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PubMed1996

Stable functional expression of the adult subtype of human muscle acetylcholine receptor following transfection of the human rhabdomyosarcoma cell line TE671 with cDNA encoding the epsilon subunit.

The human rhabdomyosarcoma cell line TE671 expresses the foetal subtype of muscle acetylcholine receptor (AChR). By transfecting TE671 cells with cDNA encoding the human muscle AChR epsilon subunit under the control of the cytomegalovirus promoter we have established a stable cell clone that, in addition, constitutively expresses the adult AChR subtype. Both subtypes are inserted into the plasma membrane and demonstrate their respective characteristic single channel properties. The level of expression of the adult AChR subtype is two- to three-fold higher than that of the foetal subtype. The new cell clone provides a relatively abundant source of human adult AChR for immunological and pharmacological investigations.

DNA, Complementary↗
PubMed1989

Muscarinic receptor subtype specificity of 5'-(isobutylthio)-adenosine (SIBA) and its analogs.

1. 5'(Isobutylthio)-adenosine (SIBA) and its analogs, at 100 microM, inhibited [3H]N-methyl-scopolamine binding to homogenates of whole brain and cortex (mainly M1 subtype receptors) by 11-30% and to cerebellum (mainly M2 subtype receptors) by 20-39%. 2. At 0.01-1.0 microM, stimulation of [3H]QNB and NMS-inaccessible [3H]QNB binding was observed, with the most induced by 1 microM 3-deaza-SIBA. 3. In contrast, [3H]pirenzepine ([3H]PZ) binding to whole brain and cortex was inhibited in a dose-dependent manner with Ki values in the microM range. 4. As antagonists of acetylcholine-induced contraction of guinea pig ileum (mainly M2 subtype receptors), the analogs were slightly more potent than pirenzepine, but several orders of magnitude less than atropine; the order of potency was opposite that determined for the binding of [3H]PZ to cortex. 5. Thus, SIBA and its analogs may have differential effects on muscarinic receptor subtypes and show some specificity for the M1 receptor subtype.

Acetylcholine↗
PubMed1993

Subtype classification of presynaptic alpha 2-adrenoceptors.

1. Presynaptic alpha 2-adrenoceptors in a few tissues have recently been pharmacologically classified in functional studies. 2. Autoreceptors are of alpha 2A-subtype in rabbit occipito-parietal cortex, rat cerebral cortex, vas deferens, submandibular gland, kidney, guinea-pig ileum submucosal arterioles and urethra. 3. Heteroreceptors are of alpha 2A-subtype in rat cerebral cortex, vas deferens, guinea-pig ileum submucosal plexus and Auerbach's plexus. 4. In rat atria autoreceptors have been shown to be of alpha 2B-subtype. 5. Classification is done mainly with alpha 2A-adrenoceptor-selective oxymetazoline, WB 4101 and BRL 44408, and the alpha 2B-adrenoceptor-selective prazosin, AR-C 239, chlorpromazine and BRL 41992. 6. With four alpha 2-adrenoceptor subtypes to consider, a larger number of subtype-selective compounds may have to be characterized in the classification in the many tissues, where presynaptic alpha 2-adrenoceptors are found.

Animals↗
PubMed1994

Pre- and postjunctional muscarinic receptor subtypes in the vas deferens of rat.

1. A pharmacological study of the pre- and postjunctional muscarinic receptors of the isolated rat vas deferens was carried out using more selective agonists and antagonists. 2. The prejunctional receptor was characterized on electrically stimulated preparations, while the postjunctional receptor was studied on vasa deferentia without stimulation. 3. The results indicate that atropine exhibited a similar affinity for the two populations of muscarinic receptor subtypes of this tissue. 4. 4-DAMP was able to differentiate with high affinity a subtype located at postjunctional level which had pharmacological similarities with the M3-ACh subtype and with low affinity a subtype located at prejunctional level. 5. The selective M1-ACh agonist McN-A-343 was not able to activate the postjunctional receptor, but showed a similar affinity to ACh for the prejunctional one. 6. At present, the prejunctional receptor can be considered as an atypical M1-ACh subtype based on the results obtained with the selective drugs available.

