). However, because of the heterogeneity in individual study results, additional large case-control studies are warranted to provide a more definitive conclusion.

PPP2R1B gene in chronic lymphocytic leukemias and mantle cell lymphomas

Deletion of chromosome bands 11q22-q23 is one of the most common structural chromosome alterations in chronic lymphocytic leukemia (CLL) and mantle cell lymphoma (MCL). The PPP2R1B gene is located very close to the minimal common deletion region of 11q22-q23 in CLL and MCL. Recently, the PPP2R1B gene was found to be mutated in human lung and colon cancers. To evaluate the role of the PPP2R1B gene in the pathogenesis of CLL and MCL, we performed RT-PCR analysis and cDNA sequencing on 10 CLL RNA samples and SSCP analysis on 26 CLL and 37 MCL genomic DNA samples. A deletion of exon 3 was found in one CLL sample. No mutation was detected in the SSCP analysis. To exclude the possibility of large genomic deletions we performed Southern blotting analysis. One MCL sample showed abnormal bands. Our results do not suggest that the PPP2R1B gene has a major pathogenic role in CLL and MCL.

A double-blind, randomized study to compare the efficacy and safety of terbinafine (Lamisil) with fluconazole (Diflucan) in the treatment of onychomycosis

In a randomized, double-blind, double-placebo, multicentre study, terbinafine 250 mg daily for 12 weeks was compared with fluconazole 150 mg once weekly for 12 or 24 weeks in the treatment of onychomycosis. A total of 137 patients with culture-confirmed onychomycosis was divided into three groups: group A received terbinafine for 12 weeks, group B received fluconazole for 12 weeks, while group C received fluconazole for 24 weeks. At completion of the study (week 60), the mycological cure rate was higher in the terbinafine group than in the fluconazole groups: 89% vs. 51% and 49%, respectively (P < 0.001). The length of unaffected nail increased until week 24 in group B and until week 36 in group C, but was still increasing in group A at the final visit (week 60). Complete clinical cure of the target nail at week 60 was 67% in the terbinafine group, compared with 21% and 32% in the fluconazole groups, respectively. The incidence of adverse events was low for both study agents. We conclude that terbinafine 250 mg daily for 12 weeks is significantly more effective in the treatment of onychomycosis than fluconazole 150 mg once weekly for either 12 or 24 weeks.

Neuronal histamine deficit in Alzheimer's disease

Histamine is known to be a neurotransmitter in the brain, but it has not been clearly implicated in major diseases. All histaminergic neurons reside in the posterior hypothalamus and innervate most brain areas, which is compatible with the concept that histamine is involved in general central regulatory mechanisms. A sensitive high-performance liquid chromatographic fluorimetric method was used to measure histamine contents in post mortem Alzheimer brains and age-matched controls. The cellular storage sites and distribution of histaminergic nerve fibers were examined with a specific immunohistochemical method. The histamine content was significantly reduced in the hypothalamus (42% of control value), hippocampus (43%) and temporal cortex (53%) of Alzheimer brains. Differences in other cortical areas, putamen and substantia nigra were not significant. Histamine-containing nerve fibers were found in the hippocampus, parahippocampal gyrus and subiculum of both Alzheimer brains and controls. No histamine-containing mast cells were seen in these temporal structures. Histamine in the human temporal lobe is stored in nerve fibers originating from the posterior hypothalamus, and not in mast cells. Decrease in brain histamine may contribute to the cognitive decline in Alzheimer's disease directly or through the cholinergic system. Development of drugs that penetrate the blood brain barrier and increase histaminergic activity might be beneficial in Alzheimer's disease.

Cloning of the human type XVII collagen gene (COL17A1), and detection of novel mutations in generalized atrophic benign epidermolysis bullosa

Generalized atrophic benign epidermolysis bullosa (GABEB) is a nonlethal variant of junctional epidermolysis bullosa (JEB). Previous findings have suggested that type XVII collagen is the candidate gene for mutations in this disease. We now have cloned the entire human type XVII collagen gene (COL17A1) and have elucidated its intron-exon organization. The gene comprises 56 distinct exons, which span approximately 52 kb of the genome, on the long arm of chromosome 10. It encodes a polypeptide, the alpha1(XVII) chain, consisting of an intracellular globular domain, a transmembrane segment, and an extracellular domain that contains 15 separate collagenous subdomains, the largest consisting of 242 amino acids. We also have developed a strategy to identify mutations in COL17A1 by use of PCR amplification of genomic DNA, using primers placed on the flanking introns. The PCR products are scanned for sequence variants by heteroduplex analysis using conformation-sensitive gel electrophoresis and then are subjected to direct automated sequencing. We have identified several intragenic polymorphisms in COL17A1, as well as mutations, in both alleles, in two Finnish families with GABEB. The probands in both families showed negative immunofluorescence staining with an anti-type XVII collagen antibody. In one family, the proband was homozygous for a 5-bp deletion, 2944del5, which resulted in frameshift and a premature termination codon of translation. The proband in the other family was a compound heterozygote, with one allele containing the 2944del5 mutation and the other containing a nonsense mutation, Q1023X. These results expand the mutation database in different variants of JEB, and they attest to the functional importance of type XVII collagen as a transmembrane component of the hemidesmosomes at the dermal/epidermal junction.