Animals↗
PubMed1995

Localization of serotonin subtype 6 receptor messenger RNA in the rat brain by in situ hybridization histochemistry.

The serotonin receptor subtype 6, which raises intracellular cyclic AMP via stimulatory G-proteins, has recently been cloned and characterized. To determine the distribution of serotonin subtype 6 messenger RNA, in situ hybridization was performed in coronal sections of rat brain. 35S-labeled riboprobe, complementary to the 5' non-coding region of the serotonin subtype 6 messenger RNA, and a 33P-labeled riboprobe complementary to its 3' non-coding region, were used for hybridization. Serotonin subtype 6 receptor message was found in serotonin projection fields, rather than regions of serotonin-containing cell bodies, suggesting that the receptor is mainly postsynaptic. Hybridization signal was highest in olfactory tubercle, as well as prominent in the striatum, nucleus accumbens, dentate gyrus, and CA1, CA2 and CA3 of the hippocampus. Less intense hybridization was observed in cerebellum, some diencephalic nuclei, the amygdala, and layers 2, 3, 4 and 6 of the cortex. This pattern of hybridization was observed with both probes, but not when sense transcripts were used. Because the serotonin subtype 6 receptor has a high affinity for the atypical antipsychotic clozapine, and because striatum and nucleus accumbens are proposed sites of antipsychotic drug effects, the possibility is raised that this receptor may play an important role in mediating the effects of the atypical antipsychotic agents.

Animals↗
PubMed1995

Distribution of protein kinase C (alpha, beta, gamma subtypes) in normal nerve fibers and in regenerating growth cones of the rat peripheral nervous system.

The distribution of protein kinase C (alpha, beta, gamma subtypes) was studied using immunocytochemical techniques in normal nerve fibers and in regenerating sprouts (growth cones) from the nodes of Ranvier following crush injuries to the rat peripheral nervous system. In normal nerves, for each protein kinase C subtype, immunoreactivity was present in both myelinated and unmyelinated axons. In myelinated axons, immunoreactivity for all three subtypes was patchy in the axoplasm and diffuse in the subaxolemmal peripheral zones. No immunoreactivity was found in the microtubule and neurofilament (cytoskeletal) domain. In contrast, in unmyelinated axons, immunoreactivity was distributed diffusely in the axoplasm. Schwann cells of myelinated fibers exhibited protein kinase C immunoreactivity, but those of unmyelinated fibers did not. In regenerating nerves, early sprouts and growth cones extending through the crushed site along Schwann cell basal laminae exhibited intense immunoreactivity for all three subtypes. Immunoreactivity was distributed diffusely throughout the axoplasm of the regenerating sprouts (growth cones), in which microtubules and neurofilaments were very rare. Thus, the subcellular localization of the protein kinase C immunoreactivity in growth cones of early regenerating nerves differed from that of normal parent axons. These findings suggest that protein kinase C (alpha, beta and gamma subtypes), whose subcellular distribution becomes more extensive in regenerating axons, may have important functional roles in axonal sprouting and in the regulation of growth cone activity in the peripheral nervous system.

Animals↗
PubMed1992

Outcome of conservative therapy for invasive breast cancer by histologic subtype.

Between 1977 and 1986, 879 patients with Stage I and II breast cancer underwent excisional biopsy, axillary dissection, and radiation. Median follow-up was 61 months (range 2-159 months). The patients were divided into seven groups based on histologic subtype: (a) 368 patients with both infiltrating and intraductal ductal carcinoma, (b) 389 infiltrating ductal carcinoma, (c) 41 infiltrating lobular carcinoma, (d) 23 combined infiltrating ductal and lobular carcinoma, (e) 28 medullary carcinoma, (f) 12 colloid carcinomas, and (g) 18 tubular carcinomas. Significant differences in clinical T status, pathologic nodal involvement, administration of chemotherapy, estrogen receptor positivity, progesterone receptor positivity, and age were observed between some histologic subgroups. Tubular and colloid carcinomas were more likely to present with T1 lesions, hormone receptor positivity, and node negative status than the other histologic subtypes. Most medullary carcinomas were hormone receptor negative and were younger than 50 years old. Infiltrating lobular carcinoma patients were more frequently lymph node negative, older, node negative, and estrogen receptor positive compared to the other groups (except for tubular and colloid patients). Differences in the administration of chemotherapy primarily reflected differences in lymph node involvement. Location of the tumor in the breast and menopausal status did not correlate with histologic subtype. There were no significant differences in 5-year actuarial overall survival, cause-specific survival, or relapse-free survival between the histologic categories. In addition, patterns of first failure were not significantly different among the histologic groups in terms of local-only first failure, any local component of first failure, regional-only first failure, or any regional component of first failure. There was, however, a difference among the seven groups in distant metastasis-only at first failure with invasive ductal carcinomas having the highest rate. Despite this difference, histologic subtype had no impact on survival. The site of in-breast failure relative to the location of the original tumor was not significantly different between groups. The histologic subtype of invasive breast cancer is not an independent risk factor in predicting survival or pattern of failure. Conservative surgery and radiation therapy is effective treatment of ductal, lobular, medullary, colloid, and tubular invasive breast cancer.

Adenocarcinoma↗
PubMed1992

Empirical subtypes of DSM-III-R alcohol dependence: United States, 1988.

The purpose of the present study was to quantify the degree of heterogeneity of the DSM-III-R alcohol dependence category by comparing the number of potential subtypes of dependence to those empirically observed in a general population survey. Forty-one percent (n = 189) of the 466 potential subtypes of DSM-III-R alcohol dependence were observed, indicating that the category is indeed heterogeneous, but not as heterogeneous as theoretically predicted. Variations in the number, percent and configuration of empirical subtypes of dependence are discussed in terms of coincident morbidity, premature death from alcoholism or death from other competing causes, reporting biases and differences in drinking patterns. The predominance of the 'tolerance' 'withdrawal' and 'impaired control over drinking' criteria among the empirically observed subtypes of dependence are examined within the context of the physiological dependence subtype proposed for the DSM-IV category of alcohol dependence and difficulties encountered in operationalizing these diagnostic criteria. The relevance of study findings to the validation of diagnostic categories in psychiatry is also highlighted.

Adolescent↗
PubMed1996

Cloning of the cDNA encoding a novel subtype of histone H1.

The H1 class of histones is implicated in organizing a higher order of chromatin structure and in involvement with transcriptional repression. They compromise multiple subtypes that presumably have a specific function. We report here the isolation and characterization of a human cDNA encoding a novel subtype of histone H1. It is the most distantly related subtype of mammalian H1 reported to date. However, it still shares the characteristic features of H1: the tripartite structure, conservation in the globular domain, the profile of hydropathy and the basic isoelectric point. The expression of this H1 subtype was ubiquitously observed in all tissues examined. Our findings suggest that novel subtypes of H1 may remain unidentified in mammals.

Amino Acid Sequence↗
PubMed1989

Glutamate receptor subtypes may be classified into two major categories: a study on Xenopus oocytes injected with rat brain mRNA.

Three major subtypes of glutamate receptors that are coupled to cation channels are known. Recently an additional subtype that is coupled to G proteins and stimulates inositol phospholipid metabolism (the metabotropic glutamate receptor) has been proposed. The pharmacological characteristics of this receptor have now been examined. Although it shares some agonists with N-methyl-D-aspartate- and quisqualate-subtype receptors, it shares virtually no antagonists with any of the three cation channel-coupled receptor subtypes. Thus the metabotropic glutamate receptor belongs to a receptor category that is completely different from that of the other three receptor subtypes, not only functionally, but also pharmacologically.

Animals↗
PubMed1995

Use of recombinant alpha 1-adrenoceptors to characterize subtype selectivity of drugs for the treatment of prostatic hypertrophy.