Clinical, light and electron microscopic features of recessive congenital ichthyosis type I

Based on electron microscopic features, recessive congenital ichthyoses have recently been divided into four subgroups designated ichthyosis congenita (IC) types I, II, III and IV. Type II is characterized by cholesterol clefts in the horny cells, type III by perinuclear elongated membranes in the granular and horny cells, and type IV by masses of lipid membranes in granular and horny cells. Clear electron microscopic criteria for type I are lacking, although the presence of lipid droplets in the horny cells has been suggested as a criterion. In the present study we included ichthyosis patients with (i) recessive inheritance, (ii) erythrodermic fine scaling, (iii) lack of fine structural markers of IC types II-IV. Patients with ichthyotic syndromes were excluded. The case material consisted of 21 patients from 14 families. Eight were collodion babies at birth, but three were normal. Nine had ectropion, the flexures were affected in 12, and the palms and soles were thickened in all but one patient. On electron microscopy lipid vacuoles in the horny cells were common, but were absent in four patients. Changes in other lipid-related structures, including keratinosomes, were common. We conclude that currently type I can be diagnosed only by excluding the other types of ichthyosis. Clinically, IC type I corresponds to classical non-bullous congenital ichthyosiform erythroderma, but there is marked heterogeneity among affected individuals.

Recessive ichthyosis congenita type IV

Two patients suffering from ichthyosis with unusual ultrastructural features were examined. One was a 14-year-old boy with ichthyotic skin since birth. The ichthyosis was initially erythrodermic and later presented as follicular hyperkeratosis. The other patient was an ichthyotic child who died 2 days after birth of respiratory distress syndrome. Although apparently not consanguineous, both families came from the same relatively isolated rural area and autosomal recessive inheritance seems likely. Light microscopy did not yield diagnostic features, but the ultrastructural findings in the granular and horny cells showed diagnostic lamellar membrane packages. Identical ultrastructural features have previously been published in one prematurely born baby who died soon after birth and once in a prenatal diagnosis in the same family; the disease was termed "ichthyosis congenita type IV".

Birthmarks in 4346 Finnish newborns

We examined all babies born live (4346) at two Finnish hospitals in the course of one year to determine the frequency of birthmarks, specially pigmented lesions, among Finnish newborns. All birthmarks excluding common salmon patches on the forehead and neck were recorded and photographed at birth. The babies were re-examined at the age of three months. Various birthmarks were recorded for 241 of 4346 babies, i.e. for 5.5% of all newborns. Ninety-one (2.1%) infants had congenital pigmented skin lesions, 167 (3.8%) had various vascular lesions and 21 (0.5%) had other birthmarks. The frequency of congenital melanocytic naevi was 1.5%. Most of the naevi were less than 20 mm in diameter. Only one child had a giant naevus. The frequency of congenital naevi in our study was the same or somewhat higher than previously described (1-8) but fewer other pigmented skin lesions were found than in previous studies perhaps due to racial differences.

Recessive ichthyosis congenita type II

In the heterogeneous group of recessive congenital ichthyoses the disorder of desquamation seems to be a basic problem. Desquamation is strongly dependent on the normal lipid metabolism of the keratinocytes. We describe a group of patients who have a typical clinical picture of large scale ichthyosis and cholesterol clefts in the thickened corneal layer, evidencing a disturbance of the lipid metabolism of the skin. The corneocytes also show a thin or absent cornified envelope, which could indicate a disturbance of protein synthesis. These patients have a severe ichthyosis, but good general health and no associated symptoms. This disorder has recently been named 'ichthyosis congenita type II' by the Heidelberg group on the basis of electron microscopic findings. According to the present examination this group corresponds clinically to the currently used diagnosis 'lamellar ichthyosis'.