Several alpha 1-adrenoceptor antagonists have recently been developed for the treatment of benign prostatic hypertrophy because of their less frequent systemic side-effects compared to conventional alpha 1-adrenoceptor blockers. One potential explanation for their good tolerability would be the selectivity for a certain subtype of alpha 1-adrenoceptor. Utilizing COS-7 cells expressing the rat alpha 1A, the hamster alpha 1B and the human alpha 1C-adrenoceptors, we investigated affinities of alfuzosin, doxazosin, terazosin, indoramin and (+)- and (-)-5-[2-[[2-(o-ethoxyphenoxy)ethyl] amino]propyl]-2-methoxybenzesulfonamide HCl (YM 617) compared to prazosin. Radioligand binding studies showed that the affinities of alpha 1-adrenoceptor subtypes for alfuzosin (Ki value; alpha 1A: 2.4 nM, alpha 1B:1.4 nM, alpha 1C:4.2 nM), doxazosin (Ki value; alpha 1A:2.7 nM, alpha 1B:3.2 nM, alpha 1C:7.5 nM), terazosin (Ki value; alpha 1A:2.5 nM, alpha 1B:2.7 nM, alpha 1C:7.1 nM), indoramin (Ki value; alpha 1A:69 nM, alpha 1B:21 nM, alpha 1C:13 nM) and prazosin (Ki value; alpha 1A:0.16 nM, alpha 1B:0.19 nM, alpha 1C:0.2 nM) were equipotent to the three receptor subtypes. Unlike these antagonists, both (+)- and (-)-YM617 had relatively lower affinity for alpha 1B receptors compared to the other subtypes (Ki value; for (+)-YM617, alpha 1A:22 nM, alpha 1B:96 nM, alpha 1C:4.3 nM; for (-)-YM617, alpha 1A:0.11 nM, alpha 1B:0.7 nM, alpha 1C:0.035 nM). The data suggest that alpha 1-adrenoceptor antagonists currently used for the treatment of the benign prostatic hyperplasia do not show substantial subtype selectivity.

Adrenergic alpha-1 Receptor Antagonists↗
PubMed1996

HIV-1 D subtype viruses in Finland.

BACKGROUND: Human immunodeficiency virus (HIV)-1 strains are divided into seven genetic subtypes based on their gag sequences (A, B, C, D, F, G and H). Strains that have appeared in Finland show unusual heterogeneity compared to most industrialized countries, up to 25% of the strains belong to non-B subtypes (Liitsola et al., 1996). Three D subtype viruses have so far been identified in Finland. All patients were men, one Kenyan immigrant and two Finnish men, who had been infected in Africa. Here we describe some of the characteristics of the genomic diversity of these strains. METHOD: The genotype was determined by direct solid-phase sequencing of the p7 gag region. Phylogenetic analysis was done using standard methods. RESULTS: The analysis showed that the D subtype sequences clustered clearly distinctly from the other non-B strains, but did not suggest any transmission links between the three cases. From one case both cerebrospinal fluid (CSF) and blood leukocyte virus isolates were studied. The analysis revealed significant differences between the blood and CSF viruses. A four amino acid duplication and other differences were observed between the strains. CONCLUSION: The results confirm that D subtype viruses do indeed occur in Finland and they represent quite heterogenic strains within the D cluster.

Journal Article↗
PubMed1995

Evaluation of stereoisomers of 4-fluoroalkyl analogues of 3-quinuclidinyl benzilate in in vivo competition studies for the M1, M2, and M3 muscarinic receptor subtypes in brain.

To develop a subtype selective muscarinic acetylcholine receptor (mAChR) antagonist for PET, fluorine-19 labeled alkyl analogues of quinuclidinyl benzilate (QNB) were synthesized by stereoselective reactions. To investigate these analogues for tissue subtype specificity, in vivo competitive binding studies were performed in rat brain using (R)-3-quinuclidinyl (R)-4-[125I]iodobenzilate (IQNB). Five, fifty, or five-hundred nmol of the non-radioactive ligands were coinjected intravenously with 8 pmol of the radioligand, Cold (R,R)-IQNB blocked (R,R)-[125I]IQNB in a dose-dependent manner, without showing regional specificity. For the (R,S)-fluoromethyl, -fluoroethyl and -fluoropropyl derivatives, a higher percent blockade was seen at 5 and 50 mmol levels in M2 predominant tissues (medulla, pons, and cerebellum) than in M1 predominant tissues (cortex, striatum and hippocampus). The blockade pattern of the radioligand also correlated qualitatively with the percentage of M2 receptors in the region. The S-quinuclidinyl analogues showed M2 selectivity but less efficient blockade of the radioligand, indicating lower affinities. Radioligand bound to the medulla was inversely correlated to the M2 relative binding affinity of the fluoroalkyl analogues. These results indicate that the nonradioactive ligand blocks the radioligand based on the affinity of the nonradioactive ligand for a particular receptor subtype compared to the affinity of the radioligand for the same receptor subtype. Of the seven compounds evaluated, (R,S)-fluoromethyl-QNB appears to show the most selectivity for the M2 subtypes in competition studies in vivo.

Animals↗
PubMed2006

bft gene subtyping in enterotoxigenic Bacteroides fragilis isolated from children with acute diarrhea.

Enterotoxigenic Bacteroides fragilis (ETBF) strains are associated with diarrhea disease in farm animals and young children. In this study, the bft gene subtyping from ETBF strains recovered from one immunodeficient and two immunocompetent children with diarrhea were determined. Thirteen ETBF strains were isolated and by using a multiplex-PCR their bft subtypes were determined. All 13 ETBF strains harbored the bft-1 subtype and by AP-PCR they were clustered in the same group I. This study shows that ETBF strains can be present in acute diarrhea and that bft-1 subtype is often present in these organisms. However, further studies are needed to evaluate the role of this bft-1 subtype in the pathogenesis of diarrhea.

Acquired Immunodeficiency Syndrome↗
PubMed2005

Association between the 5HT1B receptor gene (HTR1B) and the inattentive subtype of ADHD.

BACKGROUND: Preclinical and genetic studies have implicated the 5HT1B receptor gene (HTR1B) in attention-deficit/hyperactivity disorder (ADHD). Association with a single nucleotide polymorphism (SNP; G861C) has been observed, but more extensive linkage disequilibrium analyses have not been reported. METHODS: To examine haplotype structure, we genotyped 21 SNPs in and around the gene in 12 multigenerational CEPH pedigrees. We identified a haplotype block encompassing HTR1B and performed haplotype and single-marker association analyses for the eight SNPs within or flanking this block in 229 families of ADHD probands. In light of previous studies suggesting distinct genetic influences on ADHD subtypes, we also examined association with the inattentive and combined subtypes. RESULTS: We observed nonsignificant overtransmission of the G861 allele to ADHD offspring (one-tailed p = .07). Single-marker and haplotype tests of a haplotype block encompassing HTR1B revealed no other associations with ADHD. However, this haplotype block was associated with the inattentive subtype (global p < .01). Additionally, three SNPs in this block were nominally (p < .05) associated with the inattentive subtype, although these did not remain significant after correction for multiple testing. As reported in previous studies, we found paternal overtransmission of the G861 allele to offspring with ADHD; this appeared to be largely attributable to inattentive cases. CONCLUSIONS: These analyses suggest that variation in the HTR1B gene may primarily affect the inattentive subtype of ADHD.

Adolescent↗
PubMed2006

Dimensional analysis of ADHD subtypes in rats.

BACKGROUND: Attention-deficit/hyperactivity disorder is a heterogeneous disorder that is classified into three subtypes in which the main symptoms, inattention, hyperactivity, and impulsivity, are expressed with various degrees of severity. The nature of the biological dysfunction sustaining each subtype (common or distinct) is unknown, and animal models encompassing different subtypes are needed. METHODS: A cluster analysis separated subgroups of rats on the basis of similarities in both impulsivity and attentional scores in the five-choice serial reaction time task. These subgroups were characterized behaviorally and were compared for several aspects of spontaneous hyperactivity in different environmental contexts. The dose effects of two agents used clinically (methylphenidate and atomoxetine) were tested on attention and impulsivity. RESULTS: Four distinct subgroups were demonstrated: efficient, middle, inattentive, and inattentive-impulsive. Hyperactivity expressed in a cage, characterized the last subgroup. Subgroups were differentially sensitive to environmental and pharmacologic challenges. Methylphenidate increased impulsivity mainly in the combined subgroup, whereas atomoxetine decreased impulsivity, neither with any effect on the efficient subgroup and on accuracy. CONCLUSIONS: This new approach is the first to demonstrate behavioral subtypes in rats that parallel those observed in human beings and is a promising tool to clarify the biological bases of these behavioral subtypes and to explain therapeutic effects.