Neuropeptides in cutaneous neurofibromas of von Recklinghausen's disease

The occurrence of neuropeptides was studied in neurofibromas of von Recklinghausen's disease by indirect immunofluorescence. All non-plexiform cutaneous neurofibromas contained abundant vasoactive intestinal polypeptide, peptide histidine-isoleucine and calcitonin gene-related peptide immunoreactive nerves. The nerves were small and unmyelinated. Neuropeptides might be responsible for itch that occurs especially in small cutaneous neurofibromas. Neuropeptides are also suggested to act as modulators and/or trophic factors for neurofibroma growth.

Parakeratotic horns in a patient with myeloma

We describe a patient who in association with myeloma developed generalized keratotic horns. Light microscopy revealed parakeratotic plugs resembling those seen in Kyrle's disease. Electron microscopy showed distortion of keratinosomes and laminated bodies indicating a profound disturbance in keratinization. A strong C3 and weaker IgG and IgA immunofluorescence were seen in the areas of epidermal plugs and horns but no circulating epidermal antibodies were detected. All symptoms disappeared when therapy for myeloma was started favoring that they were of paraneoplastic origin.

Evaluation of delayed type immune reactivity in patients with acne vulgaris

The delayed-type immune reactivities of 39 patients suffering from moderate to severe papulopustular or nodulo-cystic forms of Acne vulgaris were compared with healthy acne-free controls. In vivo reactivity was assessed by skin testing with four common recall antigens. In vitro the afferent arm of the immune system was assayed by antigen and mitogen simulated lymphocyte transformation and the efferent arm by granulocyte random migration and by granulocyte responsiveness to a standard migration inhibitory lymphokine preparation. Spontaneous lymphocyte transformations were also evaluated. In acne patients the skin test reactivities were in general only slightly decreased. Their lymphocytes showed relatively normal responses to mitogen stimulation, but antigen responsiveness was significantly diminished. Furthermore the patients' lymphocytes showed increased spontaneous transformation. All these changes correlated, to some extent, with the severity of the disease. The granulocytes of acne patients showed increased random migration, of borderline significance, but the granulocyte responses to the lymphokine preparation were completely normal. The results suggest that immunologic abnormalities are mild and probably secondary to the inflammatory process.

Antihypertensive effect of prazosin in combination with methyldopa, clonidine, or propranolol

Seventeen hypertensive out-patients, more or less unresponsive to previous treatment with antihypertensive drugs, were treated in a cross-over fashion with placebo, prazosin (Pz), methyldopa (MD), Pz + MD, Pz + clonidine (C) and Pz + propranolol. The antihypertensive responses to Pz 2 mg t.i.d. and MD 250 mg t.i.d. were poor, and only modest when the drugs were combined. The combination of Pz with low doses of C was about as effective as Pz + MD, and some patients failed to respond to it. Nor was the combination of Pz + propranolol effective in those cases but the addition of a diuretic produced good responses in all patients. Side effects were few. It is concluded that a combination of central and peripheral sympathetic blockade does not necessarily produce normotension, and that a diuretic added to this combination greatly improves the response.

Comparison of a new antihistamine HC 20-511 with cyproheptadine (Periactin) in chronic urticaria

The effect and tolerance of a new antihistamine, HC 20-511, in daily doses of 2 and 4 mg was compared with cyproheptadine (Periactin) 8 mg daily in 50 cases of chronic urticaria. HC 20-511 4 mg daily proved to be the most effective, rapid and long-lasting. HC 20-511 had less sedative effect than cyproheptadine, but both possessed the same appetite-stimulating effect. However, this was not noted with the smaller dosage of HC 20-511.

Comparison of 0.25% desoxymethasone ointment with 0.05% fluocinonide ointment in psoriasis

A double-blind comparative trial was carried out in 56 patients with psoriasis to assess the effectiveness of 0.25% desoxymethasone and 0.05% fluocinonide ointments. All patients showed marked improvement in their condition with twice daily application of the ointments during the 2-week period of the trial. Erythema, scaling and induration on the desoxymethasone-treated side showed a significantly better improvement than on the fluocinonide-treated side.

A new antihistamine hc20-511 compared with dimetinden (fenistil retard) in the treatment of chronic urticaria and other pruritic dermatoses

The new antihistamine, HC20-511 (Sandoz), was compared with Dimetinden (Fenistil retard) in a single-blind comparative study in 42 patients with dermatoses, 28 of whom suffered from chronic urticaria. HC20-511 had a better effect, especially in chronic urticaria, where pruritus, erythema and papules quickly disappeared. The effect appeared somewhat faster than and lasted as long as that of Dimetinden, although HC20-511 is not a retard-preparation unlike the Dimetinden preparation used for comparison. HC20-511 also caused less side effects.

Replica reflection of normal skin and of skin with disturbed keratinization

No abstract available