Adrenergic Uptake Inhibitors↗
PubMed2007

Attention and executive functions profile in drug naive ADHD subtypes.

Attention deficit hyperactivity disorder (ADHD) has been associated with executive functioning and sustained and divided attention deficits. In order to clarify the questions on neurocognitive impairment in ADHD, we investigated the presence of specific executive functions (EFs) and attention deficit patterns in ADHD clinical subtypes. 50 patients with ADHD and 44 controls were evaluated. All subjects were boys and performed a clinical-psychopathological and neuropsychological battery. Five main domains of EFs and attention were studied. Executive functions-related neurocognitive abilities were used as control tasks. ADHD patients, inattentive and combined subtypes differ from controls on response inhibition, divided attention, phonological, and visual object working memory and on variability of reaction times measured with CPT. Comparison of ADHD subtypes, in five main domains of EFs, did not show evidence of different executive functioning profiles. Response inhibition can predict performance on working memory tests but it cannot predict performance on divided attention/set shifting and on sustained attention. ADHD boys exhibit a selective impairment on executive functions and attention tasks. These data suggest the involvement of partially independent neural circuits which control inhibition and divided attention in ADHD. Since right prefrontal cortex seems to be crucial in controlling response inhibition, while left dorsolateral prefrontal cortex seems important in modulating divided attention, these areas are deputated to be involved in the pathogenesis of neuropsychological deficits in ADHD subtypes. In addition, this study candidates the impairment in phonological and visual-object working memory as a possible neuropsychological trait in ADHD males with inattentive or combined subtypes.

Attention↗
PubMed2004

The Y1 receptor subtype mediates the cardiovascular changes evoked by NPY administered into the posterior hypothalamic nucleus of conscious rat.

An earlier study showed that the neuropeptide Y (NPY) receptor antagonist PYX-2 blocks the enhancement of a carbachol (CCh)-evoked pressor response produced by prior NPY administration into the posterior hypothalamic nucleus (PHN). The Y receptor subtype that mediates this response, and an increase in mean arterial pressure (MAP) and heart rate, remained unknown due to the lack of selectivity of PYX-2 for the Y receptor subtypes. Thus, the present study was undertaken to elucidate the Y receptor subtype responsible for mediating the NPY-evoked cardiovascular responses from the PHN by determining the rank order of potency of several NPY-related peptides for increasing MAP, and by correlating the pressor response evoked by these peptides to reported K(i)'s and IC(50)'s for the Y(1), Y(2), Y(4) and Y(5) receptor subtypes. The pharmacological profile (PYY>or=NPY>or=[Leu(31),Pro(34)]NPY>or=NPY(13-36)>or=hPP) and correlations suggest that the Y(1) and/or Y(5) receptor subtypes mediate these cardiovascular changes. Administration of the relatively non-selective Y receptor antagonist PYX-2 or the selective Y(1) receptor antagonist BIBP 3226 into the PHN prior to NPY completely blocked the cardiovascular responses. BIBP 3226 also blocked the cardiovascular changes evoked by [Leu(31),Pro(34)]NPY, NPY(13-36) and human pancreatic polypeptide (hPP). In contrast, neither BIBP 3226 nor PYX-2 inhibited the cardiovascular changes induced by peptide YY (PYY) or CCh microinjection into the PHN. These results show that NPY and PYY act on different receptors to mediate their respective cardiovascular changes from the PHN with NPY stimulating the Y(1) receptor.

Animals↗